Version:  2.0.40 2.2.26 2.4.37 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0

Linux/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                         ret = PTR_ERR(led.gpiod);
191                         goto err;
192                 }
193 
194                 np = of_node(child);
195 
196                 if (fwnode_property_present(child, "label")) {
197                         fwnode_property_read_string(child, "label", &led.name);
198                 } else {
199                         if (IS_ENABLED(CONFIG_OF) && !led.name && np)
200                                 led.name = np->name;
201                         if (!led.name)
202                                 return ERR_PTR(-EINVAL);
203                 }
204                 fwnode_property_read_string(child, "linux,default-trigger",
205                                             &led.default_trigger);
206 
207                 if (!fwnode_property_read_string(child, "default-state",
208                                                  &state)) {
209                         if (!strcmp(state, "keep"))
210                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
211                         else if (!strcmp(state, "on"))
212                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
213                         else
214                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
215                 }
216 
217                 if (fwnode_property_present(child, "retain-state-suspended"))
218                         led.retain_state_suspended = 1;
219 
220                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
221                                       dev, NULL);
222                 if (ret < 0) {
223                         fwnode_handle_put(child);
224                         goto err;
225                 }
226         }
227 
228         return priv;
229 
230 err:
231         for (count = priv->num_leds - 2; count >= 0; count--)
232                 delete_gpio_led(&priv->leds[count]);
233         return ERR_PTR(ret);
234 }
235 
236 static const struct of_device_id of_gpio_leds_match[] = {
237         { .compatible = "gpio-leds", },
238         {},
239 };
240 
241 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
242 
243 static int gpio_led_probe(struct platform_device *pdev)
244 {
245         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
246         struct gpio_leds_priv *priv;
247         int i, ret = 0;
248 
249         if (pdata && pdata->num_leds) {
250                 priv = devm_kzalloc(&pdev->dev,
251                                 sizeof_gpio_leds_priv(pdata->num_leds),
252                                         GFP_KERNEL);
253                 if (!priv)
254                         return -ENOMEM;
255 
256                 priv->num_leds = pdata->num_leds;
257                 for (i = 0; i < priv->num_leds; i++) {
258                         ret = create_gpio_led(&pdata->leds[i],
259                                               &priv->leds[i],
260                                               &pdev->dev, pdata->gpio_blink_set);
261                         if (ret < 0) {
262                                 /* On failure: unwind the led creations */
263                                 for (i = i - 1; i >= 0; i--)
264                                         delete_gpio_led(&priv->leds[i]);
265                                 return ret;
266                         }
267                 }
268         } else {
269                 priv = gpio_leds_create(pdev);
270                 if (IS_ERR(priv))
271                         return PTR_ERR(priv);
272         }
273 
274         platform_set_drvdata(pdev, priv);
275 
276         return 0;
277 }
278 
279 static int gpio_led_remove(struct platform_device *pdev)
280 {
281         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
282         int i;
283 
284         for (i = 0; i < priv->num_leds; i++)
285                 delete_gpio_led(&priv->leds[i]);
286 
287         return 0;
288 }
289 
290 static struct platform_driver gpio_led_driver = {
291         .probe          = gpio_led_probe,
292         .remove         = gpio_led_remove,
293         .driver         = {
294                 .name   = "leds-gpio",
295                 .of_match_table = of_gpio_leds_match,
296         },
297 };
298 
299 module_platform_driver(gpio_led_driver);
300 
301 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
302 MODULE_DESCRIPTION("GPIO LED driver");
303 MODULE_LICENSE("GPL");
304 MODULE_ALIAS("platform:leds-gpio");
305 

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