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/platform_device.h>
  20 #include <linux/property.h>
  21 #include <linux/slab.h>
  22 #include <linux/workqueue.h>
  23
  24 struct gpio_led_data {
  25         struct led_classdev cdev;
  26         struct gpio_desc *gpiod;
  27         struct work_struct work;
  28         u8 new_level;
  29         u8 can_sleep;
  30         u8 blinking;
  31         int (*platform_gpio_blink_set)(struct gpio_desc *desc, int state,
  32                         unsigned long *delay_on, unsigned long *delay_off);
  33 };
  34
  35 static void gpio_led_work(struct work_struct *work)
  36 {
  37         struct gpio_led_data *led_dat =
  38                 container_of(work, struct gpio_led_data, work);
  39
  40         if (led_dat->blinking) {
  41                 led_dat->platform_gpio_blink_set(led_dat->gpiod,
  42                                         led_dat->new_level, NULL, NULL);
  43                 led_dat->blinking = 0;
  44         } else
  45                 gpiod_set_value_cansleep(led_dat->gpiod, led_dat->new_level);
  46 }
  47
  48 static void gpio_led_set(struct led_classdev *led_cdev,
  49         enum led_brightness value)
  50 {
  51         struct gpio_led_data *led_dat =
  52                 container_of(led_cdev, struct gpio_led_data, cdev);
  53         int level;
  54
  55         if (value == LED_OFF)
  56                 level = 0;
  57         else
  58                 level = 1;
  59
  60         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  61          * seem to have a reliable way to know if we're already in one; so
  62          * let's just assume the worst.
  63          */
  64         if (led_dat->can_sleep) {
  65                 led_dat->new_level = level;
  66                 schedule_work(&led_dat->work);
  67         } else {
  68                 if (led_dat->blinking) {
  69                         led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
  70                                                          NULL, NULL);
  71                         led_dat->blinking = 0;
  72                 } else
  73                         gpiod_set_value(led_dat->gpiod, level);
  74         }
  75 }
  76
  77 static int gpio_blink_set(struct led_classdev *led_cdev,
  78         unsigned long *delay_on, unsigned long *delay_off)
  79 {
  80         struct gpio_led_data *led_dat =
  81                 container_of(led_cdev, struct gpio_led_data, cdev);
  82
  83         led_dat->blinking = 1;
  84         return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
  85                                                 delay_on, delay_off);
  86 }
  87
  88 static int create_gpio_led(const struct gpio_led *template,
  89         struct gpio_led_data *led_dat, struct device *parent,
  90         int (*blink_set)(struct gpio_desc *, int, unsigned long *,
  91                          unsigned long *))
  92 {
  93         int ret, state;
  94
  95         led_dat->gpiod = template->gpiod;
  96         if (!led_dat->gpiod) {
  97                 /*
  98                  * This is the legacy code path for platform code that
  99                  * still uses GPIO numbers. Ultimately we would like to get
 100                  * rid of this block completely.
 101                  */
 102                 unsigned long flags = 0;
 103
 104                 /* skip leds that aren't available */
 105                 if (!gpio_is_valid(template->gpio)) {
 106                         dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 107                                         template->gpio, template->name);
 108                         return 0;
 109                 }
 110
 111                 if (template->active_low)
 112                         flags |= GPIOF_ACTIVE_LOW;
 113
 114                 ret = devm_gpio_request_one(parent, template->gpio, flags,
 115                                             template->name);
 116                 if (ret < 0)
 117                         return ret;
 118
 119                 led_dat->gpiod = gpio_to_desc(template->gpio);
 120                 if (IS_ERR(led_dat->gpiod))
 121                         return PTR_ERR(led_dat->gpiod);
 122         }
 123
 124         led_dat->cdev.name = template->name;
 125         led_dat->cdev.default_trigger = template->default_trigger;
 126         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
 127         led_dat->blinking = 0;
 128         if (blink_set) {
 129                 led_dat->platform_gpio_blink_set = blink_set;
 130                 led_dat->cdev.blink_set = gpio_blink_set;
 131         }
 132         led_dat->cdev.brightness_set = gpio_led_set;
 133         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 134                 state = !!gpiod_get_value_cansleep(led_dat->gpiod);
 135         else
 136                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 137         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 138         if (!template->retain_state_suspended)
 139                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 140
 141         ret = gpiod_direction_output(led_dat->gpiod, state);
 142         if (ret < 0)
 143                 return ret;
 144
 145         INIT_WORK(&led_dat->work, gpio_led_work);
 146
 147         return led_classdev_register(parent, &led_dat->cdev);
 148 }
 149
 150 static void delete_gpio_led(struct gpio_led_data *led)
 151 {
 152         led_classdev_unregister(&led->cdev);
 153         cancel_work_sync(&led->work);
 154 }
 155
 156 struct gpio_leds_priv {
 157         int num_leds;
 158         struct gpio_led_data leds[];
 159 };
 160
 161 static inline int sizeof_gpio_leds_priv(int num_leds)
 162 {
 163         return sizeof(struct gpio_leds_priv) +
 164                 (sizeof(struct gpio_led_data) * num_leds);
 165 }
 166
 167 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
 168 {
 169         struct device *dev = &pdev->dev;
 170         struct fwnode_handle *child;
 171         struct gpio_leds_priv *priv;
 172         int count, ret;
 173         struct device_node *np;
 174
 175         count = device_get_child_node_count(dev);
 176         if (!count)
 177                 return ERR_PTR(-ENODEV);
 178
 179         priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
 180         if (!priv)
 181                 return ERR_PTR(-ENOMEM);
 182
 183         device_for_each_child_node(dev, child) {
 184                 struct gpio_led led = {};
 185                 const char *state = NULL;
 186
 187                 led.gpiod = devm_get_gpiod_from_child(dev, child);
 188                 if (IS_ERR(led.gpiod)) {
 189                         fwnode_handle_put(child);
 190                         goto err;
 191                 }
 192
 193                 np = of_node(child);
 194
 195                 if (fwnode_property_present(child, "label")) {
 196                         fwnode_property_read_string(child, "label", &led.name);
 197                 } else {
 198                         if (IS_ENABLED(CONFIG_OF) && !led.name && np)
 199                                 led.name = np->name;
 200                         if (!led.name)
 201                                 return ERR_PTR(-EINVAL);
 202                 }
 203                 fwnode_property_read_string(child, "linux,default-trigger",
 204                                             &led.default_trigger);
 205
 206                 if (!fwnode_property_read_string(child, "default-state",
 207                                                  &state)) {
 208                         if (!strcmp(state, "keep"))
 209                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 210                         else if (!strcmp(state, "on"))
 211                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 212                         else
 213                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 214                 }
 215
 216                 if (fwnode_property_present(child, "retain-state-suspended"))
 217                         led.retain_state_suspended = 1;
 218
 219                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
 220                                       dev, NULL);
 221                 if (ret < 0) {
 222                         fwnode_handle_put(child);
 223                         goto err;
 224                 }
 225         }
 226
 227         return priv;
 228
 229 err:
 230         for (count = priv->num_leds - 2; count >= 0; count--)
 231                 delete_gpio_led(&priv->leds[count]);
 232         return ERR_PTR(-ENODEV);
 233 }
 234
 235 static const struct of_device_id of_gpio_leds_match[] = {
 236         { .compatible = "gpio-leds", },
 237         {},
 238 };
 239
 240 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 241
 242 static int gpio_led_probe(struct platform_device *pdev)
 243 {
 244         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
 245         struct gpio_leds_priv *priv;
 246         int i, ret = 0;
 247
 248         if (pdata && pdata->num_leds) {
 249                 priv = devm_kzalloc(&pdev->dev,
 250                                 sizeof_gpio_leds_priv(pdata->num_leds),
 251                                         GFP_KERNEL);
 252                 if (!priv)
 253                         return -ENOMEM;
 254
 255                 priv->num_leds = pdata->num_leds;
 256                 for (i = 0; i < priv->num_leds; i++) {
 257                         ret = create_gpio_led(&pdata->leds[i],
 258                                               &priv->leds[i],
 259                                               &pdev->dev, pdata->gpio_blink_set);
 260                         if (ret < 0) {
 261                                 /* On failure: unwind the led creations */
 262                                 for (i = i - 1; i >= 0; i--)
 263                                         delete_gpio_led(&priv->leds[i]);
 264                                 return ret;
 265                         }
 266                 }
 267         } else {
 268                 priv = gpio_leds_create(pdev);
 269                 if (IS_ERR(priv))
 270                         return PTR_ERR(priv);
 271         }
 272
 273         platform_set_drvdata(pdev, priv);
 274
 275         return 0;
 276 }
 277
 278 static int gpio_led_remove(struct platform_device *pdev)
 279 {
 280         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 281         int i;
 282
 283         for (i = 0; i < priv->num_leds; i++)
 284                 delete_gpio_led(&priv->leds[i]);
 285
 286         return 0;
 287 }
 288
 289 static struct platform_driver gpio_led_driver = {
 290         .probe          = gpio_led_probe,
 291         .remove         = gpio_led_remove,
 292         .driver         = {
 293                 .name   = "leds-gpio",
 294                 .of_match_table = of_gpio_leds_match,
 295         },
 296 };
 297
 298 module_platform_driver(gpio_led_driver);
 299
 300 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 301 MODULE_DESCRIPTION("GPIO LED driver");
 302 MODULE_LICENSE("GPL");
 303 MODULE_ALIAS("platform:leds-gpio");