drivers/leds/leds-gpio.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * LEDs driver for GPIOs
   4  *
   5  * Copyright (C) 2007 8D Technologies inc.
   6  * Raphael Assenat <raph@8d.com>
   7  * Copyright (C) 2008 Freescale Semiconductor, Inc.
   8  */
   9 #include <linux/err.h>
  10 #include <linux/gpio.h>
  11 #include <linux/gpio/consumer.h>
  12 #include <linux/kernel.h>
  13 #include <linux/leds.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/property.h>
  18 #include <linux/slab.h>
  19
  20 struct gpio_led_data {
  21         struct led_classdev cdev;
  22         struct gpio_desc *gpiod;
  23         u8 can_sleep;
  24         u8 blinking;
  25         gpio_blink_set_t platform_gpio_blink_set;
  26 };
  27
  28 static inline struct gpio_led_data *
  29                         cdev_to_gpio_led_data(struct led_classdev *led_cdev)
  30 {
  31         return container_of(led_cdev, struct gpio_led_data, cdev);
  32 }
  33
  34 static void gpio_led_set(struct led_classdev *led_cdev,
  35         enum led_brightness value)
  36 {
  37         struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
  38         int level;
  39
  40         if (value == LED_OFF)
  41                 level = 0;
  42         else
  43                 level = 1;
  44
  45         if (led_dat->blinking) {
  46                 led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
  47                                                  NULL, NULL);
  48                 led_dat->blinking = 0;
  49         } else {
  50                 if (led_dat->can_sleep)
  51                         gpiod_set_value_cansleep(led_dat->gpiod, level);
  52                 else
  53                         gpiod_set_value(led_dat->gpiod, level);
  54         }
  55 }
  56
  57 static int gpio_led_set_blocking(struct led_classdev *led_cdev,
  58         enum led_brightness value)
  59 {
  60         gpio_led_set(led_cdev, value);
  61         return 0;
  62 }
  63
  64 static int gpio_blink_set(struct led_classdev *led_cdev,
  65         unsigned long *delay_on, unsigned long *delay_off)
  66 {
  67         struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
  68
  69         led_dat->blinking = 1;
  70         return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
  71                                                 delay_on, delay_off);
  72 }
  73
  74 static int create_gpio_led(const struct gpio_led *template,
  75         struct gpio_led_data *led_dat, struct device *parent,
  76         struct fwnode_handle *fwnode, gpio_blink_set_t blink_set)
  77 {
  78         struct led_init_data init_data = {};
  79         int ret, state;
  80
  81         led_dat->cdev.default_trigger = template->default_trigger;
  82         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
  83         if (!led_dat->can_sleep)
  84                 led_dat->cdev.brightness_set = gpio_led_set;
  85         else
  86                 led_dat->cdev.brightness_set_blocking = gpio_led_set_blocking;
  87         led_dat->blinking = 0;
  88         if (blink_set) {
  89                 led_dat->platform_gpio_blink_set = blink_set;
  90                 led_dat->cdev.blink_set = gpio_blink_set;
  91         }
  92         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) {
  93                 state = gpiod_get_value_cansleep(led_dat->gpiod);
  94                 if (state < 0)
  95                         return state;
  96         } else {
  97                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
  98         }
  99         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 100         if (!template->retain_state_suspended)
 101                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 102         if (template->panic_indicator)
 103                 led_dat->cdev.flags |= LED_PANIC_INDICATOR;
 104         if (template->retain_state_shutdown)
 105                 led_dat->cdev.flags |= LED_RETAIN_AT_SHUTDOWN;
 106
 107         ret = gpiod_direction_output(led_dat->gpiod, state);
 108         if (ret < 0)
 109                 return ret;
 110
 111         if (template->name) {
 112                 led_dat->cdev.name = template->name;
 113                 ret = devm_led_classdev_register(parent, &led_dat->cdev);
 114         } else {
 115                 init_data.fwnode = fwnode;
 116                 ret = devm_led_classdev_register_ext(parent, &led_dat->cdev,
 117                                                      &init_data);
 118         }
 119
 120         return ret;
 121 }
 122
 123 struct gpio_leds_priv {
 124         int num_leds;
 125         struct gpio_led_data leds[];
 126 };
 127
 128 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
 129 {
 130         struct device *dev = &pdev->dev;
 131         struct fwnode_handle *child;
 132         struct gpio_leds_priv *priv;
 133         int count, ret;
 134
 135         count = device_get_child_node_count(dev);
 136         if (!count)
 137                 return ERR_PTR(-ENODEV);
 138
 139         priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
 140         if (!priv)
 141                 return ERR_PTR(-ENOMEM);
 142
 143         device_for_each_child_node(dev, child) {
 144                 struct gpio_led_data *led_dat = &priv->leds[priv->num_leds];
 145                 struct gpio_led led = {};
 146                 const char *state = NULL;
 147
 148                 /*
 149                  * Acquire gpiod from DT with uninitialized label, which
 150                  * will be updated after LED class device is registered,
 151                  * Only then the final LED name is known.
 152                  */
 153                 led.gpiod = devm_fwnode_get_gpiod_from_child(dev, NULL, child,
 154                                                              GPIOD_ASIS,
 155                                                              NULL);
 156                 if (IS_ERR(led.gpiod)) {
 157                         fwnode_handle_put(child);
 158                         return ERR_CAST(led.gpiod);
 159                 }
 160
 161                 led_dat->gpiod = led.gpiod;
 162
 163                 if (!fwnode_property_read_string(child, "default-state",
 164                                                  &state)) {
 165                         if (!strcmp(state, "keep"))
 166                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 167                         else if (!strcmp(state, "on"))
 168                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 169                         else
 170                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 171                 }
 172
 173                 if (fwnode_property_present(child, "retain-state-suspended"))
 174                         led.retain_state_suspended = 1;
 175                 if (fwnode_property_present(child, "retain-state-shutdown"))
 176                         led.retain_state_shutdown = 1;
 177                 if (fwnode_property_present(child, "panic-indicator"))
 178                         led.panic_indicator = 1;
 179
 180                 ret = create_gpio_led(&led, led_dat, dev, child, NULL);
 181                 if (ret < 0) {
 182                         fwnode_handle_put(child);
 183                         return ERR_PTR(ret);
 184                 }
 185                 /* Set gpiod label to match the corresponding LED name. */
 186                 gpiod_set_consumer_name(led_dat->gpiod,
 187                                         led_dat->cdev.dev->kobj.name);
 188                 priv->num_leds++;
 189         }
 190
 191         return priv;
 192 }
 193
 194 static const struct of_device_id of_gpio_leds_match[] = {
 195         { .compatible = "gpio-leds", },
 196         {},
 197 };
 198
 199 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 200
 201 static struct gpio_desc *gpio_led_get_gpiod(struct device *dev, int idx,
 202                                             const struct gpio_led *template)
 203 {
 204         struct gpio_desc *gpiod;
 205         unsigned long flags = GPIOF_OUT_INIT_LOW;
 206         int ret;
 207
 208         /*
 209          * This means the LED does not come from the device tree
 210          * or ACPI, so let's try just getting it by index from the
 211          * device, this will hit the board file, if any and get
 212          * the GPIO from there.
 213          */
 214         gpiod = devm_gpiod_get_index(dev, NULL, idx, GPIOD_OUT_LOW);
 215         if (!IS_ERR(gpiod)) {
 216                 gpiod_set_consumer_name(gpiod, template->name);
 217                 return gpiod;
 218         }
 219         if (PTR_ERR(gpiod) != -ENOENT)
 220                 return gpiod;
 221
 222         /*
 223          * This is the legacy code path for platform code that
 224          * still uses GPIO numbers. Ultimately we would like to get
 225          * rid of this block completely.
 226          */
 227
 228         /* skip leds that aren't available */
 229         if (!gpio_is_valid(template->gpio))
 230                 return ERR_PTR(-ENOENT);
 231
 232         if (template->active_low)
 233                 flags |= GPIOF_ACTIVE_LOW;
 234
 235         ret = devm_gpio_request_one(dev, template->gpio, flags,
 236                                     template->name);
 237         if (ret < 0)
 238                 return ERR_PTR(ret);
 239
 240         gpiod = gpio_to_desc(template->gpio);
 241         if (!gpiod)
 242                 return ERR_PTR(-EINVAL);
 243
 244         return gpiod;
 245 }
 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, struct_size(priv, leds, pdata->num_leds),
 255                                     GFP_KERNEL);
 256                 if (!priv)
 257                         return -ENOMEM;
 258
 259                 priv->num_leds = pdata->num_leds;
 260                 for (i = 0; i < priv->num_leds; i++) {
 261                         const struct gpio_led *template = &pdata->leds[i];
 262                         struct gpio_led_data *led_dat = &priv->leds[i];
 263
 264                         if (template->gpiod)
 265                                 led_dat->gpiod = template->gpiod;
 266                         else
 267                                 led_dat->gpiod =
 268                                         gpio_led_get_gpiod(&pdev->dev,
 269                                                            i, template);
 270                         if (IS_ERR(led_dat->gpiod)) {
 271                                 dev_info(&pdev->dev, "Skipping unavailable LED gpio %d (%s)\n",
 272                                          template->gpio, template->name);
 273                                 continue;
 274                         }
 275
 276                         ret = create_gpio_led(template, led_dat,
 277                                               &pdev->dev, NULL,
 278                                               pdata->gpio_blink_set);
 279                         if (ret < 0)
 280                                 return ret;
 281                 }
 282         } else {
 283                 priv = gpio_leds_create(pdev);
 284                 if (IS_ERR(priv))
 285                         return PTR_ERR(priv);
 286         }
 287
 288         platform_set_drvdata(pdev, priv);
 289
 290         return 0;
 291 }
 292
 293 static void gpio_led_shutdown(struct platform_device *pdev)
 294 {
 295         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 296         int i;
 297
 298         for (i = 0; i < priv->num_leds; i++) {
 299                 struct gpio_led_data *led = &priv->leds[i];
 300
 301                 if (!(led->cdev.flags & LED_RETAIN_AT_SHUTDOWN))
 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         .shutdown       = gpio_led_shutdown,
 309         .driver         = {
 310                 .name   = "leds-gpio",
 311                 .of_match_table = of_gpio_leds_match,
 312         },
 313 };
 314
 315 module_platform_driver(gpio_led_driver);
 316
 317 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 318 MODULE_DESCRIPTION("GPIO LED driver");
 319 MODULE_LICENSE("GPL");
 320 MODULE_ALIAS("platform:leds-gpio");