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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/kernel.h>
 14 #include <linux/platform_device.h>
 15 #include <linux/gpio.h>
 16 #include <linux/leds.h>
 17 #include <linux/of.h>
 18 #include <linux/of_platform.h>
 19 #include <linux/of_gpio.h>
 20 #include <linux/slab.h>
 21 #include <linux/workqueue.h>
 22 #include <linux/module.h>
 23 #include <linux/err.h>
 24 
 25 struct gpio_led_data {
 26         struct led_classdev cdev;
 27         unsigned gpio;
 28         struct work_struct work;
 29         u8 new_level;
 30         u8 can_sleep;
 31         u8 active_low;
 32         u8 blinking;
 33         int (*platform_gpio_blink_set)(unsigned gpio, int state,
 34                         unsigned long *delay_on, unsigned long *delay_off);
 35 };
 36 
 37 static void gpio_led_work(struct work_struct *work)
 38 {
 39         struct gpio_led_data    *led_dat =
 40                 container_of(work, struct gpio_led_data, work);
 41 
 42         if (led_dat->blinking) {
 43                 led_dat->platform_gpio_blink_set(led_dat->gpio,
 44                                                  led_dat->new_level,
 45                                                  NULL, NULL);
 46                 led_dat->blinking = 0;
 47         } else
 48                 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
 49 }
 50 
 51 static void gpio_led_set(struct led_classdev *led_cdev,
 52         enum led_brightness value)
 53 {
 54         struct gpio_led_data *led_dat =
 55                 container_of(led_cdev, struct gpio_led_data, cdev);
 56         int level;
 57 
 58         if (value == LED_OFF)
 59                 level = 0;
 60         else
 61                 level = 1;
 62 
 63         if (led_dat->active_low)
 64                 level = !level;
 65 
 66         /* Setting GPIOs with I2C/etc requires a task context, and we don't
 67          * seem to have a reliable way to know if we're already in one; so
 68          * let's just assume the worst.
 69          */
 70         if (led_dat->can_sleep) {
 71                 led_dat->new_level = level;
 72                 schedule_work(&led_dat->work);
 73         } else {
 74                 if (led_dat->blinking) {
 75                         led_dat->platform_gpio_blink_set(led_dat->gpio, level,
 76                                                          NULL, NULL);
 77                         led_dat->blinking = 0;
 78                 } else
 79                         gpio_set_value(led_dat->gpio, level);
 80         }
 81 }
 82 
 83 static int gpio_blink_set(struct led_classdev *led_cdev,
 84         unsigned long *delay_on, unsigned long *delay_off)
 85 {
 86         struct gpio_led_data *led_dat =
 87                 container_of(led_cdev, struct gpio_led_data, cdev);
 88 
 89         led_dat->blinking = 1;
 90         return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
 91                                                 delay_on, delay_off);
 92 }
 93 
 94 static int create_gpio_led(const struct gpio_led *template,
 95         struct gpio_led_data *led_dat, struct device *parent,
 96         int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
 97 {
 98         int ret, state;
 99 
100         led_dat->gpio = -1;
101 
102         /* skip leds that aren't available */
103         if (!gpio_is_valid(template->gpio)) {
104                 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
105                                 template->gpio, template->name);
106                 return 0;
107         }
108 
109         ret = devm_gpio_request(parent, template->gpio, template->name);
110         if (ret < 0)
111                 return ret;
112 
113         led_dat->cdev.name = template->name;
114         led_dat->cdev.default_trigger = template->default_trigger;
115         led_dat->gpio = template->gpio;
116         led_dat->can_sleep = gpio_cansleep(template->gpio);
117         led_dat->active_low = template->active_low;
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         led_dat->cdev.brightness_set = gpio_led_set;
124         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
125                 state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low;
126         else
127                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
128         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
129         if (!template->retain_state_suspended)
130                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
131 
132         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
133         if (ret < 0)
134                 return ret;
135 
136         INIT_WORK(&led_dat->work, gpio_led_work);
137 
138         ret = led_classdev_register(parent, &led_dat->cdev);
139         if (ret < 0)
140                 return ret;
141 
142         return 0;
143 }
144 
145 static void delete_gpio_led(struct gpio_led_data *led)
146 {
147         if (!gpio_is_valid(led->gpio))
148                 return;
149         led_classdev_unregister(&led->cdev);
150         cancel_work_sync(&led->work);
151 }
152 
153 struct gpio_leds_priv {
154         int num_leds;
155         struct gpio_led_data leds[];
156 };
157 
158 static inline int sizeof_gpio_leds_priv(int num_leds)
159 {
160         return sizeof(struct gpio_leds_priv) +
161                 (sizeof(struct gpio_led_data) * num_leds);
162 }
163 
164 /* Code to create from OpenFirmware platform devices */
165 #ifdef CONFIG_OF_GPIO
166 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
167 {
168         struct device_node *np = pdev->dev.of_node, *child;
169         struct gpio_leds_priv *priv;
170         int count, ret;
171 
172         /* count LEDs in this device, so we know how much to allocate */
173         count = of_get_available_child_count(np);
174         if (!count)
175                 return ERR_PTR(-ENODEV);
176 
177         for_each_available_child_of_node(np, child)
178                 if (of_get_gpio(child, 0) == -EPROBE_DEFER)
179                         return ERR_PTR(-EPROBE_DEFER);
180 
181         priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count),
182                         GFP_KERNEL);
183         if (!priv)
184                 return ERR_PTR(-ENOMEM);
185 
186         for_each_available_child_of_node(np, child) {
187                 struct gpio_led led = {};
188                 enum of_gpio_flags flags;
189                 const char *state;
190 
191                 led.gpio = of_get_gpio_flags(child, 0, &flags);
192                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
193                 led.name = of_get_property(child, "label", NULL) ? : child->name;
194                 led.default_trigger =
195                         of_get_property(child, "linux,default-trigger", NULL);
196                 state = of_get_property(child, "default-state", NULL);
197                 if (state) {
198                         if (!strcmp(state, "keep"))
199                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
200                         else if (!strcmp(state, "on"))
201                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
202                         else
203                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
204                 }
205 
206                 if (of_get_property(child, "retain-state-suspended", NULL))
207                         led.retain_state_suspended = 1;
208 
209                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
210                                       &pdev->dev, NULL);
211                 if (ret < 0) {
212                         of_node_put(child);
213                         goto err;
214                 }
215         }
216 
217         return priv;
218 
219 err:
220         for (count = priv->num_leds - 2; count >= 0; count--)
221                 delete_gpio_led(&priv->leds[count]);
222         return ERR_PTR(-ENODEV);
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 #else /* CONFIG_OF_GPIO */
232 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
233 {
234         return ERR_PTR(-ENODEV);
235 }
236 #endif /* CONFIG_OF_GPIO */
237 
238 
239 static int gpio_led_probe(struct platform_device *pdev)
240 {
241         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
242         struct gpio_leds_priv *priv;
243         int i, ret = 0;
244 
245 
246         if (pdata && pdata->num_leds) {
247                 priv = devm_kzalloc(&pdev->dev,
248                                 sizeof_gpio_leds_priv(pdata->num_leds),
249                                         GFP_KERNEL);
250                 if (!priv)
251                         return -ENOMEM;
252 
253                 priv->num_leds = pdata->num_leds;
254                 for (i = 0; i < priv->num_leds; i++) {
255                         ret = create_gpio_led(&pdata->leds[i],
256                                               &priv->leds[i],
257                                               &pdev->dev, pdata->gpio_blink_set);
258                         if (ret < 0) {
259                                 /* On failure: unwind the led creations */
260                                 for (i = i - 1; i >= 0; i--)
261                                         delete_gpio_led(&priv->leds[i]);
262                                 return ret;
263                         }
264                 }
265         } else {
266                 priv = gpio_leds_create_of(pdev);
267                 if (IS_ERR(priv))
268                         return PTR_ERR(priv);
269         }
270 
271         platform_set_drvdata(pdev, priv);
272 
273         return 0;
274 }
275 
276 static int gpio_led_remove(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                 delete_gpio_led(&priv->leds[i]);
283 
284         return 0;
285 }
286 
287 static struct platform_driver gpio_led_driver = {
288         .probe          = gpio_led_probe,
289         .remove         = gpio_led_remove,
290         .driver         = {
291                 .name   = "leds-gpio",
292                 .owner  = THIS_MODULE,
293                 .of_match_table = of_match_ptr(of_gpio_leds_match),
294         },
295 };
296 
297 module_platform_driver(gpio_led_driver);
298 
299 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
300 MODULE_DESCRIPTION("GPIO LED driver");
301 MODULE_LICENSE("GPL");
302 MODULE_ALIAS("platform:leds-gpio");
303 

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