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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         gpio_blink_set_t platform_gpio_blink_set;
 30 };
 31 
 32 static inline struct gpio_led_data *
 33                         cdev_to_gpio_led_data(struct led_classdev *led_cdev)
 34 {
 35         return container_of(led_cdev, struct gpio_led_data, cdev);
 36 }
 37 
 38 static void gpio_led_set(struct led_classdev *led_cdev,
 39         enum led_brightness value)
 40 {
 41         struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
 42         int level;
 43 
 44         if (value == LED_OFF)
 45                 level = 0;
 46         else
 47                 level = 1;
 48 
 49         if (led_dat->blinking) {
 50                 led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
 51                                                  NULL, NULL);
 52                 led_dat->blinking = 0;
 53         } else {
 54                 if (led_dat->can_sleep)
 55                         gpiod_set_value_cansleep(led_dat->gpiod, level);
 56                 else
 57                         gpiod_set_value(led_dat->gpiod, level);
 58         }
 59 }
 60 
 61 static int gpio_led_set_blocking(struct led_classdev *led_cdev,
 62         enum led_brightness value)
 63 {
 64         gpio_led_set(led_cdev, value);
 65         return 0;
 66 }
 67 
 68 static int gpio_blink_set(struct led_classdev *led_cdev,
 69         unsigned long *delay_on, unsigned long *delay_off)
 70 {
 71         struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
 72 
 73         led_dat->blinking = 1;
 74         return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
 75                                                 delay_on, delay_off);
 76 }
 77 
 78 static int create_gpio_led(const struct gpio_led *template,
 79         struct gpio_led_data *led_dat, struct device *parent,
 80         gpio_blink_set_t blink_set)
 81 {
 82         int ret, state;
 83 
 84         led_dat->gpiod = template->gpiod;
 85         if (!led_dat->gpiod) {
 86                 /*
 87                  * This is the legacy code path for platform code that
 88                  * still uses GPIO numbers. Ultimately we would like to get
 89                  * rid of this block completely.
 90                  */
 91                 unsigned long flags = GPIOF_OUT_INIT_LOW;
 92 
 93                 /* skip leds that aren't available */
 94                 if (!gpio_is_valid(template->gpio)) {
 95                         dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 96                                         template->gpio, template->name);
 97                         return 0;
 98                 }
 99 
100                 if (template->active_low)
101                         flags |= GPIOF_ACTIVE_LOW;
102 
103                 ret = devm_gpio_request_one(parent, template->gpio, flags,
104                                             template->name);
105                 if (ret < 0)
106                         return ret;
107 
108                 led_dat->gpiod = gpio_to_desc(template->gpio);
109                 if (!led_dat->gpiod)
110                         return -EINVAL;
111         }
112 
113         led_dat->cdev.name = template->name;
114         led_dat->cdev.default_trigger = template->default_trigger;
115         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
116         if (!led_dat->can_sleep)
117                 led_dat->cdev.brightness_set = gpio_led_set;
118         else
119                 led_dat->cdev.brightness_set_blocking = gpio_led_set_blocking;
120         led_dat->blinking = 0;
121         if (blink_set) {
122                 led_dat->platform_gpio_blink_set = blink_set;
123                 led_dat->cdev.blink_set = gpio_blink_set;
124         }
125         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) {
126                 state = gpiod_get_value_cansleep(led_dat->gpiod);
127                 if (state < 0)
128                         return state;
129         } else {
130                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
131         }
132         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
133         if (!template->retain_state_suspended)
134                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
135         if (template->panic_indicator)
136                 led_dat->cdev.flags |= LED_PANIC_INDICATOR;
137 
138         ret = gpiod_direction_output(led_dat->gpiod, state);
139         if (ret < 0)
140                 return ret;
141 
142         return devm_led_classdev_register(parent, &led_dat->cdev);
143 }
144 
145 struct gpio_leds_priv {
146         int num_leds;
147         struct gpio_led_data leds[];
148 };
149 
150 static inline int sizeof_gpio_leds_priv(int num_leds)
151 {
152         return sizeof(struct gpio_leds_priv) +
153                 (sizeof(struct gpio_led_data) * num_leds);
154 }
155 
156 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
157 {
158         struct device *dev = &pdev->dev;
159         struct fwnode_handle *child;
160         struct gpio_leds_priv *priv;
161         int count, ret;
162 
163         count = device_get_child_node_count(dev);
164         if (!count)
165                 return ERR_PTR(-ENODEV);
166 
167         priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
168         if (!priv)
169                 return ERR_PTR(-ENOMEM);
170 
171         device_for_each_child_node(dev, child) {
172                 struct gpio_led_data *led_dat = &priv->leds[priv->num_leds];
173                 struct gpio_led led = {};
174                 const char *state = NULL;
175                 struct device_node *np = to_of_node(child);
176 
177                 led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
178                 if (IS_ERR(led.gpiod)) {
179                         fwnode_handle_put(child);
180                         return ERR_CAST(led.gpiod);
181                 }
182 
183                 ret = fwnode_property_read_string(child, "label", &led.name);
184                 if (ret && IS_ENABLED(CONFIG_OF) && np)
185                         led.name = np->name;
186                 if (!led.name) {
187                         fwnode_handle_put(child);
188                         return ERR_PTR(-EINVAL);
189                 }
190 
191                 fwnode_property_read_string(child, "linux,default-trigger",
192                                             &led.default_trigger);
193 
194                 if (!fwnode_property_read_string(child, "default-state",
195                                                  &state)) {
196                         if (!strcmp(state, "keep"))
197                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
198                         else if (!strcmp(state, "on"))
199                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
200                         else
201                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
202                 }
203 
204                 if (fwnode_property_present(child, "retain-state-suspended"))
205                         led.retain_state_suspended = 1;
206                 if (fwnode_property_present(child, "panic-indicator"))
207                         led.panic_indicator = 1;
208 
209                 ret = create_gpio_led(&led, led_dat, dev, NULL);
210                 if (ret < 0) {
211                         fwnode_handle_put(child);
212                         return ERR_PTR(ret);
213                 }
214                 led_dat->cdev.dev->of_node = np;
215                 priv->num_leds++;
216         }
217 
218         return priv;
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                                 return ret;
248                 }
249         } else {
250                 priv = gpio_leds_create(pdev);
251                 if (IS_ERR(priv))
252                         return PTR_ERR(priv);
253         }
254 
255         platform_set_drvdata(pdev, priv);
256 
257         return 0;
258 }
259 
260 static void gpio_led_shutdown(struct platform_device *pdev)
261 {
262         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
263         int i;
264 
265         for (i = 0; i < priv->num_leds; i++) {
266                 struct gpio_led_data *led = &priv->leds[i];
267 
268                 gpio_led_set(&led->cdev, LED_OFF);
269         }
270 }
271 
272 static struct platform_driver gpio_led_driver = {
273         .probe          = gpio_led_probe,
274         .shutdown       = gpio_led_shutdown,
275         .driver         = {
276                 .name   = "leds-gpio",
277                 .of_match_table = of_gpio_leds_match,
278         },
279 };
280 
281 module_platform_driver(gpio_led_driver);
282 
283 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
284 MODULE_DESCRIPTION("GPIO LED driver");
285 MODULE_LICENSE("GPL");
286 MODULE_ALIAS("platform:leds-gpio");
287 

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