Add proximity sensor example

compartments/proximity_sensor_example.cc

@@ -0,0 +1,110 @@
+// Copyright lowRISC Contributors.
+// SPDX-License-Identifier: Apache-2.0
+
+#include <compartment.h>
+#include <ctype.h>
+#include <debug.hh>
+#include <platform-i2c.hh>
+#include <platform-rgbctrl.hh>
+#include <thread.h>
+
+const uint8_t APDS9960_ENABLE = 0x80;
+const uint8_t APDS9960_ID     = 0x92;
+const uint8_t APDS9960_PPC    = 0x8E;
+const uint8_t APDS9960_CR1    = 0x8F;
+const uint8_t APDS9960_PDATA  = 0x9C;
+
+const uint8_t APDS9960_ID_EXP      = 0xAB;
+const uint8_t APDS9960_I2C_ADDRESS = 0x39;
+
+/// Expose debugging features unconditionally for this compartment.
+using Debug = ConditionalDebug<true, "proximity sensor example">;
+
+template<class T>
+using Mmio = volatile T *;
+
+static void setup_proximity_sensor(Mmio<OpenTitanI2c> i2c, const uint8_t addr)
+{
+	uint8_t buf[2];
+
+	buf[0] = APDS9960_ID;
+
+	i2c->write(APDS9960_I2C_ADDRESS, buf, 1, false);
+	bool success = i2c->read(APDS9960_I2C_ADDRESS, buf, 1);
+	Debug::Assert(success, "Failed to read proximity sensor ID");
+
+	Debug::log("Proximity sensor ID: {}", buf[0]);
+
+	Debug::Assert(buf[0] == APDS9960_ID_EXP,
+	              "Proximity sensor ID was not expected value of {}, saw {}",
+	              APDS9960_ID_EXP,
+	              buf[0]);
+
+	// Disable everything
+	buf[0] = APDS9960_ENABLE;
+	buf[1] = 0x0;
+	i2c->write(APDS9960_I2C_ADDRESS, buf, 2, true);
+	// Wait for all engines to go idle
+	thread_millisecond_wait(25);
+
+	// Set PEN (proximity enable) and PON (power on)
+	buf[0] = APDS9960_ENABLE;
+	buf[1] = 0x5;
+	i2c->write(APDS9960_I2C_ADDRESS, buf, 2, true);
+	// Wait for power on
+	thread_millisecond_wait(10);
+
+	// Set proximity gain to 8x
+	buf[0] = APDS9960_CR1;
+	buf[1] = 0x0c;
+	i2c->write(APDS9960_I2C_ADDRESS, buf, 2, true);
+
+	// Set proximity pulse length to 4us and pulse count to 16us
+	// (experimentially determined, other values may work better!)
+	buf[0] = APDS9960_PPC;
+	buf[1] = 0x04;
+	i2c->write(APDS9960_I2C_ADDRESS, buf, 2, true);
+}
+
+static uint8_t read_proximity_sensor(Mmio<OpenTitanI2c> i2c)
+{
+	uint8_t buf[1];
+
+	buf[0] = APDS9960_PDATA;
+	i2c->write(APDS9960_I2C_ADDRESS, buf, 1, false);
+	if (!i2c->read(APDS9960_I2C_ADDRESS, buf, 1))
+	{
+		Debug::log("Failed to read proximity sensor value");
+		return 0;
+	}
+
+	return buf[0];
+}
+
+[[noreturn]] void __cheri_compartment("proximity_sensor_example") run()
+{
+	auto i2cSetup = [](Mmio<OpenTitanI2c> i2c) {
+		i2c->reset_fifos();
+		i2c->set_host_mode();
+		i2c->set_speed(1);
+	};
+
+	auto i2c0 = MMIO_CAPABILITY(OpenTitanI2c, i2c0);
+	i2cSetup(i2c0);
+	uint8_t addr;
+
+	auto rgbled = MMIO_CAPABILITY(SonataRGBLEDCtrl, rgbled);
+
+	setup_proximity_sensor(i2c0, APDS9960_I2C_ADDRESS);
+
+	while (true)
+	{
+		uint8_t prox = read_proximity_sensor(i2c0);
+		Debug::log("Proximity is {}\r", prox);
+		rgbled->set_rgb(((prox) >> 3), 0, 0, 0);
+		rgbled->set_rgb(0, (255 - prox) >> 3, 0, 1);
+		rgbled->update();
+
+		thread_millisecond_wait(100);
+	}
+}

xmake.lua

@@ -46,6 +46,10 @@ compartment("gpiolib")
 compartment("led_walk")
     add_files("compartments/led_walk.cc")
 
+compartment("proximity_sensor_example")
+    add_deps("debug")
+    add_files("compartments/proximity_sensor_example.cc")
+
 -- A simple demo using only devices on the Sonata board
 firmware("sonata_simple_demo")
     add_deps("freestanding", "led_walk_raw", "echo", "lcd_test")
@@ -132,3 +136,19 @@ firmware("sonata_led_demo")
         }, {expand = false})
     end)
     after_link(convert_to_uf2)
+
+firmware("proximity_test")
+    add_deps("freestanding", "proximity_sensor_example")
+    on_load(function(target)
+        target:values_set("board", "$(board)")
+        target:values_set("threads", {
+            {
+                compartment = "proximity_sensor_example",
+                priority = 2,
+                entry_point = "run",
+                stack_size = 0x200,
+                trusted_stack_frames = 1
+            }
+        }, {expand = false})
+    end)
+    after_link(convert_to_uf2)