1 /* 2 * GPIO Testing Device Driver 3 * 4 * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com> 5 * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamvor.zhangjian@linaro.org> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the 9 * Free Software Foundation; either version 2 of the License, or (at your 10 * option) any later version. 11 * 12 */ 13 14 #include <linux/init.h> 15 #include <linux/module.h> 16 #include <linux/gpio/driver.h> 17 #include <linux/platform_device.h> 18 19 #define GPIO_NAME "gpio-mockup" 20 #define MAX_GC 10 21 22 enum direction { 23 OUT, 24 IN 25 }; 26 27 /* 28 * struct gpio_pin_status - structure describing a GPIO status 29 * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out 30 * @value: Configures status of the gpio as 0(low) or 1(high) 31 */ 32 struct gpio_pin_status { 33 enum direction dir; 34 bool value; 35 }; 36 37 struct mockup_gpio_controller { 38 struct gpio_chip gc; 39 struct gpio_pin_status *stats; 40 }; 41 42 static int gpio_mockup_ranges[MAX_GC << 1]; 43 static int gpio_mockup_params_nr; 44 module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400); 45 46 const char pins_name_start = 'A'; 47 48 static int mockup_gpio_get(struct gpio_chip *gc, unsigned int offset) 49 { 50 struct mockup_gpio_controller *cntr = gpiochip_get_data(gc); 51 52 return cntr->stats[offset].value; 53 } 54 55 static void mockup_gpio_set(struct gpio_chip *gc, unsigned int offset, 56 int value) 57 { 58 struct mockup_gpio_controller *cntr = gpiochip_get_data(gc); 59 60 cntr->stats[offset].value = !!value; 61 } 62 63 static int mockup_gpio_dirout(struct gpio_chip *gc, unsigned int offset, 64 int value) 65 { 66 struct mockup_gpio_controller *cntr = gpiochip_get_data(gc); 67 68 mockup_gpio_set(gc, offset, value); 69 cntr->stats[offset].dir = OUT; 70 return 0; 71 } 72 73 static int mockup_gpio_dirin(struct gpio_chip *gc, unsigned int offset) 74 { 75 struct mockup_gpio_controller *cntr = gpiochip_get_data(gc); 76 77 cntr->stats[offset].dir = IN; 78 return 0; 79 } 80 81 static int mockup_gpio_get_direction(struct gpio_chip *gc, unsigned int offset) 82 { 83 struct mockup_gpio_controller *cntr = gpiochip_get_data(gc); 84 85 return cntr->stats[offset].dir; 86 } 87 88 static int mockup_gpio_add(struct device *dev, 89 struct mockup_gpio_controller *cntr, 90 const char *name, int base, int ngpio) 91 { 92 int ret; 93 94 cntr->gc.base = base; 95 cntr->gc.ngpio = ngpio; 96 cntr->gc.label = name; 97 cntr->gc.owner = THIS_MODULE; 98 cntr->gc.parent = dev; 99 cntr->gc.get = mockup_gpio_get; 100 cntr->gc.set = mockup_gpio_set; 101 cntr->gc.direction_output = mockup_gpio_dirout; 102 cntr->gc.direction_input = mockup_gpio_dirin; 103 cntr->gc.get_direction = mockup_gpio_get_direction; 104 cntr->stats = devm_kzalloc(dev, sizeof(*cntr->stats) * cntr->gc.ngpio, 105 GFP_KERNEL); 106 if (!cntr->stats) { 107 ret = -ENOMEM; 108 goto err; 109 } 110 ret = devm_gpiochip_add_data(dev, &cntr->gc, cntr); 111 if (ret) 112 goto err; 113 114 dev_info(dev, "gpio<%d..%d> add successful!", base, base + ngpio); 115 return 0; 116 err: 117 dev_err(dev, "gpio<%d..%d> add failed!", base, base + ngpio); 118 return ret; 119 } 120 121 static int mockup_gpio_probe(struct platform_device *pdev) 122 { 123 struct device *dev = &pdev->dev; 124 struct mockup_gpio_controller *cntr; 125 int ret; 126 int i; 127 int base; 128 int ngpio; 129 char chip_name[sizeof(GPIO_NAME) + 3]; 130 131 if (gpio_mockup_params_nr < 2) 132 return -EINVAL; 133 134 cntr = devm_kzalloc(dev, sizeof(*cntr) * (gpio_mockup_params_nr >> 1), 135 GFP_KERNEL); 136 if (!cntr) 137 return -ENOMEM; 138 139 platform_set_drvdata(pdev, cntr); 140 141 for (i = 0; i < gpio_mockup_params_nr >> 1; i++) { 142 base = gpio_mockup_ranges[i * 2]; 143 if (base == -1) 144 ngpio = gpio_mockup_ranges[i * 2 + 1]; 145 else 146 ngpio = gpio_mockup_ranges[i * 2 + 1] - base; 147 148 if (ngpio >= 0) { 149 sprintf(chip_name, "%s-%c", GPIO_NAME, 150 pins_name_start + i); 151 ret = mockup_gpio_add(dev, &cntr[i], 152 chip_name, base, ngpio); 153 } else { 154 ret = -1; 155 } 156 if (ret) { 157 if (base < 0) 158 dev_err(dev, "gpio<%d..%d> add failed\n", 159 base, ngpio); 160 else 161 dev_err(dev, "gpio<%d..%d> add failed\n", 162 base, base + ngpio); 163 164 return ret; 165 } 166 } 167 168 return 0; 169 } 170 171 static struct platform_driver mockup_gpio_driver = { 172 .driver = { 173 .name = GPIO_NAME, 174 }, 175 .probe = mockup_gpio_probe, 176 }; 177 178 static struct platform_device *pdev; 179 static int __init mock_device_init(void) 180 { 181 int err; 182 183 pdev = platform_device_alloc(GPIO_NAME, -1); 184 if (!pdev) 185 return -ENOMEM; 186 187 err = platform_device_add(pdev); 188 if (err) { 189 platform_device_put(pdev); 190 return err; 191 } 192 193 err = platform_driver_register(&mockup_gpio_driver); 194 if (err) { 195 platform_device_unregister(pdev); 196 return err; 197 } 198 199 return 0; 200 } 201 202 static void __exit mock_device_exit(void) 203 { 204 platform_driver_unregister(&mockup_gpio_driver); 205 platform_device_unregister(pdev); 206 } 207 208 module_init(mock_device_init); 209 module_exit(mock_device_exit); 210 211 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>"); 212 MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>"); 213 MODULE_DESCRIPTION("GPIO Testing driver"); 214 MODULE_LICENSE("GPL v2"); 215