Root/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/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
26struct 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
38static 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
52static 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
84static 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
95static 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                    (led_dat->active_low ^ state) ?
131                    GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
132                    template->name);
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_child_count(np);
174    if (!count)
175        return ERR_PTR(-ENODEV);
176
177    for_each_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_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        ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
207                      &pdev->dev, NULL);
208        if (ret < 0) {
209            of_node_put(child);
210            goto err;
211        }
212    }
213
214    return priv;
215
216err:
217    for (count = priv->num_leds - 2; count >= 0; count--)
218        delete_gpio_led(&priv->leds[count]);
219    return ERR_PTR(-ENODEV);
220}
221
222static const struct of_device_id of_gpio_leds_match[] = {
223    { .compatible = "gpio-leds", },
224    {},
225};
226#else /* CONFIG_OF_GPIO */
227static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
228{
229    return ERR_PTR(-ENODEV);
230}
231#endif /* CONFIG_OF_GPIO */
232
233
234static int gpio_led_probe(struct platform_device *pdev)
235{
236    struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
237    struct gpio_leds_priv *priv;
238    struct pinctrl *pinctrl;
239    int i, ret = 0;
240
241    pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
242    if (IS_ERR(pinctrl))
243        dev_warn(&pdev->dev,
244            "pins are not configured from the driver\n");
245
246    if (pdata && pdata->num_leds) {
247        priv = devm_kzalloc(&pdev->dev,
248                sizeof_gpio_leds_priv(pdata->num_leds),
249                    GFP_KERNEL);
250        if (!priv)
251            return -ENOMEM;
252
253        priv->num_leds = pdata->num_leds;
254        for (i = 0; i < priv->num_leds; i++) {
255            ret = create_gpio_led(&pdata->leds[i],
256                          &priv->leds[i],
257                          &pdev->dev, pdata->gpio_blink_set);
258            if (ret < 0) {
259                /* On failure: unwind the led creations */
260                for (i = i - 1; i >= 0; i--)
261                    delete_gpio_led(&priv->leds[i]);
262                return ret;
263            }
264        }
265    } else {
266        priv = gpio_leds_create_of(pdev);
267        if (IS_ERR(priv))
268            return PTR_ERR(priv);
269    }
270
271    platform_set_drvdata(pdev, priv);
272
273    return 0;
274}
275
276static int gpio_led_remove(struct platform_device *pdev)
277{
278    struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
279    int i;
280
281    for (i = 0; i < priv->num_leds; i++)
282        delete_gpio_led(&priv->leds[i]);
283
284    platform_set_drvdata(pdev, NULL);
285
286    return 0;
287}
288
289static struct platform_driver gpio_led_driver = {
290    .probe = gpio_led_probe,
291    .remove = gpio_led_remove,
292    .driver = {
293        .name = "leds-gpio",
294        .owner = THIS_MODULE,
295        .of_match_table = of_match_ptr(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

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