drivers/leds/leds-gpio.c

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