1 /*
2 * LED Class Core
3 *
4 * Copyright 2005-2006 Openedhand Ltd.
5 *
6 * Author: Richard Purdie <rpurdie@openedhand.com>
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
14 #include <linux/kernel.h>
15 #include <linux/leds.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/rwsem.h>
20 #include "leds.h"
21
22 DECLARE_RWSEM(leds_list_lock);
23 EXPORT_SYMBOL_GPL(leds_list_lock);
24
25 LIST_HEAD(leds_list);
26 EXPORT_SYMBOL_GPL(leds_list);
27
__led_set_brightness(struct led_classdev * led_cdev,enum led_brightness value)28 static int __led_set_brightness(struct led_classdev *led_cdev,
29 enum led_brightness value)
30 {
31 if (!led_cdev->brightness_set)
32 return -ENOTSUPP;
33
34 led_cdev->brightness_set(led_cdev, value);
35
36 return 0;
37 }
38
__led_set_brightness_blocking(struct led_classdev * led_cdev,enum led_brightness value)39 static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
40 enum led_brightness value)
41 {
42 if (!led_cdev->brightness_set_blocking)
43 return -ENOTSUPP;
44
45 return led_cdev->brightness_set_blocking(led_cdev, value);
46 }
47
led_timer_function(unsigned long data)48 static void led_timer_function(unsigned long data)
49 {
50 struct led_classdev *led_cdev = (void *)data;
51 unsigned long brightness;
52 unsigned long delay;
53
54 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
55 led_set_brightness_nosleep(led_cdev, LED_OFF);
56 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
57 return;
58 }
59
60 if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
61 &led_cdev->work_flags)) {
62 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
63 return;
64 }
65
66 brightness = led_get_brightness(led_cdev);
67 if (!brightness) {
68 /* Time to switch the LED on. */
69 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
70 &led_cdev->work_flags))
71 brightness = led_cdev->new_blink_brightness;
72 else
73 brightness = led_cdev->blink_brightness;
74 delay = led_cdev->blink_delay_on;
75 } else {
76 /* Store the current brightness value to be able
77 * to restore it when the delay_off period is over.
78 */
79 led_cdev->blink_brightness = brightness;
80 brightness = LED_OFF;
81 delay = led_cdev->blink_delay_off;
82 }
83
84 led_set_brightness_nosleep(led_cdev, brightness);
85
86 /* Return in next iteration if led is in one-shot mode and we are in
87 * the final blink state so that the led is toggled each delay_on +
88 * delay_off milliseconds in worst case.
89 */
90 if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
91 if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
92 if (brightness)
93 set_bit(LED_BLINK_ONESHOT_STOP,
94 &led_cdev->work_flags);
95 } else {
96 if (!brightness)
97 set_bit(LED_BLINK_ONESHOT_STOP,
98 &led_cdev->work_flags);
99 }
100 }
101
102 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
103 }
104
set_brightness_delayed(struct work_struct * ws)105 static void set_brightness_delayed(struct work_struct *ws)
106 {
107 struct led_classdev *led_cdev =
108 container_of(ws, struct led_classdev, set_brightness_work);
109 int ret = 0;
110
111 if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
112 led_cdev->delayed_set_value = LED_OFF;
113 led_stop_software_blink(led_cdev);
114 }
115
116 ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
117 if (ret == -ENOTSUPP)
118 ret = __led_set_brightness_blocking(led_cdev,
119 led_cdev->delayed_set_value);
120 if (ret < 0 &&
121 /* LED HW might have been unplugged, therefore don't warn */
122 !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
123 (led_cdev->flags & LED_HW_PLUGGABLE)))
124 dev_err(led_cdev->dev,
125 "Setting an LED's brightness failed (%d)\n", ret);
126 }
127
led_set_software_blink(struct led_classdev * led_cdev,unsigned long delay_on,unsigned long delay_off)128 static void led_set_software_blink(struct led_classdev *led_cdev,
129 unsigned long delay_on,
130 unsigned long delay_off)
131 {
132 int current_brightness;
133
134 current_brightness = led_get_brightness(led_cdev);
135 if (current_brightness)
136 led_cdev->blink_brightness = current_brightness;
137 if (!led_cdev->blink_brightness)
138 led_cdev->blink_brightness = led_cdev->max_brightness;
139
140 led_cdev->blink_delay_on = delay_on;
141 led_cdev->blink_delay_off = delay_off;
142
143 /* never on - just set to off */
144 if (!delay_on) {
145 led_set_brightness_nosleep(led_cdev, LED_OFF);
146 return;
147 }
148
149 /* never off - just set to brightness */
150 if (!delay_off) {
151 led_set_brightness_nosleep(led_cdev,
152 led_cdev->blink_brightness);
153 return;
154 }
155
156 set_bit(LED_BLINK_SW, &led_cdev->work_flags);
157 mod_timer(&led_cdev->blink_timer, jiffies + 1);
158 }
159
160
led_blink_setup(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)161 static void led_blink_setup(struct led_classdev *led_cdev,
162 unsigned long *delay_on,
163 unsigned long *delay_off)
164 {
165 if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
166 led_cdev->blink_set &&
167 !led_cdev->blink_set(led_cdev, delay_on, delay_off))
168 return;
169
170 /* blink with 1 Hz as default if nothing specified */
171 if (!*delay_on && !*delay_off)
172 *delay_on = *delay_off = 500;
173
174 led_set_software_blink(led_cdev, *delay_on, *delay_off);
175 }
176
led_init_core(struct led_classdev * led_cdev)177 void led_init_core(struct led_classdev *led_cdev)
178 {
179 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
180
181 setup_timer(&led_cdev->blink_timer, led_timer_function,
182 (unsigned long)led_cdev);
183 }
184 EXPORT_SYMBOL_GPL(led_init_core);
185
led_blink_set(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)186 void led_blink_set(struct led_classdev *led_cdev,
187 unsigned long *delay_on,
188 unsigned long *delay_off)
189 {
190 del_timer_sync(&led_cdev->blink_timer);
191
192 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
193 clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
194 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
195
196 led_blink_setup(led_cdev, delay_on, delay_off);
197 }
198 EXPORT_SYMBOL_GPL(led_blink_set);
199
led_blink_set_oneshot(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off,int invert)200 void led_blink_set_oneshot(struct led_classdev *led_cdev,
201 unsigned long *delay_on,
202 unsigned long *delay_off,
203 int invert)
204 {
205 if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
206 timer_pending(&led_cdev->blink_timer))
207 return;
208
209 set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
210 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
211
212 if (invert)
213 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
214 else
215 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
216
217 led_blink_setup(led_cdev, delay_on, delay_off);
218 }
219 EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
220
led_stop_software_blink(struct led_classdev * led_cdev)221 void led_stop_software_blink(struct led_classdev *led_cdev)
222 {
223 del_timer_sync(&led_cdev->blink_timer);
224 led_cdev->blink_delay_on = 0;
225 led_cdev->blink_delay_off = 0;
226 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
227 }
228 EXPORT_SYMBOL_GPL(led_stop_software_blink);
229
led_set_brightness(struct led_classdev * led_cdev,enum led_brightness brightness)230 void led_set_brightness(struct led_classdev *led_cdev,
231 enum led_brightness brightness)
232 {
233 /*
234 * If software blink is active, delay brightness setting
235 * until the next timer tick.
236 */
237 if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
238 /*
239 * If we need to disable soft blinking delegate this to the
240 * work queue task to avoid problems in case we are called
241 * from hard irq context.
242 */
243 if (brightness == LED_OFF) {
244 set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
245 schedule_work(&led_cdev->set_brightness_work);
246 } else {
247 set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
248 &led_cdev->work_flags);
249 led_cdev->new_blink_brightness = brightness;
250 }
251 return;
252 }
253
254 led_set_brightness_nosleep(led_cdev, brightness);
255 }
256 EXPORT_SYMBOL_GPL(led_set_brightness);
257
led_set_brightness_nopm(struct led_classdev * led_cdev,enum led_brightness value)258 void led_set_brightness_nopm(struct led_classdev *led_cdev,
259 enum led_brightness value)
260 {
261 /* Use brightness_set op if available, it is guaranteed not to sleep */
262 if (!__led_set_brightness(led_cdev, value))
263 return;
264
265 /* If brightness setting can sleep, delegate it to a work queue task */
266 led_cdev->delayed_set_value = value;
267 schedule_work(&led_cdev->set_brightness_work);
268 }
269 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
270
led_set_brightness_nosleep(struct led_classdev * led_cdev,enum led_brightness value)271 void led_set_brightness_nosleep(struct led_classdev *led_cdev,
272 enum led_brightness value)
273 {
274 led_cdev->brightness = min(value, led_cdev->max_brightness);
275
276 if (led_cdev->flags & LED_SUSPENDED)
277 return;
278
279 led_set_brightness_nopm(led_cdev, led_cdev->brightness);
280 }
281 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
282
led_set_brightness_sync(struct led_classdev * led_cdev,enum led_brightness value)283 int led_set_brightness_sync(struct led_classdev *led_cdev,
284 enum led_brightness value)
285 {
286 if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
287 return -EBUSY;
288
289 led_cdev->brightness = min(value, led_cdev->max_brightness);
290
291 if (led_cdev->flags & LED_SUSPENDED)
292 return 0;
293
294 return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
295 }
296 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
297
led_update_brightness(struct led_classdev * led_cdev)298 int led_update_brightness(struct led_classdev *led_cdev)
299 {
300 int ret = 0;
301
302 if (led_cdev->brightness_get) {
303 ret = led_cdev->brightness_get(led_cdev);
304 if (ret >= 0) {
305 led_cdev->brightness = ret;
306 return 0;
307 }
308 }
309
310 return ret;
311 }
312 EXPORT_SYMBOL_GPL(led_update_brightness);
313
314 /* Caller must ensure led_cdev->led_access held */
led_sysfs_disable(struct led_classdev * led_cdev)315 void led_sysfs_disable(struct led_classdev *led_cdev)
316 {
317 lockdep_assert_held(&led_cdev->led_access);
318
319 led_cdev->flags |= LED_SYSFS_DISABLE;
320 }
321 EXPORT_SYMBOL_GPL(led_sysfs_disable);
322
323 /* Caller must ensure led_cdev->led_access held */
led_sysfs_enable(struct led_classdev * led_cdev)324 void led_sysfs_enable(struct led_classdev *led_cdev)
325 {
326 lockdep_assert_held(&led_cdev->led_access);
327
328 led_cdev->flags &= ~LED_SYSFS_DISABLE;
329 }
330 EXPORT_SYMBOL_GPL(led_sysfs_enable);
331