xref: /linux/drivers/leds/leds-gpio.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
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_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/pinctrl/consumer.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 	led_dat->cdev.name = template->name;
111 	led_dat->cdev.default_trigger = template->default_trigger;
112 	led_dat->gpio = template->gpio;
113 	led_dat->can_sleep = gpio_cansleep(template->gpio);
114 	led_dat->active_low = template->active_low;
115 	led_dat->blinking = 0;
116 	if (blink_set) {
117 		led_dat->platform_gpio_blink_set = blink_set;
118 		led_dat->cdev.blink_set = gpio_blink_set;
119 	}
120 	led_dat->cdev.brightness_set = gpio_led_set;
121 	if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
122 		state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low;
123 	else
124 		state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
125 	led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
126 	if (!template->retain_state_suspended)
127 		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
128 
129 	ret = devm_gpio_request_one(parent, template->gpio,
130 			GPIOF_DIR_OUT | (led_dat->active_low ^ state),
131 			template->name);
132 	if (ret < 0)
133 		return ret;
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 		return ret;
140 
141 	return 0;
142 }
143 
144 static void delete_gpio_led(struct gpio_led_data *led)
145 {
146 	if (!gpio_is_valid(led->gpio))
147 		return;
148 	led_classdev_unregister(&led->cdev);
149 	cancel_work_sync(&led->work);
150 }
151 
152 struct gpio_leds_priv {
153 	int num_leds;
154 	struct gpio_led_data leds[];
155 };
156 
157 static inline int sizeof_gpio_leds_priv(int num_leds)
158 {
159 	return sizeof(struct gpio_leds_priv) +
160 		(sizeof(struct gpio_led_data) * num_leds);
161 }
162 
163 /* Code to create from OpenFirmware platform devices */
164 #ifdef CONFIG_OF_GPIO
165 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
166 {
167 	struct device_node *np = pdev->dev.of_node, *child;
168 	struct gpio_leds_priv *priv;
169 	int count, ret;
170 
171 	/* count LEDs in this device, so we know how much to allocate */
172 	count = of_get_child_count(np);
173 	if (!count)
174 		return ERR_PTR(-ENODEV);
175 
176 	for_each_child_of_node(np, child)
177 		if (of_get_gpio(child, 0) == -EPROBE_DEFER)
178 			return ERR_PTR(-EPROBE_DEFER);
179 
180 	priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count),
181 			GFP_KERNEL);
182 	if (!priv)
183 		return ERR_PTR(-ENOMEM);
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 
215 err:
216 	for (count = priv->num_leds - 2; count >= 0; count--)
217 		delete_gpio_led(&priv->leds[count]);
218 	return ERR_PTR(-ENODEV);
219 }
220 
221 static const struct of_device_id of_gpio_leds_match[] = {
222 	{ .compatible = "gpio-leds", },
223 	{},
224 };
225 #else /* CONFIG_OF_GPIO */
226 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
227 {
228 	return ERR_PTR(-ENODEV);
229 }
230 #endif /* CONFIG_OF_GPIO */
231 
232 
233 static int gpio_led_probe(struct platform_device *pdev)
234 {
235 	struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
236 	struct gpio_leds_priv *priv;
237 	struct pinctrl *pinctrl;
238 	int i, ret = 0;
239 
240 	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
241 	if (IS_ERR(pinctrl))
242 		dev_warn(&pdev->dev,
243 			"pins are not configured from the driver\n");
244 
245 	if (pdata && pdata->num_leds) {
246 		priv = devm_kzalloc(&pdev->dev,
247 				sizeof_gpio_leds_priv(pdata->num_leds),
248 					GFP_KERNEL);
249 		if (!priv)
250 			return -ENOMEM;
251 
252 		priv->num_leds = pdata->num_leds;
253 		for (i = 0; i < priv->num_leds; i++) {
254 			ret = create_gpio_led(&pdata->leds[i],
255 					      &priv->leds[i],
256 					      &pdev->dev, pdata->gpio_blink_set);
257 			if (ret < 0) {
258 				/* On failure: unwind the led creations */
259 				for (i = i - 1; i >= 0; i--)
260 					delete_gpio_led(&priv->leds[i]);
261 				return ret;
262 			}
263 		}
264 	} else {
265 		priv = gpio_leds_create_of(pdev);
266 		if (IS_ERR(priv))
267 			return PTR_ERR(priv);
268 	}
269 
270 	platform_set_drvdata(pdev, priv);
271 
272 	return 0;
273 }
274 
275 static int gpio_led_remove(struct platform_device *pdev)
276 {
277 	struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
278 	int i;
279 
280 	for (i = 0; i < priv->num_leds; i++)
281 		delete_gpio_led(&priv->leds[i]);
282 
283 	platform_set_drvdata(pdev, NULL);
284 
285 	return 0;
286 }
287 
288 static struct platform_driver gpio_led_driver = {
289 	.probe		= gpio_led_probe,
290 	.remove		= gpio_led_remove,
291 	.driver		= {
292 		.name	= "leds-gpio",
293 		.owner	= THIS_MODULE,
294 		.of_match_table = of_match_ptr(of_gpio_leds_match),
295 	},
296 };
297 
298 module_platform_driver(gpio_led_driver);
299 
300 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
301 MODULE_DESCRIPTION("GPIO LED driver");
302 MODULE_LICENSE("GPL");
303 MODULE_ALIAS("platform:leds-gpio");
304