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d4cc6a2e AO |
1 | /* |
2 | * leds-regulator.c - LED class driver for regulator driven LEDs. | |
3 | * | |
4 | * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it> | |
5 | * | |
6 | * Inspired by leds-wm8350 driver. | |
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/module.h> | |
15 | #include <linux/err.h> | |
16 | #include <linux/workqueue.h> | |
17 | #include <linux/leds.h> | |
18 | #include <linux/leds-regulator.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/regulator/consumer.h> | |
21 | ||
22 | #define to_regulator_led(led_cdev) \ | |
23 | container_of(led_cdev, struct regulator_led, cdev) | |
24 | ||
25 | struct regulator_led { | |
26 | struct led_classdev cdev; | |
27 | enum led_brightness value; | |
28 | int enabled; | |
29 | struct mutex mutex; | |
30 | struct work_struct work; | |
31 | ||
32 | struct regulator *vcc; | |
33 | }; | |
34 | ||
35 | static inline int led_regulator_get_max_brightness(struct regulator *supply) | |
36 | { | |
37 | int ret; | |
38 | int voltage = regulator_list_voltage(supply, 0); | |
39 | ||
40 | if (voltage <= 0) | |
41 | return 1; | |
42 | ||
43 | /* even if regulator can't change voltages, | |
44 | * we still assume it can change status | |
45 | * and the LED can be turned on and off. | |
46 | */ | |
47 | ret = regulator_set_voltage(supply, voltage, voltage); | |
48 | if (ret < 0) | |
49 | return 1; | |
50 | ||
51 | return regulator_count_voltages(supply); | |
52 | } | |
53 | ||
54 | static int led_regulator_get_voltage(struct regulator *supply, | |
55 | enum led_brightness brightness) | |
56 | { | |
57 | if (brightness == 0) | |
58 | return -EINVAL; | |
59 | ||
60 | return regulator_list_voltage(supply, brightness - 1); | |
61 | } | |
62 | ||
63 | ||
64 | static void regulator_led_enable(struct regulator_led *led) | |
65 | { | |
66 | int ret; | |
67 | ||
68 | if (led->enabled) | |
69 | return; | |
70 | ||
71 | ret = regulator_enable(led->vcc); | |
72 | if (ret != 0) { | |
73 | dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret); | |
74 | return; | |
75 | } | |
76 | ||
77 | led->enabled = 1; | |
78 | } | |
79 | ||
80 | static void regulator_led_disable(struct regulator_led *led) | |
81 | { | |
82 | int ret; | |
83 | ||
84 | if (!led->enabled) | |
85 | return; | |
86 | ||
87 | ret = regulator_disable(led->vcc); | |
88 | if (ret != 0) { | |
89 | dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret); | |
90 | return; | |
91 | } | |
92 | ||
93 | led->enabled = 0; | |
94 | } | |
95 | ||
96 | static void regulator_led_set_value(struct regulator_led *led) | |
97 | { | |
98 | int voltage; | |
99 | int ret; | |
100 | ||
101 | mutex_lock(&led->mutex); | |
102 | ||
103 | if (led->value == LED_OFF) { | |
104 | regulator_led_disable(led); | |
105 | goto out; | |
106 | } | |
107 | ||
108 | if (led->cdev.max_brightness > 1) { | |
109 | voltage = led_regulator_get_voltage(led->vcc, led->value); | |
110 | dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n", | |
111 | led->value, voltage); | |
112 | ||
113 | ret = regulator_set_voltage(led->vcc, voltage, voltage); | |
114 | if (ret != 0) | |
115 | dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n", | |
116 | voltage, ret); | |
117 | } | |
118 | ||
119 | regulator_led_enable(led); | |
120 | ||
121 | out: | |
122 | mutex_unlock(&led->mutex); | |
123 | } | |
124 | ||
125 | static void led_work(struct work_struct *work) | |
126 | { | |
127 | struct regulator_led *led; | |
128 | ||
129 | led = container_of(work, struct regulator_led, work); | |
130 | regulator_led_set_value(led); | |
131 | } | |
132 | ||
133 | static void regulator_led_brightness_set(struct led_classdev *led_cdev, | |
134 | enum led_brightness value) | |
135 | { | |
136 | struct regulator_led *led = to_regulator_led(led_cdev); | |
137 | ||
138 | led->value = value; | |
139 | schedule_work(&led->work); | |
140 | } | |
141 | ||
142 | static int __devinit regulator_led_probe(struct platform_device *pdev) | |
143 | { | |
144 | struct led_regulator_platform_data *pdata = pdev->dev.platform_data; | |
145 | struct regulator_led *led; | |
146 | struct regulator *vcc; | |
147 | int ret = 0; | |
148 | ||
149 | if (pdata == NULL) { | |
150 | dev_err(&pdev->dev, "no platform data\n"); | |
151 | return -ENODEV; | |
152 | } | |
153 | ||
154 | vcc = regulator_get_exclusive(&pdev->dev, "vled"); | |
155 | if (IS_ERR(vcc)) { | |
156 | dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name); | |
157 | return PTR_ERR(vcc); | |
158 | } | |
159 | ||
160 | led = kzalloc(sizeof(*led), GFP_KERNEL); | |
161 | if (led == NULL) { | |
162 | ret = -ENOMEM; | |
163 | goto err_vcc; | |
164 | } | |
165 | ||
166 | led->cdev.max_brightness = led_regulator_get_max_brightness(vcc); | |
167 | if (pdata->brightness > led->cdev.max_brightness) { | |
168 | dev_err(&pdev->dev, "Invalid default brightness %d\n", | |
169 | pdata->brightness); | |
170 | ret = -EINVAL; | |
171 | goto err_led; | |
172 | } | |
173 | led->value = pdata->brightness; | |
174 | ||
175 | led->cdev.brightness_set = regulator_led_brightness_set; | |
176 | led->cdev.name = pdata->name; | |
177 | led->cdev.flags |= LED_CORE_SUSPENDRESUME; | |
178 | led->vcc = vcc; | |
179 | ||
180 | mutex_init(&led->mutex); | |
181 | INIT_WORK(&led->work, led_work); | |
182 | ||
183 | platform_set_drvdata(pdev, led); | |
184 | ||
185 | ret = led_classdev_register(&pdev->dev, &led->cdev); | |
186 | if (ret < 0) { | |
187 | cancel_work_sync(&led->work); | |
188 | goto err_led; | |
189 | } | |
190 | ||
191 | /* to expose the default value to userspace */ | |
192 | led->cdev.brightness = led->value; | |
193 | ||
194 | /* Set the default led status */ | |
195 | regulator_led_set_value(led); | |
196 | ||
197 | return 0; | |
198 | ||
199 | err_led: | |
200 | kfree(led); | |
201 | err_vcc: | |
202 | regulator_put(vcc); | |
203 | return ret; | |
204 | } | |
205 | ||
206 | static int __devexit regulator_led_remove(struct platform_device *pdev) | |
207 | { | |
208 | struct regulator_led *led = platform_get_drvdata(pdev); | |
209 | ||
210 | led_classdev_unregister(&led->cdev); | |
211 | cancel_work_sync(&led->work); | |
212 | regulator_led_disable(led); | |
213 | regulator_put(led->vcc); | |
214 | kfree(led); | |
215 | return 0; | |
216 | } | |
217 | ||
218 | static struct platform_driver regulator_led_driver = { | |
219 | .driver = { | |
220 | .name = "leds-regulator", | |
221 | .owner = THIS_MODULE, | |
222 | }, | |
223 | .probe = regulator_led_probe, | |
224 | .remove = __devexit_p(regulator_led_remove), | |
225 | }; | |
226 | ||
227 | static int __init regulator_led_init(void) | |
228 | { | |
229 | return platform_driver_register(®ulator_led_driver); | |
230 | } | |
231 | module_init(regulator_led_init); | |
232 | ||
233 | static void __exit regulator_led_exit(void) | |
234 | { | |
235 | platform_driver_unregister(®ulator_led_driver); | |
236 | } | |
237 | module_exit(regulator_led_exit); | |
238 | ||
239 | MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); | |
240 | MODULE_DESCRIPTION("Regulator driven LED driver"); | |
241 | MODULE_LICENSE("GPL"); | |
242 | MODULE_ALIAS("platform:leds-regulator"); |