Add a TSL2561 driver and example usage

examples/tsl2561/Makefile

@@ -0,0 +1,3 @@
+PROGRAM=tsl2561_example
+EXTRA_COMPONENTS = extras/i2c extras/tsl2561
+include ../../common.mk

examples/tsl2561/tsl2561_example.c

@@ -0,0 +1,69 @@
+/*
+ * This sample code is in the public domain.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "esp/uart.h"
+#include "FreeRTOS.h"
+#include "i2c/i2c.h"
+#include "task.h"
+#include "tsl2561/tsl2561.h"
+
+/* An example using the TSL2561 light sensor
+ * to read and print lux values from a sensor
+ * attached to GPIO pin 2 (SCL) and GPIO pin 0 (SDA)
+ * Connect 3.3v from the ESP to Vin and GND to GND
+ */
+
+#define SCL_PIN (2)
+#define SDA_PIN (0)
+
+void tsl2561MeasurementTask(void *pvParameters)
+{
+    tsl2561_t lightSensor;
+
+    // Options:
+    // TSL2561_I2C_ADDR_VCC   (0x49)
+    // TSL2561_I2C_ADDR_GND   (0x29)
+    // TSL2561_I2C_ADDR_FLOAT (0x39) Default
+    lightSensor.i2c_addr = TSL2561_I2C_ADDR_FLOAT;
+
+    tsl2561_init(&lightSensor);
+
+    // Options:
+    // TSL2561_INTEGRATION_13MS  (0x00)
+    // TSL2561_INTEGRATION_101MS (0x01)
+    // TSL2561_INTEGRATION_402MS (0x02) Default
+    tsl2561_set_integration_time(&lightSensor, TSL2561_INTEGRATION_402MS);
+
+    // Options:
+    // TSL2561_GAIN_1X  (0x00) Default
+    // TSL2561_GAIN_16X (0x10)
+    tsl2561_set_gain(&lightSensor, TSL2561_GAIN_1X);
+
+    uint32_t lux = 0;
+
+    while (1)
+    {
+        if (tsl2561_read_lux(&lightSensor, &lux))
+        {
+            printf("Lux: %u\n", lux);
+        }
+        else
+        {
+            printf("Could not read data from TSL2561\n");
+        }
+
+        // 0.1 second delay
+        vTaskDelay(100 / portTICK_RATE_MS);
+    }
+}
+
+void user_init(void)
+{
+    uart_set_baud(0, 115200);
+    i2c_init(SCL_PIN, SDA_PIN);
+
+    xTaskCreate(tsl2561MeasurementTask, (signed char *)"tsl2561MeasurementTask", 256, NULL, 2, NULL);
+}