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/platform_device.h>
20#include <linux/property.h>
21#include <linux/slab.h>
22#include <linux/workqueue.h>
23
24struct gpio_led_data {
25	struct led_classdev cdev;
26	struct gpio_desc *gpiod;
27	struct work_struct work;
28	u8 new_level;
29	u8 can_sleep;
30	u8 blinking;
31	int (*platform_gpio_blink_set)(struct gpio_desc *desc, int state,
32			unsigned long *delay_on, unsigned long *delay_off);
33};
34
35static void gpio_led_work(struct work_struct *work)
36{
37	struct gpio_led_data *led_dat =
38		container_of(work, struct gpio_led_data, work);
39
40	if (led_dat->blinking) {
41		led_dat->platform_gpio_blink_set(led_dat->gpiod,
42					led_dat->new_level, NULL, NULL);
43		led_dat->blinking = 0;
44	} else
45		gpiod_set_value_cansleep(led_dat->gpiod, led_dat->new_level);
46}
47
48static void gpio_led_set(struct led_classdev *led_cdev,
49	enum led_brightness value)
50{
51	struct gpio_led_data *led_dat =
52		container_of(led_cdev, struct gpio_led_data, cdev);
53	int level;
54
55	if (value == LED_OFF)
56		level = 0;
57	else
58		level = 1;
59
60	/* Setting GPIOs with I2C/etc requires a task context, and we don't
61	 * seem to have a reliable way to know if we're already in one; so
62	 * let's just assume the worst.
63	 */
64	if (led_dat->can_sleep) {
65		led_dat->new_level = level;
66		schedule_work(&led_dat->work);
67	} else {
68		if (led_dat->blinking) {
69			led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
70							 NULL, NULL);
71			led_dat->blinking = 0;
72		} else
73			gpiod_set_value(led_dat->gpiod, level);
74	}
75}
76
77static int gpio_blink_set(struct led_classdev *led_cdev,
78	unsigned long *delay_on, unsigned long *delay_off)
79{
80	struct gpio_led_data *led_dat =
81		container_of(led_cdev, struct gpio_led_data, cdev);
82
83	led_dat->blinking = 1;
84	return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
85						delay_on, delay_off);
86}
87
88static int create_gpio_led(const struct gpio_led *template,
89	struct gpio_led_data *led_dat, struct device *parent,
90	int (*blink_set)(struct gpio_desc *, int, unsigned long *,
91			 unsigned long *))
92{
93	int ret, state;
94
95	led_dat->gpiod = template->gpiod;
96	if (!led_dat->gpiod) {
97		/*
98		 * This is the legacy code path for platform code that
99		 * still uses GPIO numbers. Ultimately we would like to get
100		 * rid of this block completely.
101		 */
102		unsigned long flags = 0;
103
104		/* skip leds that aren't available */
105		if (!gpio_is_valid(template->gpio)) {
106			dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
107					template->gpio, template->name);
108			return 0;
109		}
110
111		if (template->active_low)
112			flags |= GPIOF_ACTIVE_LOW;
113
114		ret = devm_gpio_request_one(parent, template->gpio, flags,
115					    template->name);
116		if (ret < 0)
117			return ret;
118
119		led_dat->gpiod = gpio_to_desc(template->gpio);
120		if (IS_ERR(led_dat->gpiod))
121			return PTR_ERR(led_dat->gpiod);
122	}
123
124	led_dat->cdev.name = template->name;
125	led_dat->cdev.default_trigger = template->default_trigger;
126	led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
127	led_dat->blinking = 0;
128	if (blink_set) {
129		led_dat->platform_gpio_blink_set = blink_set;
130		led_dat->cdev.blink_set = gpio_blink_set;
131	}
132	led_dat->cdev.brightness_set = gpio_led_set;
133	if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
134		state = !!gpiod_get_value_cansleep(led_dat->gpiod);
135	else
136		state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
137	led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
138	if (!template->retain_state_suspended)
139		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
140
141	ret = gpiod_direction_output(led_dat->gpiod, state);
142	if (ret < 0)
143		return ret;
144
145	INIT_WORK(&led_dat->work, gpio_led_work);
146
147	return led_classdev_register(parent, &led_dat->cdev);
148}
149
150static void delete_gpio_led(struct gpio_led_data *led)
151{
152	led_classdev_unregister(&led->cdev);
153	cancel_work_sync(&led->work);
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
167static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
168{
169	struct device *dev = &pdev->dev;
170	struct fwnode_handle *child;
171	struct gpio_leds_priv *priv;
172	int count, ret;
173	struct device_node *np;
174
175	count = device_get_child_node_count(dev);
176	if (!count)
177		return ERR_PTR(-ENODEV);
178
179	priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
180	if (!priv)
181		return ERR_PTR(-ENOMEM);
182
183	device_for_each_child_node(dev, child) {
184		struct gpio_led led = {};
185		const char *state = NULL;
186
187		led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
188		if (IS_ERR(led.gpiod)) {
189			fwnode_handle_put(child);
190			ret = PTR_ERR(led.gpiod);
191			goto err;
192		}
193
194		np = of_node(child);
195
196		if (fwnode_property_present(child, "label")) {
197			fwnode_property_read_string(child, "label", &led.name);
198		} else {
199			if (IS_ENABLED(CONFIG_OF) && !led.name && np)
200				led.name = np->name;
201			if (!led.name)
202				return ERR_PTR(-EINVAL);
203		}
204		fwnode_property_read_string(child, "linux,default-trigger",
205					    &led.default_trigger);
206
207		if (!fwnode_property_read_string(child, "default-state",
208						 &state)) {
209			if (!strcmp(state, "keep"))
210				led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
211			else if (!strcmp(state, "on"))
212				led.default_state = LEDS_GPIO_DEFSTATE_ON;
213			else
214				led.default_state = LEDS_GPIO_DEFSTATE_OFF;
215		}
216
217		if (fwnode_property_present(child, "retain-state-suspended"))
218			led.retain_state_suspended = 1;
219
220		ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
221				      dev, NULL);
222		if (ret < 0) {
223			fwnode_handle_put(child);
224			goto err;
225		}
226	}
227
228	return priv;
229
230err:
231	for (count = priv->num_leds - 2; count >= 0; count--)
232		delete_gpio_led(&priv->leds[count]);
233	return ERR_PTR(ret);
234}
235
236static const struct of_device_id of_gpio_leds_match[] = {
237	{ .compatible = "gpio-leds", },
238	{},
239};
240
241MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
242
243static int gpio_led_probe(struct platform_device *pdev)
244{
245	struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
246	struct gpio_leds_priv *priv;
247	int i, ret = 0;
248
249	if (pdata && pdata->num_leds) {
250		priv = devm_kzalloc(&pdev->dev,
251				sizeof_gpio_leds_priv(pdata->num_leds),
252					GFP_KERNEL);
253		if (!priv)
254			return -ENOMEM;
255
256		priv->num_leds = pdata->num_leds;
257		for (i = 0; i < priv->num_leds; i++) {
258			ret = create_gpio_led(&pdata->leds[i],
259					      &priv->leds[i],
260					      &pdev->dev, pdata->gpio_blink_set);
261			if (ret < 0) {
262				/* On failure: unwind the led creations */
263				for (i = i - 1; i >= 0; i--)
264					delete_gpio_led(&priv->leds[i]);
265				return ret;
266			}
267		}
268	} else {
269		priv = gpio_leds_create(pdev);
270		if (IS_ERR(priv))
271			return PTR_ERR(priv);
272	}
273
274	platform_set_drvdata(pdev, priv);
275
276	return 0;
277}
278
279static int gpio_led_remove(struct platform_device *pdev)
280{
281	struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
282	int i;
283
284	for (i = 0; i < priv->num_leds; i++)
285		delete_gpio_led(&priv->leds[i]);
286
287	return 0;
288}
289
290static struct platform_driver gpio_led_driver = {
291	.probe		= gpio_led_probe,
292	.remove		= gpio_led_remove,
293	.driver		= {
294		.name	= "leds-gpio",
295		.of_match_table = of_gpio_leds_match,
296	},
297};
298
299module_platform_driver(gpio_led_driver);
300
301MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
302MODULE_DESCRIPTION("GPIO LED driver");
303MODULE_LICENSE("GPL");
304MODULE_ALIAS("platform:leds-gpio");
305