1 /* 2 * LEDs driver for GPIOs 3 * 4 * Copyright (C) 2007 8D Technologies inc. 5 * Raphael Assenat <raph@8d.com> 6 * Copyright (C) 2008 Freescale Semiconductor, Inc. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 */ 13 #include <linux/kernel.h> 14 #include <linux/init.h> 15 #include <linux/platform_device.h> 16 #include <linux/gpio.h> 17 #include <linux/leds.h> 18 #include <linux/of.h> 19 #include <linux/of_platform.h> 20 #include <linux/of_gpio.h> 21 #include <linux/slab.h> 22 #include <linux/workqueue.h> 23 #include <linux/module.h> 24 #include <linux/err.h> 25 26 struct gpio_led_data { 27 struct led_classdev cdev; 28 unsigned gpio; 29 struct work_struct work; 30 u8 new_level; 31 u8 can_sleep; 32 u8 active_low; 33 u8 blinking; 34 int (*platform_gpio_blink_set)(unsigned gpio, int state, 35 unsigned long *delay_on, unsigned long *delay_off); 36 }; 37 38 static void gpio_led_work(struct work_struct *work) 39 { 40 struct gpio_led_data *led_dat = 41 container_of(work, struct gpio_led_data, work); 42 43 if (led_dat->blinking) { 44 led_dat->platform_gpio_blink_set(led_dat->gpio, 45 led_dat->new_level, 46 NULL, NULL); 47 led_dat->blinking = 0; 48 } else 49 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level); 50 } 51 52 static void gpio_led_set(struct led_classdev *led_cdev, 53 enum led_brightness value) 54 { 55 struct gpio_led_data *led_dat = 56 container_of(led_cdev, struct gpio_led_data, cdev); 57 int level; 58 59 if (value == LED_OFF) 60 level = 0; 61 else 62 level = 1; 63 64 if (led_dat->active_low) 65 level = !level; 66 67 /* Setting GPIOs with I2C/etc requires a task context, and we don't 68 * seem to have a reliable way to know if we're already in one; so 69 * let's just assume the worst. 70 */ 71 if (led_dat->can_sleep) { 72 led_dat->new_level = level; 73 schedule_work(&led_dat->work); 74 } else { 75 if (led_dat->blinking) { 76 led_dat->platform_gpio_blink_set(led_dat->gpio, level, 77 NULL, NULL); 78 led_dat->blinking = 0; 79 } else 80 gpio_set_value(led_dat->gpio, level); 81 } 82 } 83 84 static int gpio_blink_set(struct led_classdev *led_cdev, 85 unsigned long *delay_on, unsigned long *delay_off) 86 { 87 struct gpio_led_data *led_dat = 88 container_of(led_cdev, struct gpio_led_data, cdev); 89 90 led_dat->blinking = 1; 91 return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK, 92 delay_on, delay_off); 93 } 94 95 static int create_gpio_led(const struct gpio_led *template, 96 struct gpio_led_data *led_dat, struct device *parent, 97 int (*blink_set)(unsigned, int, unsigned long *, unsigned long *)) 98 { 99 int ret, state; 100 101 led_dat->gpio = -1; 102 103 /* skip leds that aren't available */ 104 if (!gpio_is_valid(template->gpio)) { 105 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n", 106 template->gpio, template->name); 107 return 0; 108 } 109 110 ret = devm_gpio_request(parent, template->gpio, template->name); 111 if (ret < 0) 112 return ret; 113 114 led_dat->cdev.name = template->name; 115 led_dat->cdev.default_trigger = template->default_trigger; 116 led_dat->gpio = template->gpio; 117 led_dat->can_sleep = gpio_cansleep(template->gpio); 118 led_dat->active_low = template->active_low; 119 led_dat->blinking = 0; 120 if (blink_set) { 121 led_dat->platform_gpio_blink_set = blink_set; 122 led_dat->cdev.blink_set = gpio_blink_set; 123 } 124 led_dat->cdev.brightness_set = gpio_led_set; 125 if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) 126 state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low; 127 else 128 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); 129 led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; 130 if (!template->retain_state_suspended) 131 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; 132 133 ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state); 134 if (ret < 0) 135 return ret; 136 137 INIT_WORK(&led_dat->work, gpio_led_work); 138 139 ret = led_classdev_register(parent, &led_dat->cdev); 140 if (ret < 0) 141 return ret; 142 143 return 0; 144 } 145 146 static void delete_gpio_led(struct gpio_led_data *led) 147 { 148 if (!gpio_is_valid(led->gpio)) 149 return; 150 led_classdev_unregister(&led->cdev); 151 cancel_work_sync(&led->work); 152 } 153 154 struct gpio_leds_priv { 155 int num_leds; 156 struct gpio_led_data leds[]; 157 }; 158 159 static inline int sizeof_gpio_leds_priv(int num_leds) 160 { 161 return sizeof(struct gpio_leds_priv) + 162 (sizeof(struct gpio_led_data) * num_leds); 163 } 164 165 /* Code to create from OpenFirmware platform devices */ 166 #ifdef CONFIG_OF_GPIO 167 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev) 168 { 169 struct device_node *np = pdev->dev.of_node, *child; 170 struct gpio_leds_priv *priv; 171 int count, ret; 172 173 /* count LEDs in this device, so we know how much to allocate */ 174 count = of_get_available_child_count(np); 175 if (!count) 176 return ERR_PTR(-ENODEV); 177 178 for_each_available_child_of_node(np, child) 179 if (of_get_gpio(child, 0) == -EPROBE_DEFER) 180 return ERR_PTR(-EPROBE_DEFER); 181 182 priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count), 183 GFP_KERNEL); 184 if (!priv) 185 return ERR_PTR(-ENOMEM); 186 187 for_each_available_child_of_node(np, child) { 188 struct gpio_led led = {}; 189 enum of_gpio_flags flags; 190 const char *state; 191 192 led.gpio = of_get_gpio_flags(child, 0, &flags); 193 led.active_low = flags & OF_GPIO_ACTIVE_LOW; 194 led.name = of_get_property(child, "label", NULL) ? : child->name; 195 led.default_trigger = 196 of_get_property(child, "linux,default-trigger", NULL); 197 state = of_get_property(child, "default-state", NULL); 198 if (state) { 199 if (!strcmp(state, "keep")) 200 led.default_state = LEDS_GPIO_DEFSTATE_KEEP; 201 else if (!strcmp(state, "on")) 202 led.default_state = LEDS_GPIO_DEFSTATE_ON; 203 else 204 led.default_state = LEDS_GPIO_DEFSTATE_OFF; 205 } 206 207 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++], 208 &pdev->dev, NULL); 209 if (ret < 0) { 210 of_node_put(child); 211 goto err; 212 } 213 } 214 215 return priv; 216 217 err: 218 for (count = priv->num_leds - 2; count >= 0; count--) 219 delete_gpio_led(&priv->leds[count]); 220 return ERR_PTR(-ENODEV); 221 } 222 223 static const struct of_device_id of_gpio_leds_match[] = { 224 { .compatible = "gpio-leds", }, 225 {}, 226 }; 227 #else /* CONFIG_OF_GPIO */ 228 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev) 229 { 230 return ERR_PTR(-ENODEV); 231 } 232 #endif /* CONFIG_OF_GPIO */ 233 234 235 static int gpio_led_probe(struct platform_device *pdev) 236 { 237 struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev); 238 struct gpio_leds_priv *priv; 239 int i, ret = 0; 240 241 242 if (pdata && pdata->num_leds) { 243 priv = devm_kzalloc(&pdev->dev, 244 sizeof_gpio_leds_priv(pdata->num_leds), 245 GFP_KERNEL); 246 if (!priv) 247 return -ENOMEM; 248 249 priv->num_leds = pdata->num_leds; 250 for (i = 0; i < priv->num_leds; i++) { 251 ret = create_gpio_led(&pdata->leds[i], 252 &priv->leds[i], 253 &pdev->dev, pdata->gpio_blink_set); 254 if (ret < 0) { 255 /* On failure: unwind the led creations */ 256 for (i = i - 1; i >= 0; i--) 257 delete_gpio_led(&priv->leds[i]); 258 return ret; 259 } 260 } 261 } else { 262 priv = gpio_leds_create_of(pdev); 263 if (IS_ERR(priv)) 264 return PTR_ERR(priv); 265 } 266 267 platform_set_drvdata(pdev, priv); 268 269 return 0; 270 } 271 272 static int gpio_led_remove(struct platform_device *pdev) 273 { 274 struct gpio_leds_priv *priv = platform_get_drvdata(pdev); 275 int i; 276 277 for (i = 0; i < priv->num_leds; i++) 278 delete_gpio_led(&priv->leds[i]); 279 280 return 0; 281 } 282 283 static struct platform_driver gpio_led_driver = { 284 .probe = gpio_led_probe, 285 .remove = gpio_led_remove, 286 .driver = { 287 .name = "leds-gpio", 288 .owner = THIS_MODULE, 289 .of_match_table = of_match_ptr(of_gpio_leds_match), 290 }, 291 }; 292 293 module_platform_driver(gpio_led_driver); 294 295 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>"); 296 MODULE_DESCRIPTION("GPIO LED driver"); 297 MODULE_LICENSE("GPL"); 298 MODULE_ALIAS("platform:leds-gpio"); 299