1 /* 2 * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 7 * Redistributions of source code must retain the above copyright notice, this 8 * list of conditions and the following disclaimer. 9 * 10 * Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 14 * Neither the name of ARM nor the names of its contributors may be used 15 * to endorse or promote products derived from this software without specific 16 * prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 * 30 * GPIO -- General Purpose Input/Output 31 * 32 * Defines a simple and generic interface to access GPIO device. 33 * 34 */ 35 36 #include <assert.h> 37 #include <errno.h> 38 #include <gpio.h> 39 40 /* 41 * The gpio implementation 42 */ 43 static const gpio_ops_t *ops; 44 45 int gpio_get_direction(int gpio) 46 { 47 assert(ops); 48 assert(ops->get_direction != 0); 49 assert(gpio >= 0); 50 51 return ops->get_direction(gpio); 52 } 53 54 void gpio_set_direction(int gpio, int direction) 55 { 56 assert(ops); 57 assert(ops->set_direction != 0); 58 assert((direction == GPIO_DIR_OUT) || (direction == GPIO_DIR_IN)); 59 assert(gpio >= 0); 60 61 ops->set_direction(gpio, direction); 62 } 63 64 int gpio_get_value(int gpio) 65 { 66 assert(ops); 67 assert(ops->get_value != 0); 68 assert(gpio >= 0); 69 70 return ops->get_value(gpio); 71 } 72 73 void gpio_set_value(int gpio, int value) 74 { 75 assert(ops); 76 assert(ops->set_value != 0); 77 assert((value == GPIO_LEVEL_LOW) || (value == GPIO_LEVEL_HIGH)); 78 assert(gpio >= 0); 79 80 ops->set_value(gpio, value); 81 } 82 83 void gpio_set_pull(int gpio, int pull) 84 { 85 assert(ops); 86 assert(ops->set_pull != 0); 87 assert((pull == GPIO_PULL_NONE) || (pull == GPIO_PULL_UP) || 88 (pull == GPIO_PULL_DOWN)); 89 assert(gpio >= 0); 90 91 ops->set_pull(gpio, pull); 92 } 93 94 int gpio_get_pull(int gpio) 95 { 96 assert(ops); 97 assert(ops->get_pull != 0); 98 assert(gpio >= 0); 99 100 return ops->get_pull(gpio); 101 } 102 103 /* 104 * Initialize the gpio. The fields in the provided gpio 105 * ops pointer must be valid. 106 */ 107 void gpio_init(const gpio_ops_t *ops_ptr) 108 { 109 assert(ops_ptr != 0 && 110 (ops_ptr->get_direction != 0) && 111 (ops_ptr->set_direction != 0) && 112 (ops_ptr->get_value != 0) && 113 (ops_ptr->set_value != 0)); 114 115 ops = ops_ptr; 116 } 117