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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 = 0;
 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 (IS_ERR(led_dat->gpiod))
108                         return PTR_ERR(led_dat->gpiod);
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 
131         ret = gpiod_direction_output(led_dat->gpiod, state);
132         if (ret < 0)
133                 return ret;
134 
135         return led_classdev_register(parent, &led_dat->cdev);
136 }
137 
138 struct gpio_leds_priv {
139         int num_leds;
140         struct gpio_led_data leds[];
141 };
142 
143 static inline int sizeof_gpio_leds_priv(int num_leds)
144 {
145         return sizeof(struct gpio_leds_priv) +
146                 (sizeof(struct gpio_led_data) * num_leds);
147 }
148 
149 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
150 {
151         struct device *dev = &pdev->dev;
152         struct fwnode_handle *child;
153         struct gpio_leds_priv *priv;
154         int count, ret;
155         struct device_node *np;
156 
157         count = device_get_child_node_count(dev);
158         if (!count)
159                 return ERR_PTR(-ENODEV);
160 
161         priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
162         if (!priv)
163                 return ERR_PTR(-ENOMEM);
164 
165         device_for_each_child_node(dev, child) {
166                 struct gpio_led led = {};
167                 const char *state = NULL;
168 
169                 led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
170                 if (IS_ERR(led.gpiod)) {
171                         fwnode_handle_put(child);
172                         ret = PTR_ERR(led.gpiod);
173                         goto err;
174                 }
175 
176                 np = to_of_node(child);
177 
178                 if (fwnode_property_present(child, "label")) {
179                         fwnode_property_read_string(child, "label", &led.name);
180                 } else {
181                         if (IS_ENABLED(CONFIG_OF) && !led.name && np)
182                                 led.name = np->name;
183                         if (!led.name) {
184                                 ret = -EINVAL;
185                                 goto err;
186                         }
187                 }
188                 fwnode_property_read_string(child, "linux,default-trigger",
189                                             &led.default_trigger);
190 
191                 if (!fwnode_property_read_string(child, "default-state",
192                                                  &state)) {
193                         if (!strcmp(state, "keep"))
194                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
195                         else if (!strcmp(state, "on"))
196                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
197                         else
198                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
199                 }
200 
201                 if (fwnode_property_present(child, "retain-state-suspended"))
202                         led.retain_state_suspended = 1;
203 
204                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds],
205                                       dev, NULL);
206                 if (ret < 0) {
207                         fwnode_handle_put(child);
208                         goto err;
209                 }
210                 priv->num_leds++;
211         }
212 
213         return priv;
214 
215 err:
216         for (count = priv->num_leds - 1; count >= 0; count--)
217                 led_classdev_unregister(&priv->leds[count].cdev);
218         return ERR_PTR(ret);
219 }
220 
221 static const struct of_device_id of_gpio_leds_match[] = {
222         { .compatible = "gpio-leds", },
223         {},
224 };
225 
226 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
227 
228 static int gpio_led_probe(struct platform_device *pdev)
229 {
230         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
231         struct gpio_leds_priv *priv;
232         int i, ret = 0;
233 
234         if (pdata && pdata->num_leds) {
235                 priv = devm_kzalloc(&pdev->dev,
236                                 sizeof_gpio_leds_priv(pdata->num_leds),
237                                         GFP_KERNEL);
238                 if (!priv)
239                         return -ENOMEM;
240 
241                 priv->num_leds = pdata->num_leds;
242                 for (i = 0; i < priv->num_leds; i++) {
243                         ret = create_gpio_led(&pdata->leds[i],
244                                               &priv->leds[i],
245                                               &pdev->dev, pdata->gpio_blink_set);
246                         if (ret < 0) {
247                                 /* On failure: unwind the led creations */
248                                 for (i = i - 1; i >= 0; i--)
249                                         led_classdev_unregister(
250                                                         &priv->leds[i].cdev);
251                                 return ret;
252                         }
253                 }
254         } else {
255                 priv = gpio_leds_create(pdev);
256                 if (IS_ERR(priv))
257                         return PTR_ERR(priv);
258         }
259 
260         platform_set_drvdata(pdev, priv);
261 
262         return 0;
263 }
264 
265 static int gpio_led_remove(struct platform_device *pdev)
266 {
267         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
268         int i;
269 
270         for (i = 0; i < priv->num_leds; i++)
271                 led_classdev_unregister(&priv->leds[i].cdev);
272 
273         return 0;
274 }
275 
276 static void gpio_led_shutdown(struct platform_device *pdev)
277 {
278         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
279         int i;
280 
281         for (i = 0; i < priv->num_leds; i++) {
282                 struct gpio_led_data *led = &priv->leds[i];
283 
284                 gpio_led_set(&led->cdev, LED_OFF);
285         }
286 }
287 
288 static struct platform_driver gpio_led_driver = {
289         .probe          = gpio_led_probe,
290         .remove         = gpio_led_remove,
291         .shutdown       = gpio_led_shutdown,
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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