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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/of.h>
 20 #include <linux/platform_device.h>
 21 #include <linux/property.h>
 22 #include <linux/slab.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         int (*platform_gpio_blink_set)(struct gpio_desc *desc, int state,
 30                         unsigned long *delay_on, unsigned long *delay_off);
 31 };
 32 
 33 static void gpio_led_set(struct led_classdev *led_cdev,
 34         enum led_brightness value)
 35 {
 36         struct gpio_led_data *led_dat =
 37                 container_of(led_cdev, struct gpio_led_data, 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 =
 68                 container_of(led_cdev, struct gpio_led_data, cdev);
 69 
 70         led_dat->blinking = 1;
 71         return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
 72                                                 delay_on, delay_off);
 73 }
 74 
 75 static int create_gpio_led(const struct gpio_led *template,
 76         struct gpio_led_data *led_dat, struct device *parent,
 77         int (*blink_set)(struct gpio_desc *, int, unsigned long *,
 78                          unsigned long *))
 79 {
 80         int ret, state;
 81 
 82         led_dat->gpiod = template->gpiod;
 83         if (!led_dat->gpiod) {
 84                 /*
 85                  * This is the legacy code path for platform code that
 86                  * still uses GPIO numbers. Ultimately we would like to get
 87                  * rid of this block completely.
 88                  */
 89                 unsigned long flags = GPIOF_OUT_INIT_LOW;
 90 
 91                 /* skip leds that aren't available */
 92                 if (!gpio_is_valid(template->gpio)) {
 93                         dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 94                                         template->gpio, template->name);
 95                         return 0;
 96                 }
 97 
 98                 if (template->active_low)
 99                         flags |= GPIOF_ACTIVE_LOW;
100 
101                 ret = devm_gpio_request_one(parent, template->gpio, flags,
102                                             template->name);
103                 if (ret < 0)
104                         return ret;
105 
106                 led_dat->gpiod = gpio_to_desc(template->gpio);
107                 if (!led_dat->gpiod)
108                         return -EINVAL;
109         }
110 
111         led_dat->cdev.name = template->name;
112         led_dat->cdev.default_trigger = template->default_trigger;
113         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
114         if (!led_dat->can_sleep)
115                 led_dat->cdev.brightness_set = gpio_led_set;
116         else
117                 led_dat->cdev.brightness_set_blocking = gpio_led_set_blocking;
118         led_dat->blinking = 0;
119         if (blink_set) {
120                 led_dat->platform_gpio_blink_set = blink_set;
121                 led_dat->cdev.blink_set = gpio_blink_set;
122         }
123         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
124                 state = !!gpiod_get_value_cansleep(led_dat->gpiod);
125         else
126                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
127         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
128         if (!template->retain_state_suspended)
129                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
130         if (template->panic_indicator)
131                 led_dat->cdev.flags |= LED_PANIC_INDICATOR;
132 
133         ret = gpiod_direction_output(led_dat->gpiod, state);
134         if (ret < 0)
135                 return ret;
136 
137         return led_classdev_register(parent, &led_dat->cdev);
138 }
139 
140 struct gpio_leds_priv {
141         int num_leds;
142         struct gpio_led_data leds[];
143 };
144 
145 static inline int sizeof_gpio_leds_priv(int num_leds)
146 {
147         return sizeof(struct gpio_leds_priv) +
148                 (sizeof(struct gpio_led_data) * num_leds);
149 }
150 
151 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
152 {
153         struct device *dev = &pdev->dev;
154         struct fwnode_handle *child;
155         struct gpio_leds_priv *priv;
156         int count, ret;
157         struct device_node *np;
158 
159         count = device_get_child_node_count(dev);
160         if (!count)
161                 return ERR_PTR(-ENODEV);
162 
163         priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
164         if (!priv)
165                 return ERR_PTR(-ENOMEM);
166 
167         device_for_each_child_node(dev, child) {
168                 struct gpio_led led = {};
169                 const char *state = NULL;
170 
171                 led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
172                 if (IS_ERR(led.gpiod)) {
173                         fwnode_handle_put(child);
174                         ret = PTR_ERR(led.gpiod);
175                         goto err;
176                 }
177 
178                 np = to_of_node(child);
179 
180                 if (fwnode_property_present(child, "label")) {
181                         fwnode_property_read_string(child, "label", &led.name);
182                 } else {
183                         if (IS_ENABLED(CONFIG_OF) && !led.name && np)
184                                 led.name = np->name;
185                         if (!led.name) {
186                                 ret = -EINVAL;
187                                 goto err;
188                         }
189                 }
190                 fwnode_property_read_string(child, "linux,default-trigger",
191                                             &led.default_trigger);
192 
193                 if (!fwnode_property_read_string(child, "default-state",
194                                                  &state)) {
195                         if (!strcmp(state, "keep"))
196                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
197                         else if (!strcmp(state, "on"))
198                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
199                         else
200                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
201                 }
202 
203                 if (fwnode_property_present(child, "retain-state-suspended"))
204                         led.retain_state_suspended = 1;
205                 if (fwnode_property_present(child, "panic-indicator"))
206                         led.panic_indicator = 1;
207 
208                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds],
209                                       dev, NULL);
210                 if (ret < 0) {
211                         fwnode_handle_put(child);
212                         goto err;
213                 }
214                 priv->num_leds++;
215         }
216 
217         return priv;
218 
219 err:
220         for (count = priv->num_leds - 1; count >= 0; count--)
221                 led_classdev_unregister(&priv->leds[count].cdev);
222         return ERR_PTR(ret);
223 }
224 
225 static const struct of_device_id of_gpio_leds_match[] = {
226         { .compatible = "gpio-leds", },
227         {},
228 };
229 
230 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
231 
232 static int gpio_led_probe(struct platform_device *pdev)
233 {
234         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
235         struct gpio_leds_priv *priv;
236         int i, ret = 0;
237 
238         if (pdata && pdata->num_leds) {
239                 priv = devm_kzalloc(&pdev->dev,
240                                 sizeof_gpio_leds_priv(pdata->num_leds),
241                                         GFP_KERNEL);
242                 if (!priv)
243                         return -ENOMEM;
244 
245                 priv->num_leds = pdata->num_leds;
246                 for (i = 0; i < priv->num_leds; i++) {
247                         ret = create_gpio_led(&pdata->leds[i],
248                                               &priv->leds[i],
249                                               &pdev->dev, pdata->gpio_blink_set);
250                         if (ret < 0) {
251                                 /* On failure: unwind the led creations */
252                                 for (i = i - 1; i >= 0; i--)
253                                         led_classdev_unregister(
254                                                         &priv->leds[i].cdev);
255                                 return ret;
256                         }
257                 }
258         } else {
259                 priv = gpio_leds_create(pdev);
260                 if (IS_ERR(priv))
261                         return PTR_ERR(priv);
262         }
263 
264         platform_set_drvdata(pdev, priv);
265 
266         return 0;
267 }
268 
269 static int gpio_led_remove(struct platform_device *pdev)
270 {
271         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
272         int i;
273 
274         for (i = 0; i < priv->num_leds; i++)
275                 led_classdev_unregister(&priv->leds[i].cdev);
276 
277         return 0;
278 }
279 
280 static void gpio_led_shutdown(struct platform_device *pdev)
281 {
282         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
283         int i;
284 
285         for (i = 0; i < priv->num_leds; i++) {
286                 struct gpio_led_data *led = &priv->leds[i];
287 
288                 gpio_led_set(&led->cdev, LED_OFF);
289         }
290 }
291 
292 static struct platform_driver gpio_led_driver = {
293         .probe          = gpio_led_probe,
294         .remove         = gpio_led_remove,
295         .shutdown       = gpio_led_shutdown,
296         .driver         = {
297                 .name   = "leds-gpio",
298                 .of_match_table = of_gpio_leds_match,
299         },
300 };
301 
302 module_platform_driver(gpio_led_driver);
303 
304 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
305 MODULE_DESCRIPTION("GPIO LED driver");
306 MODULE_LICENSE("GPL");
307 MODULE_ALIAS("platform:leds-gpio");
308 

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