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/err.h> 14 #include <linux/gpio.h> 15 #include <linux/gpio/consumer.h> 16 #include <linux/kernel.h> 17 #include <linux/leds.h> 18 #include <linux/module.h> 19 #include <linux/of.h> 20 #include <linux/platform_device.h> 21 #include <linux/property.h> 22 #include <linux/slab.h> 23 #include <linux/workqueue.h> 24 25 struct gpio_led_data { 26 struct led_classdev cdev; 27 struct gpio_desc *gpiod; 28 struct work_struct work; 29 u8 new_level; 30 u8 can_sleep; 31 u8 blinking; 32 int (*platform_gpio_blink_set)(struct gpio_desc *desc, int state, 33 unsigned long *delay_on, unsigned long *delay_off); 34 }; 35 36 static void gpio_led_work(struct work_struct *work) 37 { 38 struct gpio_led_data *led_dat = 39 container_of(work, struct gpio_led_data, work); 40 41 if (led_dat->blinking) { 42 led_dat->platform_gpio_blink_set(led_dat->gpiod, 43 led_dat->new_level, NULL, NULL); 44 led_dat->blinking = 0; 45 } else 46 gpiod_set_value_cansleep(led_dat->gpiod, led_dat->new_level); 47 } 48 49 static void gpio_led_set(struct led_classdev *led_cdev, 50 enum led_brightness value) 51 { 52 struct gpio_led_data *led_dat = 53 container_of(led_cdev, struct gpio_led_data, cdev); 54 int level; 55 56 if (value == LED_OFF) 57 level = 0; 58 else 59 level = 1; 60 61 /* Setting GPIOs with I2C/etc requires a task context, and we don't 62 * seem to have a reliable way to know if we're already in one; so 63 * let's just assume the worst. 64 */ 65 if (led_dat->can_sleep) { 66 led_dat->new_level = level; 67 schedule_work(&led_dat->work); 68 } else { 69 if (led_dat->blinking) { 70 led_dat->platform_gpio_blink_set(led_dat->gpiod, level, 71 NULL, NULL); 72 led_dat->blinking = 0; 73 } else 74 gpiod_set_value(led_dat->gpiod, level); 75 } 76 } 77 78 static int gpio_blink_set(struct led_classdev *led_cdev, 79 unsigned long *delay_on, unsigned long *delay_off) 80 { 81 struct gpio_led_data *led_dat = 82 container_of(led_cdev, struct gpio_led_data, cdev); 83 84 led_dat->blinking = 1; 85 return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK, 86 delay_on, delay_off); 87 } 88 89 static int create_gpio_led(const struct gpio_led *template, 90 struct gpio_led_data *led_dat, struct device *parent, 91 int (*blink_set)(struct gpio_desc *, int, unsigned long *, 92 unsigned long *)) 93 { 94 int ret, state; 95 96 led_dat->gpiod = template->gpiod; 97 if (!led_dat->gpiod) { 98 /* 99 * This is the legacy code path for platform code that 100 * still uses GPIO numbers. Ultimately we would like to get 101 * rid of this block completely. 102 */ 103 unsigned long flags = 0; 104 105 /* skip leds that aren't available */ 106 if (!gpio_is_valid(template->gpio)) { 107 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n", 108 template->gpio, template->name); 109 return 0; 110 } 111 112 if (template->active_low) 113 flags |= GPIOF_ACTIVE_LOW; 114 115 ret = devm_gpio_request_one(parent, template->gpio, flags, 116 template->name); 117 if (ret < 0) 118 return ret; 119 120 led_dat->gpiod = gpio_to_desc(template->gpio); 121 if (IS_ERR(led_dat->gpiod)) 122 return PTR_ERR(led_dat->gpiod); 123 } 124 125 led_dat->cdev.name = template->name; 126 led_dat->cdev.default_trigger = template->default_trigger; 127 led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod); 128 led_dat->blinking = 0; 129 if (blink_set) { 130 led_dat->platform_gpio_blink_set = blink_set; 131 led_dat->cdev.blink_set = gpio_blink_set; 132 } 133 led_dat->cdev.brightness_set = gpio_led_set; 134 if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) 135 state = !!gpiod_get_value_cansleep(led_dat->gpiod); 136 else 137 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); 138 led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; 139 if (!template->retain_state_suspended) 140 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; 141 142 ret = gpiod_direction_output(led_dat->gpiod, state); 143 if (ret < 0) 144 return ret; 145 146 INIT_WORK(&led_dat->work, gpio_led_work); 147 148 return led_classdev_register(parent, &led_dat->cdev); 149 } 150 151 static void delete_gpio_led(struct gpio_led_data *led) 152 { 153 led_classdev_unregister(&led->cdev); 154 cancel_work_sync(&led->work); 155 } 156 157 struct gpio_leds_priv { 158 int num_leds; 159 struct gpio_led_data leds[]; 160 }; 161 162 static inline int sizeof_gpio_leds_priv(int num_leds) 163 { 164 return sizeof(struct gpio_leds_priv) + 165 (sizeof(struct gpio_led_data) * num_leds); 166 } 167 168 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev) 169 { 170 struct device *dev = &pdev->dev; 171 struct fwnode_handle *child; 172 struct gpio_leds_priv *priv; 173 int count, ret; 174 struct device_node *np; 175 176 count = device_get_child_node_count(dev); 177 if (!count) 178 return ERR_PTR(-ENODEV); 179 180 priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL); 181 if (!priv) 182 return ERR_PTR(-ENOMEM); 183 184 device_for_each_child_node(dev, child) { 185 struct gpio_led led = {}; 186 const char *state = NULL; 187 188 led.gpiod = devm_get_gpiod_from_child(dev, NULL, child); 189 if (IS_ERR(led.gpiod)) { 190 fwnode_handle_put(child); 191 ret = PTR_ERR(led.gpiod); 192 goto err; 193 } 194 195 np = to_of_node(child); 196 197 if (fwnode_property_present(child, "label")) { 198 fwnode_property_read_string(child, "label", &led.name); 199 } else { 200 if (IS_ENABLED(CONFIG_OF) && !led.name && np) 201 led.name = np->name; 202 if (!led.name) { 203 ret = -EINVAL; 204 goto err; 205 } 206 } 207 fwnode_property_read_string(child, "linux,default-trigger", 208 &led.default_trigger); 209 210 if (!fwnode_property_read_string(child, "default-state", 211 &state)) { 212 if (!strcmp(state, "keep")) 213 led.default_state = LEDS_GPIO_DEFSTATE_KEEP; 214 else if (!strcmp(state, "on")) 215 led.default_state = LEDS_GPIO_DEFSTATE_ON; 216 else 217 led.default_state = LEDS_GPIO_DEFSTATE_OFF; 218 } 219 220 if (fwnode_property_present(child, "retain-state-suspended")) 221 led.retain_state_suspended = 1; 222 223 ret = create_gpio_led(&led, &priv->leds[priv->num_leds], 224 dev, NULL); 225 if (ret < 0) { 226 fwnode_handle_put(child); 227 goto err; 228 } 229 priv->num_leds++; 230 } 231 232 return priv; 233 234 err: 235 for (count = priv->num_leds - 1; count >= 0; count--) 236 delete_gpio_led(&priv->leds[count]); 237 return ERR_PTR(ret); 238 } 239 240 static const struct of_device_id of_gpio_leds_match[] = { 241 { .compatible = "gpio-leds", }, 242 {}, 243 }; 244 245 MODULE_DEVICE_TABLE(of, of_gpio_leds_match); 246 247 static int gpio_led_probe(struct platform_device *pdev) 248 { 249 struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev); 250 struct gpio_leds_priv *priv; 251 int i, ret = 0; 252 253 if (pdata && pdata->num_leds) { 254 priv = devm_kzalloc(&pdev->dev, 255 sizeof_gpio_leds_priv(pdata->num_leds), 256 GFP_KERNEL); 257 if (!priv) 258 return -ENOMEM; 259 260 priv->num_leds = pdata->num_leds; 261 for (i = 0; i < priv->num_leds; i++) { 262 ret = create_gpio_led(&pdata->leds[i], 263 &priv->leds[i], 264 &pdev->dev, pdata->gpio_blink_set); 265 if (ret < 0) { 266 /* On failure: unwind the led creations */ 267 for (i = i - 1; i >= 0; i--) 268 delete_gpio_led(&priv->leds[i]); 269 return ret; 270 } 271 } 272 } else { 273 priv = gpio_leds_create(pdev); 274 if (IS_ERR(priv)) 275 return PTR_ERR(priv); 276 } 277 278 platform_set_drvdata(pdev, priv); 279 280 return 0; 281 } 282 283 static int gpio_led_remove(struct platform_device *pdev) 284 { 285 struct gpio_leds_priv *priv = platform_get_drvdata(pdev); 286 int i; 287 288 for (i = 0; i < priv->num_leds; i++) 289 delete_gpio_led(&priv->leds[i]); 290 291 return 0; 292 } 293 294 static void gpio_led_shutdown(struct platform_device *pdev) 295 { 296 struct gpio_leds_priv *priv = platform_get_drvdata(pdev); 297 int i; 298 299 for (i = 0; i < priv->num_leds; i++) { 300 struct gpio_led_data *led = &priv->leds[i]; 301 302 gpio_led_set(&led->cdev, LED_OFF); 303 } 304 } 305 306 static struct platform_driver gpio_led_driver = { 307 .probe = gpio_led_probe, 308 .remove = gpio_led_remove, 309 .shutdown = gpio_led_shutdown, 310 .driver = { 311 .name = "leds-gpio", 312 .of_match_table = of_gpio_leds_match, 313 }, 314 }; 315 316 module_platform_driver(gpio_led_driver); 317 318 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>"); 319 MODULE_DESCRIPTION("GPIO LED driver"); 320 MODULE_LICENSE("GPL"); 321 MODULE_ALIAS("platform:leds-gpio"); 322