xref: /linux/drivers/leds/leds-gpio.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * LEDs driver for GPIOs
4  *
5  * Copyright (C) 2007 8D Technologies inc.
6  * Raphael Assenat <raph@8d.com>
7  * Copyright (C) 2008 Freescale Semiconductor, Inc.
8  */
9 #include <linux/container_of.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/gpio.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/leds.h>
15 #include <linux/mod_devicetable.h>
16 #include <linux/module.h>
17 #include <linux/overflow.h>
18 #include <linux/pinctrl/consumer.h>
19 #include <linux/platform_device.h>
20 #include <linux/property.h>
21 #include <linux/slab.h>
22 #include <linux/types.h>
23 
24 #include "leds.h"
25 
26 struct gpio_led_data {
27 	struct led_classdev cdev;
28 	struct gpio_desc *gpiod;
29 	u8 can_sleep;
30 	u8 blinking;
31 	gpio_blink_set_t platform_gpio_blink_set;
32 };
33 
34 static inline struct gpio_led_data *
35 			cdev_to_gpio_led_data(struct led_classdev *led_cdev)
36 {
37 	return container_of(led_cdev, struct gpio_led_data, cdev);
38 }
39 
40 static void gpio_led_set(struct led_classdev *led_cdev,
41 	enum led_brightness value)
42 {
43 	struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
44 	int level;
45 
46 	if (value == LED_OFF)
47 		level = 0;
48 	else
49 		level = 1;
50 
51 	if (led_dat->blinking) {
52 		led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
53 						 NULL, NULL);
54 		led_dat->blinking = 0;
55 	} else {
56 		if (led_dat->can_sleep)
57 			gpiod_set_value_cansleep(led_dat->gpiod, level);
58 		else
59 			gpiod_set_value(led_dat->gpiod, level);
60 	}
61 }
62 
63 static int gpio_led_set_blocking(struct led_classdev *led_cdev,
64 	enum led_brightness value)
65 {
66 	gpio_led_set(led_cdev, value);
67 	return 0;
68 }
69 
70 static int gpio_blink_set(struct led_classdev *led_cdev,
71 	unsigned long *delay_on, unsigned long *delay_off)
72 {
73 	struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
74 
75 	led_dat->blinking = 1;
76 	return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
77 						delay_on, delay_off);
78 }
79 
80 static int create_gpio_led(const struct gpio_led *template,
81 	struct gpio_led_data *led_dat, struct device *parent,
82 	struct fwnode_handle *fwnode, gpio_blink_set_t blink_set)
83 {
84 	struct led_init_data init_data = {};
85 	struct pinctrl *pinctrl;
86 	int ret, state;
87 
88 	led_dat->cdev.default_trigger = template->default_trigger;
89 	led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
90 	if (!led_dat->can_sleep)
91 		led_dat->cdev.brightness_set = gpio_led_set;
92 	else
93 		led_dat->cdev.brightness_set_blocking = gpio_led_set_blocking;
94 	led_dat->blinking = 0;
95 	if (blink_set) {
96 		led_dat->platform_gpio_blink_set = blink_set;
97 		led_dat->cdev.blink_set = gpio_blink_set;
98 	}
99 	if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) {
100 		state = gpiod_get_value_cansleep(led_dat->gpiod);
101 		if (state < 0)
102 			return state;
103 	} else {
104 		state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
105 	}
106 	led_dat->cdev.brightness = state;
107 	led_dat->cdev.max_brightness = 1;
108 	if (!template->retain_state_suspended)
109 		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
110 	if (template->panic_indicator)
111 		led_dat->cdev.flags |= LED_PANIC_INDICATOR;
112 	if (template->retain_state_shutdown)
113 		led_dat->cdev.flags |= LED_RETAIN_AT_SHUTDOWN;
114 
115 	ret = gpiod_direction_output(led_dat->gpiod, state);
116 	if (ret < 0)
117 		return ret;
118 
119 	if (template->name) {
120 		led_dat->cdev.name = template->name;
121 		ret = devm_led_classdev_register(parent, &led_dat->cdev);
122 	} else {
123 		init_data.fwnode = fwnode;
124 		ret = devm_led_classdev_register_ext(parent, &led_dat->cdev,
125 						     &init_data);
126 	}
127 
128 	if (ret)
129 		return ret;
130 
131 	pinctrl = devm_pinctrl_get_select_default(led_dat->cdev.dev);
132 	ret = PTR_ERR_OR_ZERO(pinctrl);
133 	/* pinctrl-%d not present, not an error */
134 	if (ret == -ENODEV)
135 		ret = 0;
136 	if (ret) {
137 		dev_warn(led_dat->cdev.dev, "Failed to select %pfw pinctrl: %d\n",
138 			 fwnode, ret);
139 	}
140 
141 	return ret;
142 }
143 
144 struct gpio_leds_priv {
145 	int num_leds;
146 	struct gpio_led_data leds[] __counted_by(num_leds);
147 };
148 
149 static struct gpio_leds_priv *gpio_leds_create(struct device *dev)
150 {
151 	struct fwnode_handle *child;
152 	struct gpio_leds_priv *priv;
153 	int count, used, ret;
154 
155 	count = device_get_child_node_count(dev);
156 	if (!count)
157 		return ERR_PTR(-ENODEV);
158 
159 	priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
160 	if (!priv)
161 		return ERR_PTR(-ENOMEM);
162 	priv->num_leds = count;
163 	used = 0;
164 
165 	device_for_each_child_node(dev, child) {
166 		struct gpio_led_data *led_dat = &priv->leds[used];
167 		struct gpio_led led = {};
168 
169 		/*
170 		 * Acquire gpiod from DT with uninitialized label, which
171 		 * will be updated after LED class device is registered,
172 		 * Only then the final LED name is known.
173 		 */
174 		led.gpiod = devm_fwnode_gpiod_get(dev, child, NULL, GPIOD_ASIS,
175 						  NULL);
176 		if (IS_ERR(led.gpiod)) {
177 			dev_err_probe(dev, PTR_ERR(led.gpiod), "Failed to get GPIO '%pfw'\n",
178 				      child);
179 			fwnode_handle_put(child);
180 			return ERR_CAST(led.gpiod);
181 		}
182 
183 		led_dat->gpiod = led.gpiod;
184 
185 		led.default_state = led_init_default_state_get(child);
186 
187 		if (fwnode_property_present(child, "retain-state-suspended"))
188 			led.retain_state_suspended = 1;
189 		if (fwnode_property_present(child, "retain-state-shutdown"))
190 			led.retain_state_shutdown = 1;
191 		if (fwnode_property_present(child, "panic-indicator"))
192 			led.panic_indicator = 1;
193 
194 		ret = create_gpio_led(&led, led_dat, dev, child, NULL);
195 		if (ret < 0) {
196 			fwnode_handle_put(child);
197 			return ERR_PTR(ret);
198 		}
199 		/* Set gpiod label to match the corresponding LED name. */
200 		gpiod_set_consumer_name(led_dat->gpiod,
201 					led_dat->cdev.dev->kobj.name);
202 		used++;
203 	}
204 	priv->num_leds = used;
205 
206 	return priv;
207 }
208 
209 static const struct of_device_id of_gpio_leds_match[] = {
210 	{ .compatible = "gpio-leds", },
211 	{},
212 };
213 
214 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
215 
216 static struct gpio_desc *gpio_led_get_gpiod(struct device *dev, int idx,
217 					    const struct gpio_led *template)
218 {
219 	struct gpio_desc *gpiod;
220 	unsigned long flags = GPIOF_OUT_INIT_LOW;
221 	int ret;
222 
223 	/*
224 	 * This means the LED does not come from the device tree
225 	 * or ACPI, so let's try just getting it by index from the
226 	 * device, this will hit the board file, if any and get
227 	 * the GPIO from there.
228 	 */
229 	gpiod = devm_gpiod_get_index_optional(dev, NULL, idx, GPIOD_OUT_LOW);
230 	if (IS_ERR(gpiod))
231 		return gpiod;
232 	if (gpiod) {
233 		gpiod_set_consumer_name(gpiod, template->name);
234 		return gpiod;
235 	}
236 
237 	/*
238 	 * This is the legacy code path for platform code that
239 	 * still uses GPIO numbers. Ultimately we would like to get
240 	 * rid of this block completely.
241 	 */
242 
243 	/* skip leds that aren't available */
244 	if (!gpio_is_valid(template->gpio))
245 		return ERR_PTR(-ENOENT);
246 
247 	if (template->active_low)
248 		flags |= GPIOF_ACTIVE_LOW;
249 
250 	ret = devm_gpio_request_one(dev, template->gpio, flags,
251 				    template->name);
252 	if (ret < 0)
253 		return ERR_PTR(ret);
254 
255 	gpiod = gpio_to_desc(template->gpio);
256 	if (!gpiod)
257 		return ERR_PTR(-EINVAL);
258 
259 	return gpiod;
260 }
261 
262 static int gpio_led_probe(struct platform_device *pdev)
263 {
264 	struct device *dev = &pdev->dev;
265 	struct gpio_led_platform_data *pdata = dev_get_platdata(dev);
266 	struct gpio_leds_priv *priv;
267 	int i, ret;
268 
269 	if (pdata && pdata->num_leds) {
270 		priv = devm_kzalloc(dev, struct_size(priv, leds, pdata->num_leds), GFP_KERNEL);
271 		if (!priv)
272 			return -ENOMEM;
273 
274 		priv->num_leds = pdata->num_leds;
275 		for (i = 0; i < priv->num_leds; i++) {
276 			const struct gpio_led *template = &pdata->leds[i];
277 			struct gpio_led_data *led_dat = &priv->leds[i];
278 
279 			if (template->gpiod)
280 				led_dat->gpiod = template->gpiod;
281 			else
282 				led_dat->gpiod =
283 					gpio_led_get_gpiod(dev, i, template);
284 			if (IS_ERR(led_dat->gpiod)) {
285 				dev_info(dev, "Skipping unavailable LED gpio %d (%s)\n",
286 					 template->gpio, template->name);
287 				continue;
288 			}
289 
290 			ret = create_gpio_led(template, led_dat, dev, NULL,
291 					      pdata->gpio_blink_set);
292 			if (ret < 0)
293 				return ret;
294 		}
295 	} else {
296 		priv = gpio_leds_create(dev);
297 		if (IS_ERR(priv))
298 			return PTR_ERR(priv);
299 	}
300 
301 	platform_set_drvdata(pdev, priv);
302 
303 	return 0;
304 }
305 
306 static void gpio_led_shutdown(struct platform_device *pdev)
307 {
308 	struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
309 	int i;
310 
311 	for (i = 0; i < priv->num_leds; i++) {
312 		struct gpio_led_data *led = &priv->leds[i];
313 
314 		if (!(led->cdev.flags & LED_RETAIN_AT_SHUTDOWN))
315 			gpio_led_set(&led->cdev, LED_OFF);
316 	}
317 }
318 
319 static struct platform_driver gpio_led_driver = {
320 	.probe		= gpio_led_probe,
321 	.shutdown	= gpio_led_shutdown,
322 	.driver		= {
323 		.name	= "leds-gpio",
324 		.of_match_table = of_gpio_leds_match,
325 	},
326 };
327 
328 module_platform_driver(gpio_led_driver);
329 
330 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
331 MODULE_DESCRIPTION("GPIO LED driver");
332 MODULE_LICENSE("GPL");
333 MODULE_ALIAS("platform:leds-gpio");
334