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mpu6050 read data by time with kthread wariant #46

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mpu6050 read data by time with kthread wariant #46

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105 changes: 93 additions & 12 deletions mpu6050/mpu6050.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,13 @@
#include <linux/i2c.h>
#include <linux/i2c-dev.h>

#include <linux/time.h>
#include <linux/time64.h>
#include <linux/timekeeping.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/kthread.h>

#include "mpu6050-regs.h"

enum AXES {
Expand All @@ -21,32 +28,70 @@ enum VALUE_TYPE {
};

#define READ_REG_NUM (AXES_NUM * 2 + 1)
#define READ_DEPTH 10

struct mpu6050_data {
struct i2c_client *drv_client;
int head;
int tail;
union {
struct {
int accel[AXES_NUM];
int temperature;
int gyro [AXES_NUM];
} values;
int raw[READ_REG_NUM];
} data;
} data[READ_DEPTH];
};

static const struct i2c_device_id mpu6050_idtable[] = {
{ "mpu6050", 0 },
{ }
};

static struct mpu6050_data g_mpu6050_data;

static ssize_t show_item(struct class *class, struct class_attribute *attr, char *buf);


static struct mpu6050_data g_mpu6050_data;
struct task_struct *hthr;

MODULE_DEVICE_TABLE(i2c, mpu6050_idtable);

static struct class *attr_class;

static int rate = 1000;
static int is_buf;

module_param( rate, int, S_IRUGO );
module_param( is_buf, int, S_IRUGO );

static inline int get_next_pos (int pos, const int depth)
{
int tmp = pos + 1;
if (tmp >= depth) {
tmp -= depth;
}
return tmp;
}

static void mpu6050_data_flush(void)
{
g_mpu6050_data.head = 0;
g_mpu6050_data.tail = 0;
}

static int mpu6050_read_data(void)
{
u8 values[READ_REG_NUM * sizeof(u16)];
int temp, result, i, *p;
int temp, result, i, head, *p;
struct i2c_client *drv_client = g_mpu6050_data.drv_client;

if (drv_client == 0)
return -ENODEV;



result = i2c_smbus_read_i2c_block_data(drv_client, REG_ACCEL_XOUT_H,
READ_REG_NUM * sizeof(u16), (char*) values);

Expand All @@ -55,9 +100,13 @@ static int mpu6050_read_data(void)
return -EINVAL;
}

for (i = 0, p = g_mpu6050_data.data.raw; i < READ_REG_NUM * sizeof(u16); i += 2, ++p)
head = get_next_pos(g_mpu6050_data.head, READ_DEPTH);

for (i = 0, p = g_mpu6050_data.data[head].raw; i < READ_REG_NUM * sizeof(u16); i += 2, ++p)
*p = (s16) ((u16) values[i] << 8 | (u16)values[i + 1]);

g_mpu6050_data.head = head;

/* Temperature in degrees C =
* (TEMP_OUT Register Value as a signed quantity)/340 + 36.53
*/
Expand All @@ -82,6 +131,28 @@ static int mpu6050_read_data(void)
return 0;
}

static int mpu6050_get_data(int *values, int is_buffered)
{
if (is_buffered) {
int tail = g_mpu6050_data.tail;

if (tail == g_mpu6050_data.head)
return 0;

memcpy(values, g_mpu6050_data.data[tail].raw, sizeof(int) * READ_REG_NUM);
g_mpu6050_data.tail = get_next_pos(tail, READ_DEPTH);
}
else {
memcpy(values, g_mpu6050_data.data[g_mpu6050_data.head].raw, sizeof(int) * READ_REG_NUM);
}
return 1;
}

static void update_values(struct work_struct *unused)
{
mpu6050_read_data();
}

static int mpu6050_probe(struct i2c_client *drv_client,
const struct i2c_device_id *id)
{
Expand Down Expand Up @@ -134,11 +205,6 @@ static int mpu6050_remove(struct i2c_client *drv_client)
return 0;
}

static const struct i2c_device_id mpu6050_idtable[] = {
{ "mpu6050", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mpu6050_idtable);

static struct i2c_driver mpu6050_i2c_driver = {
.driver = {
Expand All @@ -165,19 +231,29 @@ struct class_attribute class_attr_array[READ_REG_NUM] = {
static ssize_t show_item(struct class *class, struct class_attribute *attr, char *buf)
{
int index = attr - class_attr_array;
int data[READ_REG_NUM] = {0};
int value = 0;

mpu6050_read_data();
mpu6050_get_data( data, is_buf);

if (index >=0 && index < READ_REG_NUM) {
value = g_mpu6050_data.data.raw[index];
value = data[index];
}

sprintf(buf, "%d\n", value);
return strlen(buf);
}

static struct class *attr_class;
static int mpu6050_get_data_thread( void* data )
{
pr_info("read data thread started\n");
do {
mpu6050_read_data();
msleep(rate);
} while(!kthread_should_stop());
pr_info("exit from thread\n");
return 0;
}

static int mpu6050_init(void)
{
Expand All @@ -190,6 +266,7 @@ static int mpu6050_init(void)
return ret;
}
pr_info("mpu6050: i2c driver created\n");
mpu6050_data_flush();

/* Create class */
attr_class = class_create(THIS_MODULE, "mpu6050");
Expand All @@ -209,13 +286,17 @@ static int mpu6050_init(void)
}

pr_info("mpu6050: sysfs class attributes created\n");
hthr = kthread_run(mpu6050_get_data_thread, NULL, "mpu6050_thread");
pr_info("mpu6050: read thread %p started\n", hthr);

pr_info("mpu6050: module loaded\n");
return 0;
}

static void mpu6050_exit(void)
{
kthread_stop(hthr);

if (attr_class) {
int i;

Expand Down