lgpio.h

/*
This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <http://unlicense.org/>
*/

#ifndef LGPIO_H
#define LGPIO_H

#include <stdint.h>
#include <inttypes.h>
#include <pthread.h>
#include <linux/gpio.h>

#define LGPIO_VERSION 0x00010700

#define LG_CD "LG_CD"  /* configuration directory */
#define LG_WD "LG_WD"  /* working directory */

/*TEXT

lgpio is a C library for Linux Single Board Computers which
allows control of the General Purpose Input Output pins.

*Features*

o reading and writing GPIO singly and in groups
o software timed PWM and waves
o GPIO callbacks
o pipe notification of GPIO alerts
o I2C wrapper
o SPI wrapper
o serial link wrapper
o a simple interface to start and stop new threads

*Usage*

Include <lgpio.h> in your source files.

Assuming your source is in a single file called prog.c use the following
command to build and run the executable.

. .
gcc -Wall -o prog prog.c -llgpio
./prog
. .

For examples of usage see the C programs within the lg archive file.

*Notes*

All the functions which return an int return < 0 on error.

TEXT*/

/*OVERVIEW

GPIO

lgGpiochipOpen               Opens a gpiochip device
lgGpiochipClose              Closes a gpiochip device

lgGpioGetChipInfo            Gets gpiochip information
lgGpioGetLineInfo            Gets gpiochip line information
lgGpioGetMode                Gets the mode of a GPIO

lgGpioSetUser                Notifies Linux of the GPIO user

lgGpioClaimInput             Claims a GPIO for input
lgGpioClaimOutput            Claims a GPIO for output
lgGpioClaimAlert             Claims a GPIO for alerts
lgGpioFree                   Frees a GPIO

lgGroupClaimInput            Claims a group of GPIO for inputs
lgGroupClaimOutput           Claims a group of GPIO for outputs
lgGroupFree                  Frees a group of GPIO

lgGpioRead                   Reads a GPIO
lgGpioWrite                  Writes a GPIO

lgGroupRead                  Reads a group of GPIO
lgGroupWrite                 Writes a group of GPIO

lgTxPulse                    Starts pulses on a GPIO
lgTxPwm                      Starts PWM pulses on a GPIO
lgTxServo                    Starts Servo pulses on a GPIO
lgTxWave                     Starts a wave on a group of GPIO
lgTxBusy                     See if tx is active on a GPIO or group
lgTxRoom                     See if more room for tx on a GPIO or group

lgGpioSetDebounce            Sets the debounce time for a GPIO
lgGpioSetWatchdog            Sets the watchdog time for a GPIO

lgGpioSetAlertsFunc          Starts a GPIO callback
lgGpioSetSamplesFunc         Starts a GPIO callback for all GPIO

I2C

lgI2cOpen                    Opens an I2C device
lgI2cClose                   Closes an I2C device

lgI2cWriteQuick              SMBus write quick

lgI2cReadByte                SMBus read byte
lgI2cWriteByte               SMBus write byte

lgI2cReadByteData            SMBus read byte data
lgI2cWriteByteData           SMBus write byte data

lgI2cReadWordData            SMBus read word data
lgI2cWriteWordData           SMBus write word data

lgI2cReadBlockData           SMBus read block data
lgI2cWriteBlockData          SMBus write block data

lgI2cReadI2CBlockData        SMBus read I2C block data
lgI2cWriteI2CBlockData       SMBus write I2C block data

lgI2cReadDevice              Reads the raw I2C device
lgI2cWriteDevice             Writes the raw I2C device

lgI2cProcessCall             SMBus process call
lgI2cBlockProcessCall        SMBus block process call

lgI2cSegments                Performs multiple I2C transactions
lgI2cZip                     Performs multiple I2C transactions

NOTIFICATIONS

lgNotifyOpen                 Request a notification
lgNotifyClose                Close a notification
lgNotifyPause                Pause notifications
lgNotifyResume               Start notifications

SERIAL

lgSerialOpen                 Opens a serial device
lgSerialClose                Closes a serial device

lgSerialReadByte             Reads a byte from a serial device
lgSerialWriteByte            Writes a byte to a serial device

lgSerialRead                 Reads bytes from a serial device
lgSerialWrite                Writes bytes to a serial device

lgSerialDataAvailable        Returns number of bytes ready to be read

SPI

lgSpiOpen                    Opens a SPI device
lgSpiClose                   Closes a SPI device

lgSpiRead                    Reads bytes from a SPI device
lgSpiWrite                   Writes bytes to a SPI device

lgSpiXfer                    Transfers bytes with a SPI device

THREADS

lgThreadStart                Start a new thread
lgThreadStop                 Stop a previously started thread

UTILITIES

lguVersion                   Gets the library version
lguSbcName                   Gets the host name of the SBC

lguGetInternal               Get an internal configuration value
lguSetInternal               Set an internal configuration value

lguSleep                     Sleeps for a given time

lguTimestamp                 Gets the current timestamp
lguTime                      Gets the current time

lguErrorText                 Gets a text description of an error code

lguSetWorkDir                Set the working directory
lguGetWorkDir                Get the working directory

OVERVIEW*/

#ifdef __cplusplus
extern "C" {
#endif

#if __BIG_ENDIAN__

#define htonll(x) (x)
#define ntohll(x) (x)

#else

#define htonll(x) (((uint64_t)htonl((x)&0xffffffff)<<32)|htonl((x)>>32))
#define ntohll(x) (((uint64_t)ntohl((x)&0xffffffff)<<32)|ntohl((x)>>32))

#endif

#define LG_CFG_ID_DEBUG_LEVEL 0
#define LG_CFG_ID_MIN_DELAY   1

#define LG_MAX_PATH 1024

#define LG_THREAD_NONE    0
#define LG_THREAD_STARTED 1
#define LG_THREAD_RUNNING 2

#define LG_NOTIFY_CLOSED   0
#define LG_NOTIFY_CLOSING  1
#define LG_NOTIFY_RUNNING  2
#define LG_NOTIFY_PAUSED   3

#define MAX_REPORT 250
#define MAX_SAMPLE 4000

#define MAX_EMITS (PIPE_BUF / sizeof(lgGpioReport_t))

#define STACK_SIZE (256*1024)

#define LG_USER_LEN 16
#define LG_SALT_LEN 16

/* File constants
*/

#define LG_FILE_NONE   0
#define LG_FILE_MIN    1
#define LG_FILE_READ   1
#define LG_FILE_WRITE  2
#define LG_FILE_RW     3
#define LG_FILE_APPEND 4
#define LG_FILE_CREATE 8
#define LG_FILE_TRUNC  16
#define LG_FILE_MAX    31

#define LG_FROM_START   0
#define LG_FROM_CURRENT 1
#define LG_FROM_END     2

/* GPIO constants
*/

#define LG_GPIO_LABEL_LEN 32
#define LG_GPIO_NAME_LEN  32
#define LG_GPIO_USER_LEN  32

#define LG_GPIO_IS_KERNEL       GPIOLINE_FLAG_KERNEL
#define LG_GPIO_IS_OUT          GPIOLINE_FLAG_IS_OUT
#define LG_GPIO_IS_ACTIVE_LOW   GPIOLINE_FLAG_ACTIVE_LOW
#define LG_GPIO_IS_OPEN_DRAIN   GPIOLINE_FLAG_OPEN_DRAIN
#define LG_GPIO_IS_OPEN_SOURCE  GPIOLINE_FLAG_OPEN_SOURCE

#define LG_SET_INPUT            GPIOHANDLE_REQUEST_INPUT
#define LG_SET_OUTPUT           GPIOHANDLE_REQUEST_OUTPUT
#define LG_SET_ACTIVE_LOW       GPIOHANDLE_REQUEST_ACTIVE_LOW
#define LG_SET_OPEN_DRAIN       GPIOHANDLE_REQUEST_OPEN_DRAIN
#define LG_SET_OPEN_SOURCE      GPIOHANDLE_REQUEST_OPEN_SOURCE

#define LG_RISING_EDGE          GPIOEVENT_REQUEST_RISING_EDGE
#define LG_FALLING_EDGE         GPIOEVENT_REQUEST_FALLING_EDGE
#define LG_BOTH_EDGES           GPIOEVENT_REQUEST_BOTH_EDGES

#define LG_LOW 0
#define LG_HIGH 1
#define LG_TIMEOUT 2

#define LG_TX_PWM 0
#define LG_TX_WAVE 1

#define LG_MAX_MICS_DEBOUNCE   5000000 /* 5 seconds */
#define LG_MAX_MICS_WATCHDOG 300000000 /* 5 minutes */

/* Script constants
*/

#define LG_MAX_MICS_DELAY   5e6 /* 5 seconds */
#define LG_MAX_MILS_DELAY 300e6 /* 5 minutes */

/* script status
*/

#define LG_SCRIPT_INITING 0
#define LG_SCRIPT_READY   1
#define LG_SCRIPT_RUNNING 2
#define LG_SCRIPT_WAITING 3
#define LG_SCRIPT_EXITED  4
#define LG_SCRIPT_ENDED   5
#define LG_SCRIPT_HALTED  6
#define LG_SCRIPT_FAILED  7

/* SPI constants
*/

#define LG_MAX_SPI_DEVICE_COUNT (1<<16)

/* I2C constants
*/

/* max lgI2cMsg_t per transaction */

#define  LG_I2C_RDRW_IOCTL_MAX_MSGS 42

#define LG_MAX_I2C_DEVICE_COUNT (1<<16)
#define LG_MAX_I2C_ADDR 0x7F

/* i2cZip commands */

#define LG_I2C_END          0
#define LG_I2C_ESC          1
#define LG_I2C_ADDR         2
#define LG_I2C_FLAGS        3
#define LG_I2C_READ         4
#define LG_I2C_WRITE        5

/* types
*/

typedef struct lgChipInfo_s
{
   uint32_t lines;
   char name[LG_GPIO_NAME_LEN];   /* Linux name */
   char label[LG_GPIO_LABEL_LEN]; /* functional name */
} lgChipInfo_t, *lgChipInfo_p;

typedef struct
{
   uint16_t state;
   int      fd;
   int      pipe_number;
   int      max_emits;
} lgNotify_t;

typedef void (*callbk_t) ();

typedef struct
{
   uint64_t timestamp; /* alert time in nanoseconds*/
   uint8_t chip; /* gpiochip device number */
   uint8_t gpio; /* offset into gpio device */
   uint8_t level; /* 0=low, 1=high, 2=watchdog */
   uint8_t flags; /* none defined, ignore report if non-zero */
} lgGpioReport_t;

typedef struct lgGpioAlert_s
{
   lgGpioReport_t report;
   int nfyHandle;
} lgGpioAlert_t, *lgGpioAlert_p;

typedef struct lgLineInfo_s
{
   uint32_t offset;               /* GPIO number */
   uint32_t lFlags;
   char name[LG_GPIO_NAME_LEN];   /* GPIO name */
   char user[LG_GPIO_USER_LEN];   /* user */
} lgLineInfo_t, *lgLineInfo_p;

typedef struct lgPulse_s
{
   uint64_t bits;
   uint64_t mask;
   int64_t delay;
} lgPulse_t, *lgPulse_p;

typedef struct
{
   uint16_t addr;  /* slave address       */
   uint16_t flags;
   uint16_t len;   /* msg length          */
   uint8_t  *buf;  /* pointer to msg data */
} lgI2cMsg_t;



typedef void (*lgGpioAlertsFunc_t)  (int           num_alerts,
                                    lgGpioAlert_p alerts,
                                    void          *userdata);

typedef void *(lgThreadFunc_t) (void *);


/* semi-private prototypes
*/

const char *lguGetConfigDir(void);
void lguSetConfigDir(const char *dirPath);
int lgGpioSetBannedState(int handle, int gpio, int banned);

/* GPIO chip API
*/

/*F*/
int lgGpiochipOpen(int gpioDev);
/*D
This returns a handle to a gpiochip device.

. .
gpioDev: >= 0
. .

If OK returns a handle (>= 0).

On failure returns a negative error code.

...
h = lgGpiochipOpen(0); // open /dev/gpiochip0

if (h >= 0)
{
   // open ok
}
else
{
   // open error
}
...
D*/

/*F*/
int lgGpiochipClose(int handle);
/*D
This closes an opened gpiochip device.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
. .

If OK returns 0.

On failure returns a negative error code.

...
status = lgGpiochipClose(h); // close gpiochip

if (status < 0)
{
   // close failed
}
...
D*/

/*F*/
int lgGpioGetChipInfo(int handle, lgChipInfo_p chipInfo);
/*D
This returns information about a gpiochip.

. .
  handle: >= 0 (as returned by [*lgGpiochipOpen*])
chipInfo: A pointer to space for a lgChipInfo_t object
. .

If OK returns 0 and updates chipInfo.

On failure returns a negative error code.

This command gets the number of GPIO on the gpiochip,
its name, and its usage.

...
lgChipInfo_t cInfo;

status = lgGpioGetChipInfo(h, &cInfo);

if (status == LG_OKAY)
{
   printf("lines=%d name=%s label=%s\n",
      cInfo.lines, cInfo.name, cInfo.label))
}
...
D*/


/*F*/
int lgGpioGetLineInfo(int handle, int gpio, lgLineInfo_p lineInfo);
/*D
Returns information about a GPIO.

. .
  handle: >= 0 (as returned by [*lgGpiochipOpen*])
    gpio: >= 0, as legal for the gpiochip
lineInfo: A pointer to space for a lgLineInfo_t object
. .

If OK returns 0 and updates lineInfo.

On failure returns a negative error code.

This command gets information for a GPIO of a gpiochip.
In particular it gets the GPIO number, kernel usage flags,
its user, and its purpose.

The usage flags are bits.

Bit @ value @ Bit meaning
0   @  1    @ GPIO in use by the kernel
1   @  2    @ GPIO is an output
2   @  4    @ GPIO is active low
3   @  8    @ GPIO is open drain
4   @ 16    @ GPIO is open source

The user and purpose fields are filled in by the software which has
claimed the GPIO and may be blank.

...
lgLineInfo_t lInfo;

status = lgGpioGetLineInfo(h, gpio, &lInfo);

if (status == LG_OKAY)
{
   printf("lFlags=%d name=%s user=%s\n",
      lInfo.lines, lInfo.name, lInfo.user))
}
...
D*/


/*F*/
int lgGpioGetMode(int handle, int gpio);
/*D
Returns the GPIO mode.

. .
  handle: >= 0 (as returned by [*lgGpiochipOpen*])
    gpio: >= 0, as legal for the gpiochip
. .

If OK returns the GPIO mode.

On failure returns a negative error code.

Mode bit @ Value @ Meaning
0        @  1    @ Kernel: In use by the kernel
1        @  2    @ Kernel: Output
2        @  4    @ Kernel: Active low
3        @  8    @ Kernel: Open drain
4        @ 16    @ Kernel: Open source
5        @ 32    @ Kernel: ---
6        @ 64    @ Kernel: ---
7        @ 128   @ Kernel: ---
8        @ 256   @ LG: Input
9        @ 512   @ LG: Output
10       @ 1024  @ LG: Alert
11       @ 2048  @ LG: Group
12       @ 4096  @ LG: ---
13       @ 8192  @ LG: ---
14       @ 16384 @ LG: ---
15       @ 32768 @ LG: ---
D*/


/*F*/
int lgGpioSetUser(int handle, const char *gpiouser);
/*D
This sets the user string to be associated with each claimed GPIO.

. .
  handle: >= 0 (as returned by [*lgGpiochipOpen*])
gpiouser: a string up to 32 characters long
. .

If OK returns 0.

On failure returns a negative error code.

...
status = lgGpioSetUser(h, "my_title");
...
D*/


/*F*/
int lgGpioClaimInput(int handle, int lFlags, int gpio);
/*D
This claims a GPIO for input.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
lFlags: line flags for the GPIO
  gpio: the GPIO to be claimed
. .

If OK returns 0.

On failure returns a negative error code.

The line flags may be used to set the GPIO
as active low, open drain, or open source.

...
// open GPIO 23 for input
status = lgGpioClaimInput(h, 0, 23);
...
D*/


/*F*/
int lgGpioClaimOutput(int handle, int lFlags, int gpio, int level);
/*D
This claims a GPIO for output.
. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
lFlags: line flags for the GPIO
  gpio: the GPIO to be claimed
 level: the initial level to set for the GPIO
. .

If OK returns 0.

On failure returns a negative error code.

The line flags may be used to set the GPIO
as active low, open drain, or open source.

If level is zero the GPIO will be initialised low.  If any other
value is used the GPIO will be initialised high.

...
// open GPIO 31 for high output
status = lgGpioClaimOutput(h, 0, 31, 1);
...
D*/


/*F*/
int lgGpioClaimAlert(
   int handle, int lFlags, int eFlags, int gpio, int nfyHandle);
/*D
This claims a GPIO for alerts on level changes.

. .
   handle: >= 0 (as returned by [*lgGpiochipOpen*])
   lFlags: line flags for the GPIO
   eFlags: event flags for the GPIO
     gpio: >= 0, as legal for the gpiochip
nfyHandle: >= 0 (as returned by [*lgNotifyOpen*])
. .

If OK returns 0.

On failure returns a negative error code.

The line flags may be used to set the GPIO
as active low, open drain, or open source.

The event flags are used to specify alerts for a rising edge,
falling edge, or both edges.

The alerts will be sent to a previously opened notification. If
you don't want them sent to a notification set nfyHandle to -1.

The alerts will also be sent to any callback registered for the
GPIO by [*lgGpioSetAlertsFunc*].

All GPIO alerts are also sent to a callback registered by
[*lgGpioSetSamplesFunc*].

...
status = lgGpioClaimAlert(h, 0, LG_BOTH_EDGES, 16, -1);
...
D*/

/*F*/
int lgGpioFree(int handle, int gpio);
/*D
This frees a GPIO.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
  gpio: the GPIO to be freed
. .

If OK returns 0.

On failure returns a negative error code.

The GPIO may now be claimed by another user or for a different purpose.

...
status = lgGpioFree(h, 16);
...
D*/


/*F*/
int lgGroupClaimInput(
   int handle, int lFlags, int count, const int *gpios);
/*D
This claims a group of GPIO for inputs.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
lFlags: line flags for the GPIO group
 count: the number of GPIO to claim
 gpios: the group GPIO
. .

If OK returns 0.

On failure returns a negative error code.

The line flags may be used to set the group
as active low, open drain, or open source.

gpios is an array of one or more GPIO.  The first GPIO is
called the group leader and is used to reference the group as a whole.

...
int buttons[4] = {9, 7, 2, 6};

status = lgGroupClaimInput(h, 0, 4, buttons);

if (status == LG_OKAY)
{
   // OK
}
else
{
   // Error
}
...
D*/


/*F*/
int lgGroupClaimOutput(
   int handle, int lFlags, int count, const int *gpios, const int *levels);
/*D
This claims a group of GPIO for outputs.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
lFlags: line flags for the GPIO group
 count: the number of GPIO to claim
 gpios: the group GPIO
levels: the initial level for each GPIO
. .

If OK returns 0.

On failure returns a negative error code.

The line flags may be used to set the group
as active low, open drain, or open source.

gpios is an array of one or more GPIO.  The first GPIO is
called the group leader and is used to reference the group as a whole.

levels is an array of initialisation values for the GPIO. If a value is
zero the corresponding GPIO will be initialised low.  If any other
value is used the corresponding GPIO will be initialised high.

...
int leds[7] =   {15, 16, 17, 8, 12, 13, 14};
int levels[7] = { 1,  0,  1, 1,  1,  0,  0};

status = lgGroupClaimInput(h, 0, 7, leds, levels);

if (status == LG_OKAY)
{
   // OK
}
else
{
   // Error
}
...
D*/

/*F*/
int lgGroupFree(int handle, int gpio);
/*D
This frees all the GPIO associated with a group.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
  gpio: the group to be freed
. .

If OK returns 0.

On failure returns a negative error code.

The GPIO may now be claimed by another user or for a different purpose.

...
status = lgGroupFree(9); // free buttons
...
D*/


/*F*/
int lgGpioRead(int handle, int gpio);
/*D
This returns the level of a GPIO.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
  gpio: the GPIO to be read
. .

If OK returns 0 (low) or 1 (high).

On failure returns a negative error code.

This command will work for any claimed GPIO (even if a member
of a group).  For an output GPIO the value returned
will be that last written to the GPIO.

...
level = lgGpioRead(h, 15); // get level of GPIO 15
...
D*/


/*F*/
int lgGpioWrite(int handle, int gpio, int level);
/*D
This sets the level of an output GPIO.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
  gpio: the GPIO to be written
 level: the level to set
. .

If OK returns 0.

On failure returns a negative error code.

This command will work for any GPIO claimed as an output
(even if a member of a group).

If level is zero the GPIO will be set low (0).
If any other value is used the GPIO will be set high (1).

...
status = lgGpioWrite(h, 23, 1); // set GPIO 23 high
...
D*/


/*F*/
int lgGroupRead(int handle, int gpio, uint64_t *groupBits);
/*D
This returns the levels read from a group.

. .
   handle: >= 0 (as returned by [*lgGpiochipOpen*])
     gpio: the group to be read
groupBits: a pointer to a 64-bit memory area for the returned levels
. .

If OK returns the group size and updates groupBits.

On failure returns a negative error code.

This command will work for an output group as well as an input
group.  For an output group the value returned
will be that last written to the group GPIO.

Note that this command will also work on an individual GPIO claimed
as an input or output as that is treated as a group with one member.

After a successful read groupBits is set as follows.

Bit 0 is the level of the group leader. 
Bit 1 is the level of the second GPIO in the group. 
Bit x is the level of GPIO x+1 of the group.

...
// assuming a read group of 4 buttons: 9, 7, 2, 6.
uint64_t bits;

size = lgGroupRead(h, 9, &bits); // 9 is buttons group leader

if (size >= 0) // size of group is returned so size will be 4
{
   level_9 = (bits >> 0) & 1;
   level_7 = (bits >> 1) & 1;
   level_2 = (bits >> 2) & 1;
   level_6 = (bits >> 3) & 1;
}
else
{
   // error
}
...

D*/


/*F*/
int lgGroupWrite(
   int handle, int gpio, uint64_t groupBits, uint64_t groupMask);
/*D
This sets the levels of an output group.

. .
   handle: >= 0 (as returned by [*lgGpiochipOpen*])
     gpio: the group to be written
groupBits: the level to set if the corresponding bit in groupMask is set
groupMask: a mask indicating the group GPIO to be updated
. .

If OK returns 0.

On failure returns a negative error code.

The values of each GPIO of the group are set according to the bits 
of groupBits.

Bit 0 sets the level of the group leader. 
Bit 1 sets the level of the second GPIO in the group. 
Bit x sets the level of GPIO x+1 in the group.

However this may be modified by the groupMask.  A GPIO is only
updated if the corresponding bit in the mask is 1.

...
// assuming an output group of 7 LEDs: 15, 16, 17, 8, 12, 13, 14.

// switch on all LEDs
status = lgGroupWrite(h, 15, 0x7f, 0x7f);

// switch off all LEDs
status = lgGroupWrite(h, 15, 0x00, 0x7f);

// switch on first 4 LEDs, leave others unaltered
status = lgGroupWrite(h, 15, 0x0f, 0x0f);

// switch on LED attached to GPIO 13, leave others unaltered
status = lgGroupWrite(h, 15, 32, 32);
...
D*/


/*F*/
int lgTxPulse(
   int handle,
   int gpio,
   int pulseOn,
   int pulseOff,
   int pulseOffset,
   int pulseCycles);
/*D
This starts software timed pulses on an output GPIO.

. .
     handle: >= 0 (as returned by [*lgGpiochipOpen*])
       gpio: the GPIO to be written
    pulseOn: pulse high time in microseconds
   pulseOff: pulse low time in microseconds
pulseOffset: offset from nominal pulse start position
pulseCycles: the number of pulses to be sent, 0 for infinite
. .

If OK returns the number of entries left in the PWM queue for the GPIO.

On failure returns a negative error code.

If both pulseOn and pulseOff are zero pulses will be switched off
for that GPIO.  The active pulse, if any, will be stopped and any
queued pulses will be deleted.

Each successful call to this function consumes one PWM queue entry.

pulseCycles cycles are transmitted (0 means infinite).  Each cycle
consists of pulseOn microseconds of GPIO high followed by pulseOff
microseconds of GPIO low.

PWM is characterised by two values, its frequency (number of cycles
per second) and its duty cycle (percentage of high time per cycle).

The set frequency will be 1000000 / (pulseOn + pulseOff) Hz.

The set duty cycle will be pulseOn / (pulseOn + pulseOff) * 100 %.

E.g. if pulseOn is 50 and pulseOff is 100 the frequency will be 6666.67 Hz
and the duty cycle will be 33.33 %.

pulseOffset is a microsecond offset from the natural start of the PWM cycle.

For instance if the PWM frequency is 10 Hz the natural start of each cycle
is at seconds 0, then 0.1, 0.2, 0.3 etc.  In this case if the offset is
20000 microseconds the cycle will start at seconds 0.02, 0.12, 0.22, 0.32 etc.

Another pulse command may be issued to the GPIO before the last has finished.

If the last pulse had infinite cycles then it will be replaced by
the new settings at the end of the current cycle. Otherwise it will
be replaced by the new settings when all its cycles are compete.

Multiple pulse settings may be queued in this way.

...
slots_left = lgTxPulse(h,  8, 100000, 100000, 0, 0); // flash LED at 5 Hz

slots_left = lgTxPulse(h, 30, 1500, 18500, 0, 0); // move servo to centre

slots_left = lgTxPulse(h, 30, 2000, 18000, 0, 0); // move servo clockwise
...
D*/

/*F*/
int lgTxPwm(
   int handle,
   int gpio,
   float pwmFrequency,
   float pwmDutyCycle,
   int pwmOffset,
   int pwmCycles);
/*D
This starts software timed PWM on an output GPIO.

. .
      handle: >= 0 (as returned by [*lgGpiochipOpen*])
        gpio: the GPIO to be pulsed
pwmFrequency: PWM frequency in Hz (0=off, 0.1-10000)
pwmDutyCycle: PWM duty cycle in % (0-100)
   pwmOffset: offset from nominal pulse start position
   pwmCycles: the number of pulses to be sent, 0 for infinite
. .

If OK returns the number of entries left in the PWM queue for the GPIO.

On failure returns a negative error code.

Each successful call to this function consumes one PWM queue entry.

PWM is characterised by two values, its frequency (number of cycles
per second) and its duty cycle (percentage of high time per cycle).

Another PWM command may be issued to the GPIO before the last has finished.

If the last pulse had infinite cycles then it will be replaced by
the new settings at the end of the current cycle. Otherwise it will
be replaced by the new settings when all its cycles are complete.

Multiple PWM settings may be queued in this way.
D*/

/*F*/
int lgTxServo(
   int handle,
   int gpio,
   int pulseWidth,
   int servoFrequency,
   int servoOffset,
   int servoCycles);
/*D
This starts software timed servo pulses on an output GPIO.

I would only use software timed servo pulses for testing purposes.  The
timing jitter will cause the servo to fidget.  This may cause it to
overheat and wear out prematurely.

. .
        handle: >= 0 (as returned by [*lgGpiochipOpen*])
          gpio: the GPIO to be pulsed
    pulseWidth: pulse high time in microseconds (0=off, 500-2500)
servoFrequency: the number of pulses per second (40-500).
   servoOffset: offset from nominal pulse start position
   servoCycles: the number of pulses to be sent, 0 for infinite
. .

If OK returns the number of entries left in the PWM queue for the GPIO.

On failure returns a negative error code.

Each successful call to this function consumes one PWM queue entry.

Another servo command may be issued to the GPIO before the last
has finished.

If the last pulse had infinite cycles then it will be replaced by
the new settings at the end of the current cycle. Otherwise it will
be replaced by the new settings when all its cycles are compete.

Multiple servo settings may be queued in this way.
D*/


/*F*/
int lgTxWave(
   int handle, int gpio, int count, lgPulse_p pulses);
/*D
This starts a wave on an output group of GPIO.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
  gpio: the group leader
 count: the number of pulses in the wave
pulses: the pulses
. .

If OK returns the number of entries left in the wave queue for the group.

On failure returns a negative error code.

Each successful call to this function consumes one queue entry.

This command starts a wave of pulses.

pulses is an array of pulses to be transmitted on the group.

Each pulse is defined by the following triplet:

bits:  the levels to set for the selected GPIO 
mask:  the GPIO to select 
delay: the delay in microseconds before the next pulse

Another wave command may be issued to the group before the
last has finished transmission. The new wave will start when
the previous wave has competed.

Multiple waves may be queued in this way.

...
#include <stdio.h>

#include <lgpio.h>

#define PULSES 2000

int main(int argc, char *argv[])
{
   int GPIO[] =   {16, 17, 18, 19, 20, 21};
   int levels[] = { 1,  1,  1,  1,  1,  1};
   int h;
   int e;
   int mask;
   int delay;
   int p;
   lgPulse_t pulses[PULSES];

   h = lgGpiochipOpen(0); // open /dev/gpiochip0

   if (h < 0) { printf("ERROR: %s (%d)\n", lguErrorText(h), h); return 1; }

   e =  lgGroupClaimOutput(h, 0, 6, GPIO, levels);

   if (e < 0) { printf("ERROR: %s (%d)\n", lguErrorText(e), e); return 1; }

   mask = 0;
   p = 0;

   for (p=0; p<PULSES; p++)
   {
      pulses[p].bits = (p+1)>>2;  // see what sort of pattern we get
      pulses[p].mask = mask;      // with bits and mask changing
      pulses[p].delay = (PULSES + 500) - p;

      if (++mask > 0x3f) mask = 0;
   }

   lgTxWave(h, GPIO[0], p, pulses);

   while (lgTxBusy(h, GPIO[0], LG_TX_WAVE)) lguSleep(0.1);

   lgGpiochipClose(h);
}
...
D*/

/*F*/
int lgTxBusy(int handle, int gpio, int kind);
/*D
This returns true if transmissions of the specified kind
are active on the GPIO or group.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
  gpio: the gpio or group to be checked
  kind: LG_TX_PWM or LG_TX_WAVE
. .

If OK returns 1 for busy and 0 for not busy.

On failure returns a negative error code.

...
while (lgTxBusy(h, 15, LG_TX_PWM)) // wait for PWM to finish on GPIO 15
   lguSleep(0.1);
...
D*/

/*F*/
int lgTxRoom(int handle, int gpio, int kind);
/*D
This returns the number of entries available for queueing
transmissions of the specified kind on the GPIO or group.

. .
handle: >= 0 (as returned by [*lgGpiochipOpen*])
  gpio: the gpio or group to be checked
  kind: LG_TX_PWM or LG_TX_WAVE
. .

If OK returns the number of free entries (0 if none).

On failure returns a negative error code.

...
while (lgTxRoom(h, 17, LG_TX_WAVE) > 0))
{
   // queue another wave
}
...
D*/

/*F*/
int lgGpioSetDebounce(int handle, int gpio, int debounce_us);
/*D
This sets the debounce time for a GPIO.

. .
     handle: >= 0 (as returned by [*lgGpiochipOpen*])
       gpio: the GPIO to be configured
debounce_us: the debounce time in microseconds
. .

If OK returns 0.

On failure returns a negative error code.

This only affects alerts.

An alert will only be issued if the edge has been stable for at least
debounce microseconds.

Generally this is used to debounce mechanical switches (e.g. contact
bounce).

Suppose that a square wave at 5 Hz is being generated on a GPIO.  Each
edge will last 100000 microseconds.  If a debounce time of 100001
is set no alerts will be generated,  If a debounce time of 99999
is set 10 alerts will be generated per second.

Note that level changes will be timestamped debounce microseconds
after the actual level change.

...
lgSetDebounceTime(h, 16, 1000); // set a millisecond of debounce
...
D*/

/*F*/
int lgGpioSetWatchdog(int handle, int gpio, int watchdog_us);
/*D
This sets the watchdog time for a GPIO.

. .
     handle: >= 0 (as returned by [*lgGpiochipOpen*])
       gpio: the GPIO to be configured
watchdog_us: the watchdog time in microseconds
. .

If OK returns 0.

On failure returns a negative error code.

This only affects alerts.

A watchdog alert will be sent if no edge alert has been issued
for that GPIO in the previous watchdog microseconds.

Note that only one watchdog alert will be sent per stream of
edge alerts.  The watchdog is reset by the sending of a new
edge alert.

The level is set to LG_TIMEOUT (2) for a watchdog alert.

...
lgSetWatchdogTime(h, 17, 200000); // alert if nothing for 0.2 seconds
...
D*/

/*F*/
int lgGpioSetAlertsFunc(
   int handle, int gpio, lgGpioAlertsFunc_t cbf, void *userdata);
/*D
This sets up a callback to be called when an alert
GPIO changes state.

. .
  handle: >= 0 (as returned by [*lgGpiochipOpen*])
    gpio: the GPIO to be monitored
     cbf: the callback function
userdata: a pointer to arbitrary user data
. .

If OK returns 0.

On failure returns a negative error code.

...
#include <stdio.h>
#include <inttypes.h>

#include <lgpio.h>

void afunc(int e, lgGpioAlert_p evt, void *data)
{
   int i;
   int userdata = *(int*)data;

   for (i=0; i<e; i++)
   {
      printf("u=%d t=%"PRIu64" c=%d g=%d l=%d f=%d (%d of %d)\n",
         userdata, evt[i].report.timestamp, evt[i].report.chip,
         evt[i].report.gpio, evt[i].report.level,
         evt[i].report.flags, i+1, e);
   }
}

int main(int argc, char *argv[])
{
   int h;
   int e;
   static int userdata=123;

   h = lgGpiochipOpen(0);

   if (h < 0) { printf("ERROR: %s (%d)\n", lguErrorText(h), h); return 1; }

   lgGpioSetAlertsFunc(h, GPIO, afunc, &userdata);

   e = lgGpioClaimAlert(h, 0, LG_BOTH_EDGES, 23, -1);

   if (e < 0) { printf("ERROR: %s (%d)\n", lguErrorText(e), e); return 1; }

   lguSleep(10);

   lgGpiochipClose(h);
}
...

Assuming square wave at 800 Hz is being received at GPIO 23.

. .
u=123 ts=1602089980691229623 c=0 g=23 l=1 f=0 (1 of 1)
u=123 ts=1602089980691854934 c=0 g=23 l=0 f=0 (1 of 1)
u=123 ts=1602089980692479308 c=0 g=23 l=1 f=0 (1 of 1)
u=123 ts=1602089980693114566 c=0 g=23 l=0 f=0 (1 of 1)
u=123 ts=1602089980693728784 c=0 g=23 l=1 f=0 (1 of 1)
u=123 ts=1602089980694354355 c=0 g=23 l=0 f=0 (1 of 1)
u=123 ts=1602089980694978468 c=0 g=23 l=1 f=0 (1 of 1)
. .
D*/


/*F*/
void lgGpioSetSamplesFunc(lgGpioAlertsFunc_t cbf, void *userdata);
/*D
This sets up a callback to be called when any alert
GPIO changes state.

. .
     cbf: the callback function
userdata: a pointer to arbitrary user data
. .

If OK returns 0.

On failure returns a negative error code.

Note that no handle or gpio is specified.  The callback function will
receive alerts for all gpiochips and gpio.

...
#include <stdio.h>
#include <inttypes.h>

#include <lgpio.h>

void afunc(int e, lgGpioAlert_p evt, void *data)
{
   int i;
   int userdata = *(int*)data;

   for (i=0; i<e; i++)
   {
      printf("u=%d t=%"PRIu64" c=%d g=%d l=%d f=%d (%d of %d)\n",
         userdata, evt[i].report.timestamp, evt[i].report.chip,
         evt[i].report.gpio, evt[i].report.level,
         evt[i].report.flags, i+1, e);
   }
}

int main(int argc, char *argv[])
{
   int h;
   static int userdata=456;

   h = lgGpiochipOpen(0);

   if (h < 0) { printf("ERROR: %s (%d)\n", lguErrorText(h), h); return 1; }

   lgGpioSetSamplesFunc(afunc, &userdata);

   lgGpioClaimAlert(h, 0, LG_BOTH_EDGES, 23, -1);
   lgGpioClaimAlert(h, 0, LG_BOTH_EDGES, 24, -1);
   lgGpioClaimAlert(h, 0, LG_BOTH_EDGES, 25, -1);

   lguSleep(10);

   lgGpiochipClose(h);
}
...

Assuming square wave at 800 Hz is being received at GPIO 23, 24, 25.

. .
u=456 ts=1602090898869011679 c=0 g=24 l=1 f=0 (1 of 3)
u=456 ts=1602090898869016627 c=0 g=25 l=1 f=0 (2 of 3)
u=456 ts=1602090898869627667 c=0 g=23 l=0 f=0 (3 of 3)
u=456 ts=1602090898869636522 c=0 g=24 l=0 f=0 (1 of 3)
u=456 ts=1602090898869641157 c=0 g=25 l=0 f=0 (2 of 3)
u=456 ts=1602090898870252614 c=0 g=23 l=1 f=0 (3 of 3)
u=456 ts=1602090898870261155 c=0 g=24 l=1 f=0 (1 of 3)
u=456 ts=1602090898870266208 c=0 g=25 l=1 f=0 (2 of 3)
u=456 ts=1602090898870879800 c=0 g=23 l=0 f=0 (3 of 3)
u=456 ts=1602090898870890477 c=0 g=24 l=0 f=0 (1 of 3)
u=456 ts=1602090898870895529 c=0 g=25 l=0 f=0 (2 of 3)
u=456 ts=1602090898871503652 c=0 g=23 l=1 f=0 (3 of 3)
. .
D*/

/* Notifications API
*/

void lgNotifyCloseOrphans(int slot, int fd);
int lgNotifyOpenWithSize(int pipeSize);

int  lgNotifyOpenInBand(int fd);

/*F*/
int lgNotifyOpen(void);
/*D
This function requests a free notification.

If OK returns a handle (>= 0).

On failure returns a negative error code.

A notification is a method for being notified of GPIO state changes
via a pipe or socket.

The notification pipes are created in the library working directory
(see [*lguGetWorkDir*]).

Pipe notifications for handle x will be available at the pipe
named .lgd-nfy* (where * is the handle number).  E.g. if the
function returns 15 then the notifications must be read
from .lgd-nfy15.

Socket notifications are returned to the socket which requested the
handle.

...
h = lgNotifyOpen();

if (h >= 0)
{
   sprintf(str, ".lgd-nfy%d", h);

   fd = open(str, O_RDONLY);

   if (fd >= 0)
   {
      // Okay.
   }
   else
   {
      // Error.
   }
}
else
{
   // Error.
}
...
D*/


/*F*/
int lgNotifyResume(int handle);
/*D
This function restarts notifications on a paused notification.

. .
handle: >= 0 (as returned by [*lgNotifyOpen*])
. .

If OK returns 0.

On failure returns a negative error code.

The notification gets state changes for each associated GPIO.

Each notification occupies 16 bytes in the fifo and has the
following structure.

. .
typedef struct
{
   uint64_t timestamp; // alert time in nanoseconds
   uint8_t chip;       // gpiochip device number
   uint8_t gpio;       // offset into gpio device
   uint8_t level;      // 0=low, 1=high, 2=timeout
   uint8_t flags;      // none currently defined
} lgGpioReport_t;
. .

timestamp: the number of nanoseconds since the epoch (start of 1970)
level: indicates the level of the GPIO 
flags: no flags are currently defined

For future proofing it is probably best to ignore any notification
with non-zero flags.

...
// Start notifications for associated GPIO.
lgNotifyResume(h);
...
D*/


/*F*/
int lgNotifyPause(int handle);
/*D
This function pauses notifications.

. .
handle: >= 0 (as returned by [*lgNotifyOpen*])
. .

If OK returns 0.

On failure returns a negative error code.

Notifications are suspended until [*lgNotifyResume*] is called.

...
lgNotifyPause(h);
...
D*/


/*F*/
int lgNotifyClose(int handle);
/*D
This function stops notifications and frees the handle for reuse.

. .
handle: >= 0 (as returned by [*lgNotifyOpen*])
. .

If OK returns 0.

On failure returns a negative error code.

...
lgNotifyClose(h);
...
D*/


/* I2C API
*/

/*F*/
int lgI2cOpen(int i2cDev, int i2cAddr, int i2cFlags);
/*D
This returns a handle for the device at the address on the I2C bus.

. .
  i2cDev: >= 0
 i2cAddr: 0-0x7F
i2cFlags: 0
. .

If OK returns a handle (>= 0).

On failure returns a negative error code.

No flags are currently defined.  This parameter should be set to zero.

For the SMBus commands the low level transactions are shown at the end
of the function description.  The following abbreviations are used.

. .
S      (1 bit) : Start bit
P      (1 bit) : Stop bit
Rd/Wr  (1 bit) : Read/Write bit. Rd equals 1, Wr equals 0
A, NA  (1 bit) : Accept and not accept bit
Addr   (7 bits): I2C 7 bit address
i2cReg (8 bits): Command byte, a byte which often selects a register
Data   (8 bits): A data byte
Count  (8 bits): A byte defining the length of a block operation

[..]: Data sent by the device
. .
D*/


/*F*/
int lgI2cClose(int handle);
/*D
This closes the I2C device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
. .

If OK returns 0.

On failure returns a negative error code.
D*/


/*F*/
int lgI2cWriteQuick(int handle, int bitVal);
/*D
This sends a single bit (in the Rd/Wr bit) to the device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
bitVal: 0-1, the value to write
. .

If OK returns 0.

On failure returns a negative error code.

Quick command. SMBus 2.0 5.5.1
. .
S Addr bit [A] P
. .
D*/


/*F*/
int lgI2cWriteByte(int handle, int byteVal);
/*D
This sends a single byte to the device.

. .
 handle: >= 0 (as returned by [*lgI2cOpen*])
byteVal: 0-0xFF, the value to write
. .

If OK returns 0.

On failure returns a negative error code.

Send byte. SMBus 2.0 5.5.2
. .
S Addr Wr [A] bVal [A] P
. .
D*/


/*F*/
int lgI2cReadByte(int handle);
/*D
This reads a single byte from the device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
. .

If OK returns the byte read (0-255).

On failure returns a negative error code.

Receive byte. SMBus 2.0 5.5.3
. .
S Addr Rd [A] [Data] NA P
. .
D*/


/*F*/
int lgI2cWriteByteData(int handle, int i2cReg, int byteVal);
/*D
This writes a single byte to the specified register of the device.

. .
 handle: >= 0 (as returned by [*lgI2cOpen*])
 i2cReg: 0-255, the register to write
byteVal: 0-0xFF, the value to write
. .

If OK returns 0.

On failure returns a negative error code.

Write byte. SMBus 2.0 5.5.4
. .
S Addr Wr [A] i2cReg [A] bVal [A] P
. .
D*/


/*F*/
int lgI2cWriteWordData(int handle, int i2cReg, int wordVal);
/*D
This writes a single 16 bit word to the specified register of the device.

. .
 handle: >= 0 (as returned by [*lgI2cOpen*])
 i2cReg: 0-255, the register to write
wordVal: 0-0xFFFF, the value to write
. .

If OK returns 0.

On failure returns a negative error code.

Write word. SMBus 2.0 5.5.4
. .
S Addr Wr [A] i2cReg [A] wValLow [A] wValHigh [A] P
. .
D*/


/*F*/
int lgI2cReadByteData(int handle, int i2cReg);
/*D
This reads a single byte from the specified register of the device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
i2cReg: 0-255, the register to read
. .

If OK returns the byte read (0-255).

On failure returns a negative error code.

Read byte. SMBus 2.0 5.5.5
. .
S Addr Wr [A] i2cReg [A] S Addr Rd [A] [Data] NA P
. .
D*/


/*F*/
int lgI2cReadWordData(int handle, int i2cReg);
/*D
This reads a single 16 bit word from the specified register of the device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
i2cReg: 0-255, the register to read
. .

If OK returns the word read (0-65535).

On failure returns a negative error code.

Read word. SMBus 2.0 5.5.5
. .
S Addr Wr [A] i2cReg [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
. .
D*/


/*F*/
int lgI2cProcessCall(int handle, int i2cReg, int wordVal);
/*D
This writes 16 bits of data to the specified register of the device
and reads 16 bits of data in return.

. .
 handle: >= 0 (as returned by [*lgI2cOpen*])
 i2cReg: 0-255, the register to write/read
wordVal: 0-0xFFFF, the value to write
. .

If OK returns the word read (0-65535).

On failure returns a negative error code.

Process call. SMBus 2.0 5.5.6
. .
S Addr Wr [A] i2cReg [A] wValLow [A] wValHigh [A]
   S Addr Rd [A] [DataLow] A [DataHigh] NA P
. .
D*/


/*F*/
int lgI2cWriteBlockData(int handle, int i2cReg, const char *txBuf, int count);
/*D
This writes up to 32 bytes to the specified register of the device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
i2cReg: 0-255, the register to write
 txBuf: an array with the data to send
 count: 1-32, the number of bytes to write
. .

If OK returns 0.

On failure returns a negative error code.

Block write. SMBus 2.0 5.5.7
. .
S Addr Wr [A] i2cReg [A] count [A]
   txBuf0 [A] txBuf1 [A] ... [A] txBufn [A] P
. .
D*/


/*F*/
int lgI2cReadBlockData(int handle, int i2cReg, char *rxBuf);
/*D
This reads a block of up to 32 bytes from the specified register of
the device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
i2cReg: 0-255, the register to read
 rxBuf: an array to receive the read data
. .

The amount of returned data is set by the device.

If OK returns the count of bytes read (0-32) and updates rxBuf.

On failure returns a negative error code.

Block read. SMBus 2.0 5.5.7
. .
S Addr Wr [A] i2cReg [A]
   S Addr Rd [A] [Count] A [rxBuf0] A [rxBuf1] A ... A [rxBufn] NA P
. .
D*/


/*F*/
int lgI2cBlockProcessCall(
   int handle, int i2cReg, char *ioBuf, int count);
/*D
This writes data bytes to the specified register of the device
and reads a device specified number of bytes of data in return.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
i2cReg: 0-255, the register to write/read
 ioBuf: an array with the data to send and to receive the read data
 count: 1-32, the number of bytes to write
. .

If OK returns the count of bytes read (0-32) and updates ioBuf.

On failure returns a negative error code.

The SMBus 2.0 documentation states that a minimum of 1 byte may be
sent and a minimum of 1 byte may be received.  The total number of
bytes sent/received must be 32 or less.

Block write-block read. SMBus 2.0 5.5.8
. .
S Addr Wr [A] i2cReg [A] count [A] ioBuf0 [A] ... ioBufn [A]
   S Addr Rd [A] [Count] A [ioBuf0] A ... [ioBufn] A P
. .
D*/


/*F*/
int lgI2cReadI2CBlockData(int handle, int i2cReg, char *rxBuf, int count);
/*D
This reads count bytes from the specified register of the device.
The count may be 1-32.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
i2cReg: 0-255, the register to read
 rxBuf: an array to receive the read data
 count: 1-32, the number of bytes to read
. .

If OK returns the count of bytes read (0-32) and updates rxBuf.

On failure returns a negative error code.

. .
S Addr Wr [A] i2cReg [A]
   S Addr Rd [A] [rxBuf0] A [rxBuf1] A ... A [rxBufn] NA P
. .
D*/


/*F*/
int lgI2cWriteI2CBlockData(int handle, int i2cReg, const char *txBuf, int count);
/*D
This writes 1 to 32 bytes to the specified register of the device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
i2cReg: 0-255, the register to write
 txBuf: the data to write
 count: 1-32, the number of bytes to write
. .

If OK returns 0.

On failure returns a negative error code.

. .
S Addr Wr [A] i2cReg [A] txBuf0 [A] txBuf1 [A] ... [A] txBufn [A] P
. .
D*/

/*F*/
int lgI2cReadDevice(int handle, char *rxBuf, int count);
/*D
This reads count bytes from the raw device into rxBuf.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
 rxBuf: an array to receive the read data bytes
 count: >0, the number of bytes to read
. .

If OK returns count (>0) and updates rxBuf.

On failure returns a negative error code.

. .
S Addr Rd [A] [rxBuf0] A [rxBuf1] A ... A [rxBufn] NA P
. .
D*/


/*F*/
int lgI2cWriteDevice(int handle, const char *txBuf, int count);
/*D
This writes count bytes from txBuf to the raw device.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
 txBuf: an array containing the data bytes to write
 count: >0, the number of bytes to write
. .

If OK returns 0.

On failure returns a negative error code.

. .
S Addr Wr [A] txBuf0 [A] txBuf1 [A] ... [A] txBufn [A] P
. .
D*/

/*F*/
int lgI2cSegments(int handle, lgI2cMsg_t *segs, int count);
/*D
This function executes multiple I2C segments in one transaction by
calling the I2C_RDWR ioctl.

. .
handle: >= 0 (as returned by [*lgI2cOpen*])
  segs: an array of I2C segments
 count: >0, the number of I2C segments
. .

If OK returns the number of segments executed.

On failure returns a negative error code.
D*/

/*F*/
int lgI2cZip(
   int handle, const char *txBuf, int txCount, char *rxBuf, int rxCount);
/*D
This function executes a sequence of I2C operations.  The
operations to be performed are specified by the contents of txBuf
which contains the concatenated command codes and associated data.

. .
  handle: >= 0 (as returned by [*lgI2cOpen*])
   txBuf: pointer to the concatenated I2C commands, see below
 txCount: size of command buffer
   rxBuf: pointer to buffer to hold returned data
 rxCount: size of receive buffer
. .

If OK returns the count of bytes read (which may be 0) and updates rxBuf.

On failure returns a negative error code.

The following command codes are supported:

Name    @ Cmd & Data @ Meaning
End     @ 0          @ No more commands
Escape  @ 1          @ Next P is two bytes
Address @ 2 P        @ Set I2C address to P
Flags   @ 3 lsb msb  @ Set I2C flags to lsb + (msb << 8)
Read    @ 4 P        @ Read P bytes of data
Write   @ 5 P ...    @ Write P bytes of data

The address, read, and write commands take a parameter P.
Normally P is one byte (0-255).  If the command is preceded by
the Escape command then P is two bytes (0-65535, least significant
byte first).

The address defaults to that associated with the handle.
The flags default to 0.  The address and flags maintain their
previous value until updated.

The returned I2C data is stored in consecutive locations of rxBuf.

...
Set address 0x53, write 0x32, read 6 bytes
Set address 0x1E, write 0x03, read 6 bytes
Set address 0x68, write 0x1B, read 8 bytes
End

2 0x53  5 1 0x32  4 6
2 0x1E  5 1 0x03  4 6
2 0x68  5 1 0x1B  4 8
0
...
D*/

/* Serial API
*/

/*F*/
int lgSerialOpen(const char *serDev, int serBaud, int serFlags);
/*D
This function opens a serial device at a specified baud rate
and with specified flags.

. .
  serDev: the serial device to open
 serBaud: the baud rate in bits per second, see below
serFlags: 0
. .

If OK returns a handle (>= 0).

On failure returns a negative error code.

The baud rate must be one of 50, 75, 110, 134, 150,
200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200,
38400, 57600, 115200, or 230400.

No flags are currently defined.  This parameter should be set to zero.
D*/


/*F*/
int lgSerialClose(int handle);
/*D
This function closes the serial device.

. .
handle: >= 0 (as returned by [*lgSerialOpen*])
. .

If OK returns 0.

On failure returns a negative error code.
D*/

/*F*/
int lgSerialWriteByte(int handle, int byteVal);
/*D
This function writes the byte to the serial device.

. .
 handle: >= 0 (as returned by [*lgSerialOpen*])
byteVal: the byte to write.
. .

If OK returns 0.

On failure returns a negative error code.
D*/

/*F*/
int lgSerialReadByte(int handle);
/*D
This function reads a byte from the serial device.

. .
handle: >= 0 (as returned by [*lgSerialOpen*])
. .

If OK returns the byte read (0-255).

On failure returns a negative error code.
D*/

/*F*/
int lgSerialWrite(int handle, const char *txBuf, int count);
/*D
This function writes count bytes from txBuf to the the serial device.

. .
handle: >= 0 (as returned by [*lgSerialOpen*])
 txBuf: the array of bytes to write
 count: the number of bytes to write
. .

If OK returns 0.

On failure returns a negative error code.
D*/


/*F*/
int lgSerialRead(int handle, char *rxBuf, int count);
/*D
This function reads up count bytes from the the serial device
and writes them to rxBuf.

. .
handle: >= 0 (as returned by [*lgSerialOpen*])
 rxBuf: an array to receive the read data
 count: the maximum number of bytes to read
. .

If OK returns the count of bytes read (>= 0) and updates rxBuf.

On failure returns a negative error code.

D*/


/*F*/
int lgSerialDataAvailable(int handle);
/*D
This function returns the count of bytes available
to be read from the device.

. .
handle: >= 0 (as returned by [*lgSerialOpen*])
. .

If OK returns the count of bytes available(>= 0).

On failure returns a negative error code.
D*/

/* SPI API
*/

/*F*/
int lgSpiOpen(int spiDev, int spiChan, int spiBaud, int spiFlags);
/*D
This function returns a handle for the SPI device on the channel.

. .
  spiDev: >= 0
 spiChan: >= 0
 spiBaud: the SPI speed to set in bits per second
spiFlags: see below
. .

If OK returns a handle (>= 0).

On failure returns a negative error code.

The flags may be used to modify the default behaviour.

spiFlags consists of the least significant 2 bits.

. .
1  0
m  m
. .

mm defines the SPI mode.

. .
Mode POL PHA
 0    0   0
 1    0   1
 2    1   0
 3    1   1
. .

The other bits in flags should be set to zero.
D*/

/*F*/
int lgSpiClose(int handle);
/*D
This functions closes the SPI device.

. .
handle: >= 0 (as returned by [*lgSpiOpen*])
. .

If OK returns 0.

On failure returns a negative error code.
D*/


/*F*/
int lgSpiRead(int handle, char *rxBuf, int count);
/*D
This function reads count bytes of data from the SPI
device.

. .
handle: >= 0 (as returned by [*lgSpiOpen*])
 rxBuf: an array to receive the read data bytes
 count: the number of bytes to read
. .

If OK returns the count of bytes read and updates rxBuf.

On failure returns a negative error code.
D*/


/*F*/
int lgSpiWrite(int handle, const char *txBuf, int count);
/*D
This function writes count bytes of data from txBuf to the SPI
device.

. .
handle: >= 0 (as returned by [*lgSpiOpen*])
 txBuf: the data bytes to write
 count: the number of bytes to write
. .

If OK returns the count of bytes written.

On failure returns a negative error code.
D*/

/*F*/
int lgSpiXfer(int handle, const char *txBuf, char *rxBuf, int count);
/*D
This function transfers count bytes of data from txBuf to the SPI
device.  Simultaneously count bytes of
data are read from the device and placed in rxBuf.

. .
handle: >= 0 (as returned by [*lgSpiOpen*])
 txBuf: the data bytes to write
 rxBuf: the received data bytes
 count: the number of bytes to transfer
. .

If OK returns the count of bytes transferred and updates rxBuf.

On failure returns a negative error code.
D*/


/* Threads API
*/

/*F*/
pthread_t *lgThreadStart(lgThreadFunc_t f, void *userdata);
/*D
Starts a new thread of execution with f as the main routine.

. .
       f: the main function for the new thread
userdata: a pointer to arbitrary user data
. .

If OK returns a pointer to a pthread_t.

On failure returns NULL.

The function is passed the single argument arg.

The thread can be cancelled by passing the pointer to pthread_t to
[*lgThreadStop*].

...
#include <stdio.h>
#include <unistd.h>
#include <lgpio.h>

void *myfunc(void *arg)
{
   while (1)
   {
      printf("%s\n", (char *)arg);
      sleep(1);
   }
}

int main(int argc, char *argv[])
{
   pthread_t *p1, *p2, *p3;

   p1 = lgThreadStart(myfunc, "thread 1"); sleep(3);

   p2 = lgThreadStart(myfunc, "thread 2"); sleep(3);

   p3 = lgThreadStart(myfunc, "thread 3"); sleep(3);

   lgThreadStop(p3); sleep(3);

   lgThreadStop(p2); sleep(3);

   lgThreadStop(p1); sleep(3);
}
...
D*/


/*F*/
void lgThreadStop(pthread_t *pth);
/*D
Cancels the thread pointed at by pth.

. .
pth: a thread pointer (as returned by [*lgThreadStart*])
. .

No value is returned.

The thread to be stopped should have been started with [*lgThreadStart*].
D*/
   
/*F*/
uint64_t lguTimestamp(void);
/*D
Returns the current timestamp.

The timestamp is the number of nanoseconds since the epoch (start
of 1970).
D*/

/*F*/
double lguTime(void);
/*D
Returns the current time.

The time is the number of seconds since the epoch (start
of 1970).
D*/

/*F*/
void lguSleep(double sleepSecs);
/*D
Sleeps for the specified number of seconds.

. .
sleepSecs: how long to sleep in seconds
. .
D*/


/*F*/
int lguSbcName(char *rxBuf, int count);
/*D
Copies the host name of the machine running the lgpio library
to the supplied buffer.  Up to count characters are copied.

. .
rxBuf: a buffer to receive the host name
count: the size of the rxBuf
. .

If OK returns the count of bytes copied and updates rxBuf.

On failure returns a negative error code.
D*/

/*F*/
int lguVersion(void);
/*D
Returns the lgpiolibrary version number.
D*/

/*F*/
int lguGetInternal(int cfgId, uint64_t *cfgVal);
/*D
Get an internal configuration value.

. .
 cfgId: the item.
cfgVal: a variable to receive the returned value
. .

If OK returns 0 and updates cfgVal.

On failure returns a negative error code.
D*/

/*F*/
int lguSetInternal(int cfgId, uint64_t cfgVal);
/*D
Set an internal configuration value.

. .
 cfgId: the item
cfgVal: the value to set
. .

If OK returns 0.

On failure returns a negative error code.
D*/

/*F*/
const char *lguErrorText(int error);
/*D
Returns the error text for an error code.

. .
error: the error code
. .
D*/

/*F*/
void lguSetWorkDir(const char *dirPath);
/*D
Sets the library working directory.

This function has no affect if the working directory has already
been set.

. .
dirPath: the directory to set as the working directory
. .

If dirPath does not start with a / the directory is relative to
the library launch directory.
D*/

/*F*/
const char *lguGetWorkDir(void);
/*D
Returns the library working directory.
D*/

#ifdef __cplusplus
}
#endif

/*PARAMS

bitVal::
A value of 0 or 1.

byteVal:: 0-255
An 8-bit byte value.

cbf::
An alerts callback function.

cfgId::
A number identifying a configuration item.

. .
LG_CFG_ID_DEBUG_LEVEL 0
LG_CFG_ID_MIN_DELAY   1
. .

cfgVal::
The value of a configuration item.

*cfgVal::
The value of a configuration item.

char::
A single character, an 8 bit quantity able to store 0-255.

chipInfo::
A pointer to a lgChipInfo_t object.

count::
The number of items.

debounce_us::
The debounce time in microseconds.

*dirPath::
A directory path which.

double::
A floating point number.

eFlags::

The type of GPIO edge to generate an alert.  See [*lgGpioClaimAlert*].

. .
LG_RISING_EDGE
LG_FALLING_EDGE
LG_BOTH_EDGES
. .

error::
An error code.  All error codes are negative.

f::
A function.

float::
A floating point number

gpio::
A GPIO number, the offset of the GPIO from the base of the gpiochip.
Offsets start at 0.

gpioDev :: >= 0
The device number of a gpiochip.

*gpios::
An array of GPIO numbers.

*gpiouser::
A string of up to 32 characters denoting the user of a GPIO.

groupBits::
A 64-bit value used to set the levels of a group.

Set bit x to set GPIO x of the group high.

Clear bit x to set GPIO x of the group low.

*groupBits::
A 64-bit value denoting the levels of a group.

If bit x is set then GPIO x of the group is high.

groupMask::
A 64-bit value used to determine which members of a group
should be updated.

Set bit x to update GPIO x of the group.

Clear bit x to leave GPIO x of the group unaltered.

handle:: >= 0

A number referencing an object opened by one of

[*lgGpiochipOpen*] 
[*lgI2cOpen*] 
[*lgNotifyOpen*] 
[*lgSerialOpen*] 
[*lgSpiOpen*]

i2cAddr:: 0-0x7F
The address of a device on the I2C bus.

i2cDev::>= 0
An I2C device number.

i2cFlags::0
Flags which modify an I2C open command.  None are currently defined.

i2cReg:: 0-255
A register of an I2C device.

int::
A whole number, negative or positive.

*ioBuf::
A pointer to a buffer used to hold data to send and the data received.

kind:: LG_TX_PWM or LG_TX_WAVE
A type of transmission: PWM or wave.

level::
A GPIO level (0 or 1).

*levels::
An array of GPIO levels.

lFlags::

line flags for the GPIO.

The following values may be or'd to form the value.

. .
LG_SET_ACTIVE_LOW
LG_SET_OPEN_DRAIN
LG_SET_OPEN_SOURCE
. .

lgChipInfo_p::
A pointer to a lgChipInfo_t object.

. .
typedef struct lgChipInfo_s
{
   uint32_t lines;                // number of GPIO
   char name[LG_GPIO_NAME_LEN];   // Linux name
   char label[LG_GPIO_LABEL_LEN]; // functional name
} lgChipInfo_t, *lgChipInfo_p;
. .

lgGpioAlert_t::

. .
typedef struct lgGpioAlert_s
{
   lgGpioReport_t report;
   int nfyHandle;
} lgGpioAlert_t, *lgGpioAlert_p;
. .

See [*lgGpioReport_t*].


lgGpioAlertsFunc_t::

. .
typedef void (*lgGpioAlertsFunc_t)
   (int num_alerts, lgGpioAlert_p alerts, void *userdata);
. .

See [*lgGpioAlert_t*].

lgGpioReport_t::

. .
typedef struct
{
   uint64_t timestamp; // alert time in nanoseconds
   uint8_t chip;       // gpiochip device number
   uint8_t gpio;       // offset into gpio device
   uint8_t level;      // 0=low, 1=high, 2=watchdog
   uint8_t flags;      // none defined, ignore report if non-zero
} lgGpioReport_t;
. .

lgI2cMsg_t::
. .
typedef struct
{
   uint16_t addr;  // slave address
   uint16_t flags;
   uint16_t len;   // msg length
   uint8_t  *buf;  // pointer to msg data
} lgI2cMsg_t;
. .

lgLineInfo_p::
A pointer to a lgLineInfo_t object.

. .
typedef struct lgLine_s
{
   uint32_t offset;               // GPIO number
   uint32_t lFlags;
   char name[LG_GPIO_NAME_LEN];   // GPIO name
   char user[LG_GPIO_USER_LEN];   // user
} lgLineInfo_t, *lgLineInfo_p;
. .

lgPulse_p::
A pointer to a lgPulse_t object.

. .
typedef struct lgPulse_s
{
   uint64_t bits;
   uint64_t mask;
   int64_t delay;
} lgPulse_t, *lgPulse_p;
. .

lgThreadFunc_t::
. .
typedef void *(lgThreadFunc_t) (void *);
. .

lineInfo::
A pointer to a lgLineInfo_t object.

nfyHandle:: >= 0
This associates a notification with a GPIO alert.

*pth::
A thread identifier, returned by [*lgGpioStartThread*].

pthread_t::
A thread identifier.

pulseCycles:: >= 0
The number of PWM pulses to generate.  A value of 0 means infinite.

pulseOff:: >= 0
The off period for a PWM pulse in microseconds.

pulseOffset:: >= 0
The offset in microseconds from the nominal PWM pulse start.

pulseOn:: >= 0
The on period for a PWM pulse in microseconds.

pulses::
An pointer to an array of lgPulse_t objects.

pulseWidth:: 0, 500-2500 microseconds
Servo pulse width

pwmCycles:: >= 0
The number of PWM pulses to generate.  A value of 0 means infinite.

pwmDutyCycle:: 0-100 %
PWM duty cycle %

pwmFrequency:: 0.1-10000 Hz
PWM frequency

pwmOffset:: >= 0
The offset in microseconds from the nominal PWM pulse start.

*rxBuf::
A pointer to a buffer used to receive data.

rxCount::
The size of an input buffer.

*segs::
An array of segments which make up a combined I2C transaction.

serBaud::
The speed of serial communication in bits per second.

*serDev::
The name of a serial tty device, e.g. /dev/ttyAMA0, /dev/ttyUSB0, /dev/tty1.

serFlags::
Flags which modify a serial open command.  None are currently defined.

servoCycles:: >= 0
The number of servo pulses to generate.  A value of 0 means infinite.

servoFrequency:: 40-500 Hz
Servo pulse frequency

servoOffset:: >= 0
The offset in microseconds from the nominal servo pulse start.

sleepSecs:: >= 0.0
The number of seconds to sleep (may be fractional).

spiBaud::
The speed of serial communication in bits per second.

spiChan::
A SPI channel, >= 0.

spiDev::
A SPI device, >= 0.

spiFlags::
See [*lgSpiOpen*].

*txBuf::
An pointer to a buffer of data to transmit.

txCount::
The size of an output buffer.

uint64_t::
A 64-bit unsigned value.

*userdata::
A pointer to arbitrary user data.  This may be used to identify the instance.

You must ensure that the pointer is in scope at the time it is processed.  If
it is a pointer to a global this is automatic.  Do not pass the address of a
local variable.  If you want to pass a transient object then use the
following technique.

In the calling function:

. .
user_type *userdata; 
user_type my_userdata;

userdata = malloc(sizeof(user_type)); 
*userdata = my_userdata;
. .

In the receiving function:

. .
user_type my_userdata = *(user_type*)userdata;

free(userdata);
. .

void::
Denoting no parameter is required.

watchdog_us::
The watchdog time in microseconds.

wordVal:: 0-65535
A 16-bit value.

PARAMS*/

/*DEF_S Error Codes*/

#define LG_OKAY                   0 // No error
#define LG_INIT_FAILED           -1 // initialisation failed
#define LG_BAD_MICROS            -2 // micros not 0-999999
#define LG_BAD_PATHNAME          -3 // can not open pathname
#define LG_NO_HANDLE             -4 // no handle available
#define LG_BAD_HANDLE            -5 // unknown handle
#define LG_BAD_SOCKET_PORT       -6 // socket port not 1024-32000
#define LG_NOT_PERMITTED         -7 // GPIO operation not permitted
#define LG_SOME_PERMITTED        -8 // one or more GPIO not permitted
#define LG_BAD_SCRIPT            -9 // invalid script
#define LG_BAD_TX_TYPE          -10 // bad tx type for GPIO and group
#define LG_GPIO_IN_USE          -11 // GPIO already in use
#define LG_BAD_PARAM_NUM        -12 // script parameter id not 0-9
#define LG_DUP_TAG              -13 // script has duplicate tag
#define LG_TOO_MANY_TAGS        -14 // script has too many tags
#define LG_BAD_SCRIPT_CMD       -15 // illegal script command
#define LG_BAD_VAR_NUM          -16 // script variable id not 0-149
#define LG_NO_SCRIPT_ROOM       -17 // no more room for scripts
#define LG_NO_MEMORY            -18 // can not allocate temporary memory
#define LG_SOCK_READ_FAILED     -19 // socket read failed
#define LG_SOCK_WRIT_FAILED     -20 // socket write failed
#define LG_TOO_MANY_PARAM       -21 // too many script parameters (> 10)
#define LG_SCRIPT_NOT_READY     -22 // script initialising
#define LG_BAD_TAG              -23 // script has unresolved tag
#define LG_BAD_MICS_DELAY       -24 // bad MICS delay (too large)
#define LG_BAD_MILS_DELAY       -25 // bad MILS delay (too large)
#define LG_I2C_OPEN_FAILED      -26 // can not open I2C device
#define LG_SERIAL_OPEN_FAILED   -27 // can not open serial device
#define LG_SPI_OPEN_FAILED      -28 // can not open SPI device
#define LG_BAD_I2C_BUS          -29 // bad I2C bus
#define LG_BAD_I2C_ADDR         -30 // bad I2C address
#define LG_BAD_SPI_CHANNEL      -31 // bad SPI channel
#define LG_BAD_I2C_FLAGS        -32 // bad I2C open flags
#define LG_BAD_SPI_FLAGS        -33 // bad SPI open flags
#define LG_BAD_SERIAL_FLAGS     -34 // bad serial open flags
#define LG_BAD_SPI_SPEED        -35 // bad SPI speed
#define LG_BAD_SERIAL_DEVICE    -36 // bad serial device name
#define LG_BAD_SERIAL_SPEED     -37 // bad serial baud rate
#define LG_BAD_FILE_PARAM       -38 // bad file parameter
#define LG_BAD_I2C_PARAM        -39 // bad I2C parameter
#define LG_BAD_SERIAL_PARAM     -40 // bad serial parameter
#define LG_I2C_WRITE_FAILED     -41 // i2c write failed
#define LG_I2C_READ_FAILED      -42 // i2c read failed
#define LG_BAD_SPI_COUNT        -43 // bad SPI count
#define LG_SERIAL_WRITE_FAILED  -44 // ser write failed
#define LG_SERIAL_READ_FAILED   -45 // ser read failed
#define LG_SERIAL_READ_NO_DATA  -46 // ser read no data available
#define LG_UNKNOWN_COMMAND      -47 // unknown command
#define LG_SPI_XFER_FAILED      -48 // spi xfer/read/write failed
#define LG_BAD_POINTER          -49 // bad (NULL) pointer
#define LG_MSG_TOOBIG           -50 // socket/pipe message too big
#define LG_BAD_MALLOC_MODE      -51 // bad memory allocation mode
#define LG_TOO_MANY_SEGS        -52 // too many I2C transaction segments
#define LG_BAD_I2C_SEG          -53 // an I2C transaction segment failed
#define LG_BAD_SMBUS_CMD        -54 // SMBus command not supported by driver
#define LG_BAD_I2C_WLEN         -55 // bad I2C write length
#define LG_BAD_I2C_RLEN         -56 // bad I2C read length
#define LG_BAD_I2C_CMD          -57 // bad I2C command
#define LG_FILE_OPEN_FAILED     -58 // file open failed
#define LG_BAD_FILE_MODE        -59 // bad file mode
#define LG_BAD_FILE_FLAG        -60 // bad file flag
#define LG_BAD_FILE_READ        -61 // bad file read
#define LG_BAD_FILE_WRITE       -62 // bad file write
#define LG_FILE_NOT_ROPEN       -63 // file not open for read
#define LG_FILE_NOT_WOPEN       -64 // file not open for write
#define LG_BAD_FILE_SEEK        -65 // bad file seek
#define LG_NO_FILE_MATCH        -66 // no files match pattern
#define LG_NO_FILE_ACCESS       -67 // no permission to access file
#define LG_FILE_IS_A_DIR        -68 // file is a directory
#define LG_BAD_SHELL_STATUS     -69 // bad shell return status
#define LG_BAD_SCRIPT_NAME      -70 // bad script name
#define LG_CMD_INTERRUPTED      -71 // Python socket command interrupted
#define LG_BAD_EVENT_REQUEST    -72 // bad event request
#define LG_BAD_GPIO_NUMBER      -73 // bad GPIO number
#define LG_BAD_GROUP_SIZE       -74 // bad group size
#define LG_BAD_LINEINFO_IOCTL   -75 // bad lineinfo IOCTL
#define LG_BAD_READ             -76 // bad GPIO read
#define LG_BAD_WRITE            -77 // bad GPIO write
#define LG_CANNOT_OPEN_CHIP     -78 // can not open gpiochip
#define LG_GPIO_BUSY            -79 // GPIO busy
#define LG_GPIO_NOT_ALLOCATED   -80 // GPIO not allocated
#define LG_NOT_A_GPIOCHIP       -81 // not a gpiochip
#define LG_NOT_ENOUGH_MEMORY    -82 // not enough memory
#define LG_POLL_FAILED          -83 // GPIO poll failed
#define LG_TOO_MANY_GPIOS       -84 // too many GPIO
#define LG_UNEGPECTED_ERROR     -85 // unexpected error
#define LG_BAD_PWM_MICROS       -86 // bad PWM micros
#define LG_NOT_GROUP_LEADER     -87 // GPIO not the group leader
#define LG_SPI_IOCTL_FAILED     -88 // SPI iOCTL failed
#define LG_BAD_GPIOCHIP         -89 // bad gpiochip
#define LG_BAD_CHIPINFO_IOCTL   -90 // bad chipinfo IOCTL
#define LG_BAD_CONFIG_FILE      -91 // bad configuration file
#define LG_BAD_CONFIG_VALUE     -92 // bad configuration value
#define LG_NO_PERMISSIONS       -93 // no permission to perform action
#define LG_BAD_USERNAME         -94 // bad user name
#define LG_BAD_SECRET           -95 // bad secret for user
#define LG_TX_QUEUE_FULL        -96 // TX queue full
#define LG_BAD_CONFIG_ID        -97 // bad configuration id
#define LG_BAD_DEBOUNCE_MICS    -98 // bad debounce microseconds
#define LG_BAD_WATCHDOG_MICS    -99 // bad watchdog microseconds
#define LG_BAD_SERVO_FREQ      -100 // bad servo frequency
#define LG_BAD_SERVO_WIDTH     -101 // bad servo pulsewidth
#define LG_BAD_PWM_FREQ        -102 // bad PWM frequency
#define LG_BAD_PWM_DUTY        -103 // bad PWM dutycycle
#define LG_GPIO_NOT_AN_OUTPUT  -104 // GPIO not set as an output
#define LG_INVALID_GROUP_ALERT -105 // can not set a group to alert

/*DEF_E*/


#endif