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/container_of.h>
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/gpio.h>
  13 #include <linux/gpio/consumer.h>
  14 #include <linux/leds.h>
  15 #include <linux/mod_devicetable.h>
  16 #include <linux/module.h>
  17 #include <linux/overflow.h>
  18 #include <linux/pinctrl/consumer.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/property.h>
  21 #include <linux/slab.h>
  22 #include <linux/types.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 fwnode_handle *fwnode, gpio_blink_set_t blink_set)
  81 {
  82         struct led_init_data init_data = {};
  83         struct pinctrl *pinctrl;
  84         int ret, state;
  85
  86         led_dat->cdev.default_trigger = template->default_trigger;
  87         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
  88         if (!led_dat->can_sleep)
  89                 led_dat->cdev.brightness_set = gpio_led_set;
  90         else
  91                 led_dat->cdev.brightness_set_blocking = gpio_led_set_blocking;
  92         led_dat->blinking = 0;
  93         if (blink_set) {
  94                 led_dat->platform_gpio_blink_set = blink_set;
  95                 led_dat->cdev.blink_set = gpio_blink_set;
  96         }
  97         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) {
  98                 state = gpiod_get_value_cansleep(led_dat->gpiod);
  99                 if (state < 0)
 100                         return state;
 101         } else {
 102                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 103         }
 104         led_dat->cdev.brightness = state;
 105         led_dat->cdev.max_brightness = 1;
 106         if (!template->retain_state_suspended)
 107                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 108         if (template->panic_indicator)
 109                 led_dat->cdev.flags |= LED_PANIC_INDICATOR;
 110         if (template->retain_state_shutdown)
 111                 led_dat->cdev.flags |= LED_RETAIN_AT_SHUTDOWN;
 112
 113         ret = gpiod_direction_output(led_dat->gpiod, state);
 114         if (ret < 0)
 115                 return ret;
 116
 117         if (template->name) {
 118                 led_dat->cdev.name = template->name;
 119                 ret = devm_led_classdev_register(parent, &led_dat->cdev);
 120         } else {
 121                 init_data.fwnode = fwnode;
 122                 ret = devm_led_classdev_register_ext(parent, &led_dat->cdev,
 123                                                      &init_data);
 124         }
 125
 126         if (ret)
 127                 return ret;
 128
 129         pinctrl = devm_pinctrl_get_select_default(led_dat->cdev.dev);
 130         ret = PTR_ERR_OR_ZERO(pinctrl);
 131         /* pinctrl-%d not present, not an error */
 132         if (ret == -ENODEV)
 133                 ret = 0;
 134         if (ret) {
 135                 dev_warn(led_dat->cdev.dev, "Failed to select %pfw pinctrl: %d\n",
 136                          fwnode, ret);
 137         }
 138
 139         return ret;
 140 }
 141
 142 struct gpio_leds_priv {
 143         int num_leds;
 144         struct gpio_led_data leds[] __counted_by(num_leds);
 145 };
 146
 147 static struct gpio_leds_priv *gpio_leds_create(struct device *dev)
 148 {
 149         struct gpio_leds_priv *priv;
 150         int count, used, ret;
 151
 152         count = device_get_child_node_count(dev);
 153         if (!count)
 154                 return ERR_PTR(-ENODEV);
 155
 156         priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
 157         if (!priv)
 158                 return ERR_PTR(-ENOMEM);
 159         priv->num_leds = count;
 160         used = 0;
 161
 162         device_for_each_child_node_scoped(dev, child) {
 163                 struct gpio_led_data *led_dat = &priv->leds[used];
 164                 struct gpio_led led = {};
 165
 166                 /*
 167                  * Acquire gpiod from DT with uninitialized label, which
 168                  * will be updated after LED class device is registered,
 169                  * Only then the final LED name is known.
 170                  */
 171                 led.gpiod = devm_fwnode_gpiod_get(dev, child, NULL, GPIOD_ASIS,
 172                                                   NULL);
 173                 if (IS_ERR(led.gpiod)) {
 174                         dev_err_probe(dev, PTR_ERR(led.gpiod), "Failed to get GPIO '%pfw'\n",
 175                                       child);
 176                         return ERR_CAST(led.gpiod);
 177                 }
 178
 179                 led_dat->gpiod = led.gpiod;
 180
 181                 led.default_state = led_init_default_state_get(child);
 182
 183                 if (fwnode_property_present(child, "retain-state-suspended"))
 184                         led.retain_state_suspended = 1;
 185                 if (fwnode_property_present(child, "retain-state-shutdown"))
 186                         led.retain_state_shutdown = 1;
 187                 if (fwnode_property_present(child, "panic-indicator"))
 188                         led.panic_indicator = 1;
 189
 190                 ret = create_gpio_led(&led, led_dat, dev, child, NULL);
 191                 if (ret < 0)
 192                         return ERR_PTR(ret);
 193
 194                 /* Set gpiod label to match the corresponding LED name. */
 195                 gpiod_set_consumer_name(led_dat->gpiod,
 196                                         led_dat->cdev.dev->kobj.name);
 197                 used++;
 198         }
 199         priv->num_leds = used;
 200
 201         return priv;
 202 }
 203
 204 static const struct of_device_id of_gpio_leds_match[] = {
 205         { .compatible = "gpio-leds", },
 206         {},
 207 };
 208
 209 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 210
 211 static struct gpio_desc *gpio_led_get_gpiod(struct device *dev, int idx,
 212                                             const struct gpio_led *template)
 213 {
 214         struct gpio_desc *gpiod;
 215         int ret;
 216
 217         /*
 218          * This means the LED does not come from the device tree
 219          * or ACPI, so let's try just getting it by index from the
 220          * device, this will hit the board file, if any and get
 221          * the GPIO from there.
 222          */
 223         gpiod = devm_gpiod_get_index_optional(dev, NULL, idx, GPIOD_OUT_LOW);
 224         if (IS_ERR(gpiod))
 225                 return gpiod;
 226         if (gpiod) {
 227                 gpiod_set_consumer_name(gpiod, template->name);
 228                 return gpiod;
 229         }
 230
 231         /*
 232          * This is the legacy code path for platform code that
 233          * still uses GPIO numbers. Ultimately we would like to get
 234          * rid of this block completely.
 235          */
 236
 237         /* skip leds that aren't available */
 238         if (!gpio_is_valid(template->gpio))
 239                 return ERR_PTR(-ENOENT);
 240
 241         ret = devm_gpio_request_one(dev, template->gpio, GPIOF_OUT_INIT_LOW,
 242                                     template->name);
 243         if (ret < 0)
 244                 return ERR_PTR(ret);
 245
 246         gpiod = gpio_to_desc(template->gpio);
 247         if (!gpiod)
 248                 return ERR_PTR(-EINVAL);
 249
 250         if (template->active_low ^ gpiod_is_active_low(gpiod))
 251                 gpiod_toggle_active_low(gpiod);
 252
 253         return gpiod;
 254 }
 255
 256 static int gpio_led_probe(struct platform_device *pdev)
 257 {
 258         struct device *dev = &pdev->dev;
 259         struct gpio_led_platform_data *pdata = dev_get_platdata(dev);
 260         struct gpio_leds_priv *priv;
 261         int i, ret;
 262
 263         if (pdata && pdata->num_leds) {
 264                 priv = devm_kzalloc(dev, struct_size(priv, leds, pdata->num_leds), GFP_KERNEL);
 265                 if (!priv)
 266                         return -ENOMEM;
 267
 268                 priv->num_leds = pdata->num_leds;
 269                 for (i = 0; i < priv->num_leds; i++) {
 270                         const struct gpio_led *template = &pdata->leds[i];
 271                         struct gpio_led_data *led_dat = &priv->leds[i];
 272
 273                         if (template->gpiod)
 274                                 led_dat->gpiod = template->gpiod;
 275                         else
 276                                 led_dat->gpiod =
 277                                         gpio_led_get_gpiod(dev, i, template);
 278                         if (IS_ERR(led_dat->gpiod)) {
 279                                 dev_info(dev, "Skipping unavailable LED gpio %d (%s)\n",
 280                                          template->gpio, template->name);
 281                                 continue;
 282                         }
 283
 284                         ret = create_gpio_led(template, led_dat, dev, NULL,
 285                                               pdata->gpio_blink_set);
 286                         if (ret < 0)
 287                                 return ret;
 288                 }
 289         } else {
 290                 priv = gpio_leds_create(dev);
 291                 if (IS_ERR(priv))
 292                         return PTR_ERR(priv);
 293         }
 294
 295         platform_set_drvdata(pdev, priv);
 296
 297         return 0;
 298 }
 299
 300 static void gpio_led_shutdown(struct platform_device *pdev)
 301 {
 302         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 303         int i;
 304
 305         for (i = 0; i < priv->num_leds; i++) {
 306                 struct gpio_led_data *led = &priv->leds[i];
 307
 308                 if (!(led->cdev.flags & LED_RETAIN_AT_SHUTDOWN))
 309                         gpio_led_set(&led->cdev, LED_OFF);
 310         }
 311 }
 312
 313 static struct platform_driver gpio_led_driver = {
 314         .probe          = gpio_led_probe,
 315         .shutdown       = gpio_led_shutdown,
 316         .driver         = {
 317                 .name   = "leds-gpio",
 318                 .of_match_table = of_gpio_leds_match,
 319         },
 320 };
 321
 322 module_platform_driver(gpio_led_driver);
 323
 324 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 325 MODULE_DESCRIPTION("GPIO LED driver");
 326 MODULE_LICENSE("GPL");
 327 MODULE_ALIAS("platform:leds-gpio");