[go: nahoru, domu]
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/kernel.h>
16#include <linux/leds.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/of_gpio.h>
20#include <linux/of_platform.h>
21#include <linux/platform_device.h>
22#include <linux/slab.h>
23#include <linux/workqueue.h>
24
25struct 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
37static 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
51static 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
83static 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
94static 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
145static 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
153struct gpio_leds_priv {
154	int num_leds;
155	struct gpio_led_data leds[];
156};
157
158static 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
166static 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
219err:
220	for (count = priv->num_leds - 2; count >= 0; count--)
221		delete_gpio_led(&priv->leds[count]);
222	return ERR_PTR(-ENODEV);
223}
224
225static const struct of_device_id of_gpio_leds_match[] = {
226	{ .compatible = "gpio-leds", },
227	{},
228};
229
230MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
231#else /* CONFIG_OF_GPIO */
232static 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
238static int gpio_led_probe(struct platform_device *pdev)
239{
240	struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
241	struct gpio_leds_priv *priv;
242	int i, ret = 0;
243
244	if (pdata && pdata->num_leds) {
245		priv = devm_kzalloc(&pdev->dev,
246				sizeof_gpio_leds_priv(pdata->num_leds),
247					GFP_KERNEL);
248		if (!priv)
249			return -ENOMEM;
250
251		priv->num_leds = pdata->num_leds;
252		for (i = 0; i < priv->num_leds; i++) {
253			ret = create_gpio_led(&pdata->leds[i],
254					      &priv->leds[i],
255					      &pdev->dev, pdata->gpio_blink_set);
256			if (ret < 0) {
257				/* On failure: unwind the led creations */
258				for (i = i - 1; i >= 0; i--)
259					delete_gpio_led(&priv->leds[i]);
260				return ret;
261			}
262		}
263	} else {
264		priv = gpio_leds_create_of(pdev);
265		if (IS_ERR(priv))
266			return PTR_ERR(priv);
267	}
268
269	platform_set_drvdata(pdev, priv);
270
271	return 0;
272}
273
274static int gpio_led_remove(struct platform_device *pdev)
275{
276	struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
277	int i;
278
279	for (i = 0; i < priv->num_leds; i++)
280		delete_gpio_led(&priv->leds[i]);
281
282	return 0;
283}
284
285static struct platform_driver gpio_led_driver = {
286	.probe		= gpio_led_probe,
287	.remove		= gpio_led_remove,
288	.driver		= {
289		.name	= "leds-gpio",
290		.owner	= THIS_MODULE,
291		.of_match_table = of_match_ptr(of_gpio_leds_match),
292	},
293};
294
295module_platform_driver(gpio_led_driver);
296
297MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
298MODULE_DESCRIPTION("GPIO LED driver");
299MODULE_LICENSE("GPL");
300MODULE_ALIAS("platform:leds-gpio");
301