/* * Author: Manivannan Sadhasivam * Copyright (c) 2018, 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. * * Example usage: Reads maximum brightness value for user led and turns it * on/off depending on current state. Then sets led trigger * to heartbeat. * */ /* standard headers */ #include #include #include /* mraa header */ #include "mraa/led.h" /* LED name */ #define USER_LED "user1" /* trigger type */ #define LED_TRIGGER "heartbeat" int main(void) { mraa_result_t status = MRAA_SUCCESS; mraa_led_context led; int val; /* initialize mraa for the platform (not needed most of the time) */ mraa_init(); //! [Interesting] /* initialize LED */ led = mraa_led_init(USER_LED); if (led == NULL) { fprintf(stderr, "Failed to initialize LED\n"); mraa_deinit(); return EXIT_FAILURE; } /* read maximum brightness */ val = mraa_led_read_max_brightness(led); fprintf(stdout, "maximum brightness value for LED is: %d\n", val); if (val >= 1) { val = 0; } else { /* never reached mostly */ val = 1; } /* turn LED on/off depending on max_brightness value */ status = mraa_led_set_brightness(led, val); if (status != MRAA_SUCCESS) { fprintf(stderr, "unable to set LED brightness\n"); goto err_exit; } /* sleep for 5 seconds */ sleep(5); /* set LED trigger to heartbeat */ status = mraa_led_set_trigger(led, LED_TRIGGER); if (status != MRAA_SUCCESS) { fprintf(stderr, "unable to set LED trigger to: heartbeat\n"); goto err_exit; } fprintf(stdout, "LED trigger set to: heartbeat\n"); /* close LED */ mraa_led_close(led); //! [Interesting] /* deinitialize mraa for the platform (not needed most of the times) */ mraa_deinit(); return EXIT_SUCCESS; err_exit: mraa_result_print(status); /* deinitialize mraa for the platform (not needed most of the times) */ mraa_deinit(); return EXIT_FAILURE; }