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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/init.h>
 15 #include <linux/platform_device.h>
 16 #include <linux/gpio.h>
 17 #include <linux/leds.h>
 18 #include <linux/of.h>
 19 #include <linux/of_platform.h>
 20 #include <linux/of_gpio.h>
 21 #include <linux/slab.h>
 22 #include <linux/workqueue.h>
 23 #include <linux/module.h>
 24 #include <linux/err.h>
 25 
 26 struct gpio_led_data {
 27         struct led_classdev cdev;
 28         unsigned gpio;
 29         struct work_struct work;
 30         u8 new_level;
 31         u8 can_sleep;
 32         u8 active_low;
 33         u8 blinking;
 34         int (*platform_gpio_blink_set)(unsigned gpio, int state,
 35                         unsigned long *delay_on, unsigned long *delay_off);
 36 };
 37 
 38 static void gpio_led_work(struct work_struct *work)
 39 {
 40         struct gpio_led_data    *led_dat =
 41                 container_of(work, struct gpio_led_data, work);
 42 
 43         if (led_dat->blinking) {
 44                 led_dat->platform_gpio_blink_set(led_dat->gpio,
 45                                                  led_dat->new_level,
 46                                                  NULL, NULL);
 47                 led_dat->blinking = 0;
 48         } else
 49                 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
 50 }
 51 
 52 static void gpio_led_set(struct led_classdev *led_cdev,
 53         enum led_brightness value)
 54 {
 55         struct gpio_led_data *led_dat =
 56                 container_of(led_cdev, struct gpio_led_data, cdev);
 57         int level;
 58 
 59         if (value == LED_OFF)
 60                 level = 0;
 61         else
 62                 level = 1;
 63 
 64         if (led_dat->active_low)
 65                 level = !level;
 66 
 67         /* Setting GPIOs with I2C/etc requires a task context, and we don't
 68          * seem to have a reliable way to know if we're already in one; so
 69          * let's just assume the worst.
 70          */
 71         if (led_dat->can_sleep) {
 72                 led_dat->new_level = level;
 73                 schedule_work(&led_dat->work);
 74         } else {
 75                 if (led_dat->blinking) {
 76                         led_dat->platform_gpio_blink_set(led_dat->gpio, level,
 77                                                          NULL, NULL);
 78                         led_dat->blinking = 0;
 79                 } else
 80                         gpio_set_value(led_dat->gpio, level);
 81         }
 82 }
 83 
 84 static int gpio_blink_set(struct led_classdev *led_cdev,
 85         unsigned long *delay_on, unsigned long *delay_off)
 86 {
 87         struct gpio_led_data *led_dat =
 88                 container_of(led_cdev, struct gpio_led_data, cdev);
 89 
 90         led_dat->blinking = 1;
 91         return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
 92                                                 delay_on, delay_off);
 93 }
 94 
 95 static int create_gpio_led(const struct gpio_led *template,
 96         struct gpio_led_data *led_dat, struct device *parent,
 97         int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
 98 {
 99         int ret, state;
100 
101         led_dat->gpio = -1;
102 
103         /* skip leds that aren't available */
104         if (!gpio_is_valid(template->gpio)) {
105                 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
106                                 template->gpio, template->name);
107                 return 0;
108         }
109 
110         ret = devm_gpio_request(parent, template->gpio, template->name);
111         if (ret < 0)
112                 return ret;
113 
114         led_dat->cdev.name = template->name;
115         led_dat->cdev.default_trigger = template->default_trigger;
116         led_dat->gpio = template->gpio;
117         led_dat->can_sleep = gpio_cansleep(template->gpio);
118         led_dat->active_low = template->active_low;
119         led_dat->blinking = 0;
120         if (blink_set) {
121                 led_dat->platform_gpio_blink_set = blink_set;
122                 led_dat->cdev.blink_set = gpio_blink_set;
123         }
124         led_dat->cdev.brightness_set = gpio_led_set;
125         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
126                 state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low;
127         else
128                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
129         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
130         if (!template->retain_state_suspended)
131                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
132 
133         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
134         if (ret < 0)
135                 return ret;
136 
137         INIT_WORK(&led_dat->work, gpio_led_work);
138 
139         ret = led_classdev_register(parent, &led_dat->cdev);
140         if (ret < 0)
141                 return ret;
142 
143         return 0;
144 }
145 
146 static void delete_gpio_led(struct gpio_led_data *led)
147 {
148         if (!gpio_is_valid(led->gpio))
149                 return;
150         led_classdev_unregister(&led->cdev);
151         cancel_work_sync(&led->work);
152 }
153 
154 struct gpio_leds_priv {
155         int num_leds;
156         struct gpio_led_data leds[];
157 };
158 
159 static inline int sizeof_gpio_leds_priv(int num_leds)
160 {
161         return sizeof(struct gpio_leds_priv) +
162                 (sizeof(struct gpio_led_data) * num_leds);
163 }
164 
165 /* Code to create from OpenFirmware platform devices */
166 #ifdef CONFIG_OF_GPIO
167 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
168 {
169         struct device_node *np = pdev->dev.of_node, *child;
170         struct gpio_leds_priv *priv;
171         int count, ret;
172 
173         /* count LEDs in this device, so we know how much to allocate */
174         count = of_get_available_child_count(np);
175         if (!count)
176                 return ERR_PTR(-ENODEV);
177 
178         for_each_available_child_of_node(np, child)
179                 if (of_get_gpio(child, 0) == -EPROBE_DEFER)
180                         return ERR_PTR(-EPROBE_DEFER);
181 
182         priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count),
183                         GFP_KERNEL);
184         if (!priv)
185                 return ERR_PTR(-ENOMEM);
186 
187         for_each_available_child_of_node(np, child) {
188                 struct gpio_led led = {};
189                 enum of_gpio_flags flags;
190                 const char *state;
191 
192                 led.gpio = of_get_gpio_flags(child, 0, &flags);
193                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
194                 led.name = of_get_property(child, "label", NULL) ? : child->name;
195                 led.default_trigger =
196                         of_get_property(child, "linux,default-trigger", NULL);
197                 state = of_get_property(child, "default-state", NULL);
198                 if (state) {
199                         if (!strcmp(state, "keep"))
200                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
201                         else if (!strcmp(state, "on"))
202                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
203                         else
204                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
205                 }
206 
207                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
208                                       &pdev->dev, NULL);
209                 if (ret < 0) {
210                         of_node_put(child);
211                         goto err;
212                 }
213         }
214 
215         return priv;
216 
217 err:
218         for (count = priv->num_leds - 2; count >= 0; count--)
219                 delete_gpio_led(&priv->leds[count]);
220         return ERR_PTR(-ENODEV);
221 }
222 
223 static const struct of_device_id of_gpio_leds_match[] = {
224         { .compatible = "gpio-leds", },
225         {},
226 };
227 #else /* CONFIG_OF_GPIO */
228 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
229 {
230         return ERR_PTR(-ENODEV);
231 }
232 #endif /* CONFIG_OF_GPIO */
233 
234 
235 static int gpio_led_probe(struct platform_device *pdev)
236 {
237         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
238         struct gpio_leds_priv *priv;
239         int i, ret = 0;
240 
241 
242         if (pdata && pdata->num_leds) {
243                 priv = devm_kzalloc(&pdev->dev,
244                                 sizeof_gpio_leds_priv(pdata->num_leds),
245                                         GFP_KERNEL);
246                 if (!priv)
247                         return -ENOMEM;
248 
249                 priv->num_leds = pdata->num_leds;
250                 for (i = 0; i < priv->num_leds; i++) {
251                         ret = create_gpio_led(&pdata->leds[i],
252                                               &priv->leds[i],
253                                               &pdev->dev, pdata->gpio_blink_set);
254                         if (ret < 0) {
255                                 /* On failure: unwind the led creations */
256                                 for (i = i - 1; i >= 0; i--)
257                                         delete_gpio_led(&priv->leds[i]);
258                                 return ret;
259                         }
260                 }
261         } else {
262                 priv = gpio_leds_create_of(pdev);
263                 if (IS_ERR(priv))
264                         return PTR_ERR(priv);
265         }
266 
267         platform_set_drvdata(pdev, priv);
268 
269         return 0;
270 }
271 
272 static int gpio_led_remove(struct platform_device *pdev)
273 {
274         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
275         int i;
276 
277         for (i = 0; i < priv->num_leds; i++)
278                 delete_gpio_led(&priv->leds[i]);
279 
280         return 0;
281 }
282 
283 static struct platform_driver gpio_led_driver = {
284         .probe          = gpio_led_probe,
285         .remove         = gpio_led_remove,
286         .driver         = {
287                 .name   = "leds-gpio",
288                 .owner  = THIS_MODULE,
289                 .of_match_table = of_match_ptr(of_gpio_leds_match),
290         },
291 };
292 
293 module_platform_driver(gpio_led_driver);
294 
295 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
296 MODULE_DESCRIPTION("GPIO LED driver");
297 MODULE_LICENSE("GPL");
298 MODULE_ALIAS("platform:leds-gpio");
299 

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