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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                         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");
304 

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