/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/leds.h>
 17#include <linux/of_platform.h>
 18#include <linux/of_gpio.h>
 19#include <linux/slab.h>
 20#include <linux/workqueue.h>
 21
 22#include <asm/gpio.h>
 23
 24struct gpio_led_data {
 25	struct led_classdev cdev;
 26	unsigned gpio;
 27	struct work_struct work;
 28	u8 new_level;
 29	u8 can_sleep;
 30	u8 active_low;
 31	u8 blinking;
 32	int (*platform_gpio_blink_set)(unsigned gpio, int state,
 33			unsigned long *delay_on, unsigned long *delay_off);
 34};
 35
 36static void gpio_led_work(struct work_struct *work)
 37{
 38	struct gpio_led_data	*led_dat =
 39		container_of(work, struct gpio_led_data, work);
 40
 41	if (led_dat->blinking) {
 42		led_dat->platform_gpio_blink_set(led_dat->gpio,
 43						 led_dat->new_level,
 44						 NULL, NULL);
 45		led_dat->blinking = 0;
 46	} else
 47		gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
 48}
 49
 50static void gpio_led_set(struct led_classdev *led_cdev,
 51	enum led_brightness value)
 52{
 53	struct gpio_led_data *led_dat =
 54		container_of(led_cdev, struct gpio_led_data, cdev);
 55	int level;
 56
 57	if (value == LED_OFF)
 58		level = 0;
 59	else
 60		level = 1;
 61
 62	if (led_dat->active_low)
 63		level = !level;
 64
 65	/* Setting GPIOs with I2C/etc requires a task context, and we don't
 66	 * seem to have a reliable way to know if we're already in one; so
 67	 * let's just assume the worst.
 68	 */
 69	if (led_dat->can_sleep) {
 70		led_dat->new_level = level;
 71		schedule_work(&led_dat->work);
 72	} else {
 73		if (led_dat->blinking) {
 74			led_dat->platform_gpio_blink_set(led_dat->gpio, level,
 75							 NULL, NULL);
 76			led_dat->blinking = 0;
 77		} else
 78			gpio_set_value(led_dat->gpio, level);
 79	}
 80}
 81
 82static int gpio_blink_set(struct led_classdev *led_cdev,
 83	unsigned long *delay_on, unsigned long *delay_off)
 84{
 85	struct gpio_led_data *led_dat =
 86		container_of(led_cdev, struct gpio_led_data, cdev);
 87
 88	led_dat->blinking = 1;
 89	return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
 90						delay_on, delay_off);
 91}
 92
 93static int __devinit create_gpio_led(const struct gpio_led *template,
 94	struct gpio_led_data *led_dat, struct device *parent,
 95	int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
 96{
 97	int ret, state;
 98
 99	led_dat->gpio = -1;
100
101	/* skip leds that aren't available */
102	if (!gpio_is_valid(template->gpio)) {
103		printk(KERN_INFO "Skipping unavailable LED gpio %d (%s)\n",
104				template->gpio, template->name);
105		return 0;
106	}
107
108	ret = gpio_request(template->gpio, template->name);
109	if (ret < 0)
110		return ret;
111
112	led_dat->cdev.name = template->name;
113	led_dat->cdev.default_trigger = template->default_trigger;
114	led_dat->gpio = template->gpio;
115	led_dat->can_sleep = gpio_cansleep(template->gpio);
116	led_dat->active_low = template->active_low;
117	led_dat->blinking = 0;
118	if (blink_set) {
119		led_dat->platform_gpio_blink_set = blink_set;
120		led_dat->cdev.blink_set = gpio_blink_set;
121	}
122	led_dat->cdev.brightness_set = gpio_led_set;
123	if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
124		state = !!gpio_get_value(led_dat->gpio) ^ led_dat->active_low;
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 = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
132	if (ret < 0)
133		goto err;
134		
135	INIT_WORK(&led_dat->work, gpio_led_work);
136
137	ret = led_classdev_register(parent, &led_dat->cdev);
138	if (ret < 0)
139		goto err;
140
141	return 0;
142err:
143	gpio_free(led_dat->gpio);
144	return ret;
145}
146
147static void delete_gpio_led(struct gpio_led_data *led)
148{
149	if (!gpio_is_valid(led->gpio))
150		return;
151	led_classdev_unregister(&led->cdev);
152	cancel_work_sync(&led->work);
153	gpio_free(led->gpio);
154}
155
156struct gpio_leds_priv {
157	int num_leds;
158	struct gpio_led_data leds[];
159};
160
161static inline int sizeof_gpio_leds_priv(int num_leds)
162{
163	return sizeof(struct gpio_leds_priv) +
164		(sizeof(struct gpio_led_data) * num_leds);
165}
166
167/* Code to create from OpenFirmware platform devices */
168#ifdef CONFIG_LEDS_GPIO_OF
169static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
170{
171	struct device_node *np = pdev->dev.of_node, *child;
172	struct gpio_leds_priv *priv;
173	int count = 0, ret;
174
175	/* count LEDs in this device, so we know how much to allocate */
176	for_each_child_of_node(np, child)
177		count++;
178	if (!count)
179		return NULL;
180
181	priv = kzalloc(sizeof_gpio_leds_priv(count), GFP_KERNEL);
182	if (!priv)
183		return NULL;
184
185	for_each_child_of_node(np, child) {
186		struct gpio_led led = {};
187		enum of_gpio_flags flags;
188		const char *state;
189
190		led.gpio = of_get_gpio_flags(child, 0, &flags);
191		led.active_low = flags & OF_GPIO_ACTIVE_LOW;
192		led.name = of_get_property(child, "label", NULL) ? : child->name;
193		led.default_trigger =
194			of_get_property(child, "linux,default-trigger", NULL);
195		state = of_get_property(child, "default-state", NULL);
196		if (state) {
197			if (!strcmp(state, "keep"))
198				led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
199			else if (!strcmp(state, "on"))
200				led.default_state = LEDS_GPIO_DEFSTATE_ON;
201			else
202				led.default_state = LEDS_GPIO_DEFSTATE_OFF;
203		}
204
205		ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
206				      &pdev->dev, NULL);
207		if (ret < 0) {
208			of_node_put(child);
209			goto err;
210		}
211	}
212
213	return priv;
214
215err:
216	for (count = priv->num_leds - 2; count >= 0; count--)
217		delete_gpio_led(&priv->leds[count]);
218	kfree(priv);
219	return NULL;
220}
221
222static const struct of_device_id of_gpio_leds_match[] = {
223	{ .compatible = "gpio-leds", },
224	{},
225};
226#else
227static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
228{
229	return NULL;
230}
231#define of_gpio_leds_match NULL
232#endif
233
234
235static int __devinit gpio_led_probe(struct platform_device *pdev)
236{
237	struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
238	struct gpio_leds_priv *priv;
239	int i, ret = 0;
240
241	if (pdata && pdata->num_leds) {
242		priv = kzalloc(sizeof_gpio_leds_priv(pdata->num_leds),
243				GFP_KERNEL);
244		if (!priv)
245			return -ENOMEM;
246
247		priv->num_leds = pdata->num_leds;
248		for (i = 0; i < priv->num_leds; i++) {
249			ret = create_gpio_led(&pdata->leds[i],
250					      &priv->leds[i],
251					      &pdev->dev, pdata->gpio_blink_set);
252			if (ret < 0) {
253				/* On failure: unwind the led creations */
254				for (i = i - 1; i >= 0; i--)
255					delete_gpio_led(&priv->leds[i]);
256				kfree(priv);
257				return ret;
258			}
259		}
260	} else {
261		priv = gpio_leds_create_of(pdev);
262		if (!priv)
263			return -ENODEV;
264	}
265
266	platform_set_drvdata(pdev, priv);
267
268	return 0;
269}
270
271static int __devexit gpio_led_remove(struct platform_device *pdev)
272{
273	struct gpio_leds_priv *priv = dev_get_drvdata(&pdev->dev);
274	int i;
275
276	for (i = 0; i < priv->num_leds; i++)
277		delete_gpio_led(&priv->leds[i]);
278
279	dev_set_drvdata(&pdev->dev, NULL);
280	kfree(priv);
281
282	return 0;
283}
284
285static struct platform_driver gpio_led_driver = {
286	.probe		= gpio_led_probe,
287	.remove		= __devexit_p(gpio_led_remove),
288	.driver		= {
289		.name	= "leds-gpio",
290		.owner	= THIS_MODULE,
291		.of_match_table = of_gpio_leds_match,
292	},
293};
294
295MODULE_ALIAS("platform:leds-gpio");
296
297static int __init gpio_led_init(void)
298{
299	return platform_driver_register(&gpio_led_driver);
300}
301
302static void __exit gpio_led_exit(void)
303{
304	platform_driver_unregister(&gpio_led_driver);
305}
306
307module_init(gpio_led_init);
308module_exit(gpio_led_exit);
309
310MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
311MODULE_DESCRIPTION("GPIO LED driver");
312MODULE_LICENSE("GPL");