led: Add on board LED support

This patch adds support for using on board LED through sysfs.
Commonly available LED parameters are supported.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa.h

@@ -34,6 +34,7 @@ extern "C" {
 #include "mraa/i2c.h"
 #include "mraa/uart.h"
 #include "mraa/uart_ow.h"
+#include "mraa/led.h"
 
 #ifdef __cplusplus
 }

api/mraa.hpp

@@ -31,3 +31,4 @@
 #include "mraa/i2c.hpp"
 #include "mraa/spi.hpp"
 #include "mraa/uart.hpp"
+#include "mraa/led.hpp"

api/mraa/led.h

@@ -0,0 +1,111 @@
+/*
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ * Copyright (c) 2017 Linaro Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * 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 OR COPYRIGHT HOLDERS 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.
+ */
+
+#pragma once
+
+/**
+ * @file
+ * @brief LED module
+ *
+ * LED is the Light Emitting Diode interface to libmraa. It is used to
+ * access the on board LED's via sysfs.
+ *
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "common.h"
+#include <stdio.h>
+
+/**
+ * Opaque pointer definition to the internal struct _led
+ */
+typedef struct _led* mraa_led_context;
+
+/**
+ * Initialise led_context, based on led function name.
+ * The structure of LED entry in sysfs is "devicename:colour:function"
+ * This api expects only one unique LED identifier which would be
+ * "function" name most often. For instance, `mraa_led_init("user4");`
+ *
+ *  @param led Name of the LED
+ *  @returns LED context or NULL
+ */
+mraa_led_context mraa_led_init(const char* led);
+
+/**
+ * Set LED brightness
+ *
+ *  @param dev LED context
+ *  @param value Integer value to write
+ *  @returns Result of operation
+ */
+mraa_result_t mraa_led_set_brightness(mraa_led_context dev, int value);
+
+/**
+ * Read LED brightness
+ *
+ *  @param dev LED context
+ *  @returns Brightness value
+ */
+int mraa_led_read_brightness(mraa_led_context dev);
+
+/**
+ * Read LED maximum brightness
+ *
+ *  @param dev LED context
+ *  @returns Maximum brightness value
+ */
+int mraa_led_read_max_brightness(mraa_led_context dev);
+
+/**
+ * Set LED trigger
+ *
+ *  @param dev LED context
+ *  @param trigger Type of trigger to set
+ *  @returns Result of operation
+ */
+mraa_result_t mraa_led_set_trigger(mraa_led_context dev, const char* trigger);
+
+/**
+ * Clear active LED trigger
+ *
+ *  @param dev LED context
+ *  @returns Result of operation
+ */
+mraa_result_t mraa_led_clear_trigger(mraa_led_context dev);
+
+/**
+ * Close LED file descriptors and free the context memory
+ *
+ *  @param dev LED context
+ *  @returns Result of operation
+ */
+mraa_result_t mraa_led_close(mraa_led_context dev);
+
+#ifdef __cplusplus
+}
+#endif

api/mraa/led.hpp

@@ -0,0 +1,139 @@
+/*
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ * Copyright (c) 2017 Linaro Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * 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 OR COPYRIGHT HOLDERS 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.
+ */
+
+#pragma once
+
+#include "led.h"
+#include "types.hpp"
+#include <stdexcept>
+
+namespace mraa
+{
+
+/**
+ * @brief API to Light Emitting Diode
+ *
+ * This file defines the LED interface for libmraa
+ *
+ */
+class Led
+{
+  public:
+    /**
+     * Instantiates an LED object
+     *
+     * @param led LED fuction name to use
+     */
+    Led(const char* led)
+    {
+        m_led = mraa_led_init(led);
+
+        if (m_led == NULL) {
+            throw std::invalid_argument("Invalid LED name specified");
+        }
+    }
+
+    /**
+     * LED Constructor, takes a pointer to a LED context and initialises
+     * the LED class
+     *
+     * @param led_context void * to LED context
+     */
+    Led(void* led_context)
+    {
+        m_led = (mraa_led_context) led_context;
+        if (m_led == NULL) {
+            throw std::invalid_argument("Invalid LED name specified");
+        }
+    }
+
+    /**
+     * LED object destructor
+     */
+    ~Led()
+    {
+        mraa_led_close(m_led);
+    }
+
+    /**
+     * Set LED brightness value
+     *
+     * @param value Value to set LED brightness
+     * @return Result of operation
+     */
+    Result
+    setBrightness(int value)
+    {
+        return (Result) mraa_led_set_brightness(m_led, value);
+    }
+
+    /**
+     * Read LED brightness value
+     *
+     * @return LED brightness value
+     */
+    int
+    readBrightness()
+    {
+        return mraa_led_read_brightness(m_led);
+    }
+
+    /**
+     * Read LED maximum brightness value
+     *
+     * @return LED max brightness value
+     */
+    int
+    readMaxBrightness()
+    {
+        return mraa_led_read_max_brightness(m_led);
+    }
+
+    /**
+     * Set LED trigger
+     *
+     * @param trigger Type of trigger to set
+     * @return Result of operation
+     */
+    Result
+    trigger(const char* trigger)
+    {
+        return (Result) mraa_led_set_trigger(m_led, trigger);
+    }
+
+    /**
+     * Clear active LED trigger
+     *
+     * @return Result of operation
+     */
+    Result
+    clearTrigger()
+    {
+        return (Result) mraa_led_clear_trigger(m_led);
+    }
+
+  private:
+    mraa_led_context m_led;
+};
+}

include/mraa_internal_types.h

@@ -241,6 +241,20 @@ struct _iio {
 };
 #endif
 
+/**
+ * A structure representing an LED device
+ */
+struct _led {
+    /*@{*/
+    int count; /**< total LED count in a platform */
+    char *led_name; /**< LED name */
+    char led_path[64]; /**< sysfs path of the LED */
+    int trig_fd; /**< trigger file descriptor */
+    int bright_fd; /**< brightness file descriptor */
+    int max_bright_fd; /**< maximum brightness file descriptor */
+    /*@}*/
+};
+
 /**
  * A bitfield representing the capabilities of a pin.
  */

src/CMakeLists.txt

@@ -28,6 +28,7 @@ set (mraa_LIB_SRCS_NOAUTO
   ${PROJECT_SOURCE_DIR}/src/spi/spi.c
   ${PROJECT_SOURCE_DIR}/src/aio/aio.c
   ${PROJECT_SOURCE_DIR}/src/uart/uart.c
+  ${PROJECT_SOURCE_DIR}/src/led/led.c
   ${mraa_LIB_SRCS_NOAUTO}
 )
 
@@ -236,7 +237,7 @@ mraa_create_install_pkgconfig (mraa.pc ${LIB_INSTALL_DIR}/pkgconfig)
 
 if (DOXYGEN_FOUND)
   set (CMAKE_SWIG_FLAGS -DDOXYGEN=${DOXYGEN_FOUND})
-  set (DOCCLASSES aio gpio i2c pwm spi uart)
+  set (DOCCLASSES aio gpio i2c pwm spi uart led)
   # CPP class headers
   foreach (_file ${DOCCLASSES})
     add_custom_command (OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${_file}_class_doc.i

src/led/led.c

@@ -0,0 +1,380 @@
+/*
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ * Copyright (c) 2017 Linaro Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * 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 OR COPYRIGHT HOLDERS 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.
+ */
+
+#include "led.h"
+#include "mraa_internal.h"
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/errno.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define SYSFS_CLASS_LED "/sys/class/leds"
+#define MAX_SIZE 64
+
+static mraa_result_t
+mraa_led_get_trigfd(mraa_led_context dev)
+{
+    char buf[MAX_SIZE];
+
+    snprintf(buf, MAX_SIZE, "%s/%s", dev->led_path, "trigger");
+    dev->trig_fd = open(buf, O_RDWR);
+    if (dev->trig_fd == -1) {
+        syslog(LOG_ERR, "led: trigger: Failed to open 'trigger': %s", strerror(errno));
+        return MRAA_ERROR_INVALID_RESOURCE;
+    }
+
+    return MRAA_SUCCESS;
+}
+
+static mraa_result_t
+mraa_led_get_brightfd(mraa_led_context dev)
+{
+    char buf[MAX_SIZE];
+
+    snprintf(buf, MAX_SIZE, "%s/%s", dev->led_path, "brightness");
+    dev->bright_fd = open(buf, O_RDWR);
+    if (dev->bright_fd == -1) {
+        syslog(LOG_ERR, "led: brightness: Failed to open 'brightness': %s", strerror(errno));
+        return MRAA_ERROR_INVALID_RESOURCE;
+    }
+
+    return MRAA_SUCCESS;
+}
+
+static mraa_result_t
+mraa_led_get_maxbrightfd(mraa_led_context dev)
+{
+    char buf[MAX_SIZE];
+
+    snprintf(buf, MAX_SIZE, "%s/%s", dev->led_path, "max_brightness");
+    dev->max_bright_fd = open(buf, O_RDONLY);
+    if (dev->max_bright_fd == -1) {
+        syslog(LOG_ERR, "led: max_brightness: Failed to open 'max_brightness': %s", strerror(errno));
+        return MRAA_ERROR_INVALID_RESOURCE;
+    }
+
+    return MRAA_SUCCESS;
+}
+
+static mraa_led_context
+mraa_led_init_internal(const char* led)
+{
+    DIR* dir;
+    struct dirent* entry;
+    int cnt = 0;
+
+    mraa_led_context dev = (mraa_led_context) calloc(1, sizeof(struct _led));
+    if (dev == NULL) {
+        syslog(LOG_CRIT, "led: init: Failed to allocate memory for context");
+        return NULL;
+    }
+
+    dev->led_name = NULL;
+    dev->trig_fd = -1;
+    dev->bright_fd = -1;
+    dev->max_bright_fd = -1;
+
+    if ((dir = opendir(SYSFS_CLASS_LED)) != NULL) {
+        /* get the led name from sysfs path */
+        while ((entry = readdir(dir)) != NULL) {
+            if (strstr((const char*) entry->d_name, led)) {
+                dev->led_name = (char*) entry->d_name;
+            }
+            cnt++;
+        }
+    }
+    dev->count = cnt;
+    if (dev->led_name == NULL) {
+        syslog(LOG_CRIT, "led: init: unknown device specified");
+        closedir(dir);
+        free(dev);
+        return NULL;
+    }
+
+    closedir(dir);
+    return dev;
+}
+
+mraa_led_context
+mraa_led_init(const char* led)
+{
+    mraa_led_context dev = NULL;
+    char directory[MAX_SIZE];
+    struct stat dir;
+
+    if (plat == NULL) {
+        syslog(LOG_ERR, "led: init: platform not initialised");
+        return NULL;
+    }
+
+    if (led == NULL) {
+        syslog(LOG_ERR, "led: init: invalid device specified");
+        return NULL;
+    }
+
+    dev = mraa_led_init_internal(led);
+    if (dev == NULL) {
+        return NULL;
+    }
+
+    snprintf(directory, MAX_SIZE, "%s/%s", SYSFS_CLASS_LED, dev->led_name);
+    if (stat(directory, &dir) == 0 && S_ISDIR(dir.st_mode)) {
+        syslog(LOG_NOTICE, "led: init: current user don't have access rights for using LED %s", dev->led_name);
+    }
+    strncpy(dev->led_path, (const char*) directory, sizeof(directory));
+
+    return dev;
+}
+
+mraa_result_t
+mraa_led_set_brightness(mraa_led_context dev, int value)
+{
+    char buf[MAX_SIZE];
+    int length;
+
+    if (dev == NULL) {
+        syslog(LOG_ERR, "led: set_brightness: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
+    if (dev->trig_fd != -1) {
+        close(dev->trig_fd);
+        dev->trig_fd = -1;
+    }
+
+    if (dev->max_bright_fd != -1) {
+        close(dev->max_bright_fd);
+        dev->max_bright_fd = -1;
+    }
+
+    if (dev->bright_fd == -1) {
+        if (mraa_led_get_brightfd(dev) != MRAA_SUCCESS) {
+            return MRAA_ERROR_INVALID_RESOURCE;
+        }
+    }
+
+    if (lseek(dev->bright_fd, 0, SEEK_SET) == -1) {
+        syslog(LOG_ERR, "led: set_brightness: Failed to lseek 'brightness': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+
+    length = snprintf(buf, sizeof(buf), "%d", value);
+    if (write(dev->bright_fd, buf, length * sizeof(char)) == -1) {
+        syslog(LOG_ERR, "led: set_brightness: Failed to write 'brightness': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+
+    return MRAA_SUCCESS;
+}
+
+int
+mraa_led_read_brightness(mraa_led_context dev)
+{
+    char buf[3];
+
+    if (dev == NULL) {
+        syslog(LOG_ERR, "led: read_brightness: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
+    if (dev->trig_fd != -1) {
+        close(dev->trig_fd);
+        dev->trig_fd = -1;
+    }
+
+    if (dev->max_bright_fd != -1) {
+        close(dev->max_bright_fd);
+        dev->max_bright_fd = -1;
+    }
+
+    if (dev->bright_fd == -1) {
+        if (mraa_led_get_brightfd(dev) != MRAA_SUCCESS) {
+            return MRAA_ERROR_INVALID_RESOURCE;
+        }
+    } else {
+        lseek(dev->bright_fd, 0, SEEK_SET);
+    }
+
+    if (read(dev->bright_fd, buf, 3 * sizeof(char)) == -1) {
+        syslog(LOG_ERR, "led: read_brightness: Failed to read 'brightness': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+    lseek(dev->bright_fd, 0, SEEK_SET);
+
+    return (int) atoi(buf);
+}
+
+int
+mraa_led_read_max_brightness(mraa_led_context dev)
+{
+    char buf[3];
+
+    if (dev == NULL) {
+        syslog(LOG_ERR, "led: read_max_brightness: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
+    if (dev->trig_fd != -1) {
+        close(dev->trig_fd);
+        dev->trig_fd = -1;
+    }
+
+    if (dev->bright_fd != -1) {
+        close(dev->bright_fd);
+        dev->bright_fd = -1;
+    }
+
+    if (dev->max_bright_fd == -1) {
+        if (mraa_led_get_maxbrightfd(dev) != MRAA_SUCCESS) {
+            return MRAA_ERROR_INVALID_RESOURCE;
+        }
+    } else {
+        lseek(dev->max_bright_fd, 0, SEEK_SET);
+    }
+
+    if (read(dev->max_bright_fd, buf, 3 * sizeof(char)) == -1) {
+        syslog(LOG_ERR, "led: read_max_brightness: Failed to read 'max_brightness': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+    lseek(dev->max_bright_fd, 0, SEEK_SET);
+
+    return (int) atoi(buf);
+}
+
+mraa_result_t
+mraa_led_set_trigger(mraa_led_context dev, const char* trigger)
+{
+    char buf[MAX_SIZE];
+    int length;
+
+    if (dev == NULL) {
+        syslog(LOG_ERR, "led: set_trigger: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
+    if (dev->bright_fd != -1) {
+        close(dev->bright_fd);
+        dev->bright_fd = -1;
+    }
+
+    if (dev->max_bright_fd != -1) {
+        close(dev->max_bright_fd);
+        dev->max_bright_fd = -1;
+    }
+
+    if (trigger == NULL) {
+        syslog(LOG_ERR, "led: trigger: invalid trigger specified");
+        return MRAA_ERROR_INVALID_RESOURCE;
+    }
+
+    if (dev->trig_fd == -1) {
+        if (mraa_led_get_trigfd(dev) != MRAA_SUCCESS) {
+            return MRAA_ERROR_INVALID_RESOURCE;
+        }
+    }
+
+    if (lseek(dev->trig_fd, 0, SEEK_SET) == -1) {
+        syslog(LOG_ERR, "led: set_trigger: Failed to lseek 'trigger': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+
+    length = snprintf(buf, sizeof(buf), "%s", trigger);
+    if (write(dev->trig_fd, buf, length * sizeof(char)) == -1) {
+        syslog(LOG_ERR, "led: set_trigger: Failed to write 'trigger': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+
+    return MRAA_SUCCESS;
+}
+
+mraa_result_t
+mraa_led_clear_trigger(mraa_led_context dev)
+{
+    char buf[1] = { '0' };
+
+    if (dev == NULL) {
+        syslog(LOG_ERR, "led: clear_trigger: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
+    if (dev->trig_fd != -1) {
+        close(dev->trig_fd);
+        dev->trig_fd = -1;
+    }
+
+    if (dev->max_bright_fd != -1) {
+        close(dev->max_bright_fd);
+        dev->max_bright_fd = -1;
+    }
+
+    if (dev->bright_fd == -1) {
+        if (mraa_led_get_brightfd(dev) != MRAA_SUCCESS) {
+            return MRAA_ERROR_INVALID_RESOURCE;
+        }
+    }
+
+    if (lseek(dev->bright_fd, 0, SEEK_SET) == -1) {
+        syslog(LOG_ERR, "led: clear_trigger: Failed to lseek 'brightness': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+
+    /* writing 0 to brightness clears trigger */
+    if (write(dev->bright_fd, buf, 1) == -1) {
+        syslog(LOG_ERR, "led: clear_trigger: Failed to write 'brightness': %s", strerror(errno));
+        return MRAA_ERROR_UNSPECIFIED;
+    }
+
+    return MRAA_SUCCESS;
+}
+
+mraa_result_t
+mraa_led_close(mraa_led_context dev)
+{
+    if (dev == NULL) {
+        syslog(LOG_ERR, "led: close: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
+    if (dev->bright_fd != -1) {
+        close(dev->bright_fd);
+    }
+
+    if (dev->trig_fd != -1) {
+        close(dev->trig_fd);
+    }
+
+    if (dev->max_bright_fd != -1) {
+        close(dev->max_bright_fd);
+    }
+
+    free(dev);
+
+    return MRAA_SUCCESS;
+}

src/mraa.i

@@ -13,6 +13,7 @@
     #include "spi.hpp"
     #include "aio.hpp"
     #include "uart.hpp"
+    #include "led.hpp"
 %}
 
 %exception {
@@ -34,6 +35,7 @@
 %template (spiFromDesc) mraa::initIo<mraa::Spi>;
 %template (i2cFromDesc) mraa::initIo<mraa::I2c>;
 %template (pwmFromDesc) mraa::initIo<mraa::Pwm>;
+%template (ledFromDesc) mraa::initIo<mraa::Led>;
 
 %ignore Aio(void* aio_context);
 %ignore Pwm(void* pwm_context);
@@ -41,6 +43,7 @@
 %ignore Spi(void* spi_context);
 %ignore I2c(void* i2c_context);
 %ignore Gpio(void* gpio_context);
+%ignore Led(void* led_context);
 
 %ignore Gpio::nop(uv_work_t* req);
 %ignore Gpio::v8isr(uv_work_t* req);
@@ -59,3 +62,5 @@
 %include "aio.hpp"
 
 %include "uart.hpp"
+
+%include "led.hpp"