[SCSI] libsas: execute transport link resets with libata-eh via host workqueue
[linux-2.6.git] / drivers / leds / leds-regulator.c
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/slab.h>
17 #include <linux/workqueue.h>
18 #include <linux/leds.h>
19 #include <linux/leds-regulator.h>
20 #include <linux/platform_device.h>
21 #include <linux/regulator/consumer.h>
22
23 #define to_regulator_led(led_cdev) \
24         container_of(led_cdev, struct regulator_led, cdev)
25
26 struct regulator_led {
27         struct led_classdev cdev;
28         enum led_brightness value;
29         int enabled;
30         struct mutex mutex;
31         struct work_struct work;
32
33         struct regulator *vcc;
34 };
35
36 static inline int led_regulator_get_max_brightness(struct regulator *supply)
37 {
38         int ret;
39         int voltage = regulator_list_voltage(supply, 0);
40
41         if (voltage <= 0)
42                 return 1;
43
44         /* even if regulator can't change voltages,
45          * we still assume it can change status
46          * and the LED can be turned on and off.
47          */
48         ret = regulator_set_voltage(supply, voltage, voltage);
49         if (ret < 0)
50                 return 1;
51
52         return regulator_count_voltages(supply);
53 }
54
55 static int led_regulator_get_voltage(struct regulator *supply,
56                 enum led_brightness brightness)
57 {
58         if (brightness == 0)
59                 return -EINVAL;
60
61         return regulator_list_voltage(supply, brightness - 1);
62 }
63
64
65 static void regulator_led_enable(struct regulator_led *led)
66 {
67         int ret;
68
69         if (led->enabled)
70                 return;
71
72         ret = regulator_enable(led->vcc);
73         if (ret != 0) {
74                 dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret);
75                 return;
76         }
77
78         led->enabled = 1;
79 }
80
81 static void regulator_led_disable(struct regulator_led *led)
82 {
83         int ret;
84
85         if (!led->enabled)
86                 return;
87
88         ret = regulator_disable(led->vcc);
89         if (ret != 0) {
90                 dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret);
91                 return;
92         }
93
94         led->enabled = 0;
95 }
96
97 static void regulator_led_set_value(struct regulator_led *led)
98 {
99         int voltage;
100         int ret;
101
102         mutex_lock(&led->mutex);
103
104         if (led->value == LED_OFF) {
105                 regulator_led_disable(led);
106                 goto out;
107         }
108
109         if (led->cdev.max_brightness > 1) {
110                 voltage = led_regulator_get_voltage(led->vcc, led->value);
111                 dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n",
112                                 led->value, voltage);
113
114                 ret = regulator_set_voltage(led->vcc, voltage, voltage);
115                 if (ret != 0)
116                         dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n",
117                                 voltage, ret);
118         }
119
120         regulator_led_enable(led);
121
122 out:
123         mutex_unlock(&led->mutex);
124 }
125
126 static void led_work(struct work_struct *work)
127 {
128         struct regulator_led *led;
129
130         led = container_of(work, struct regulator_led, work);
131         regulator_led_set_value(led);
132 }
133
134 static void regulator_led_brightness_set(struct led_classdev *led_cdev,
135                            enum led_brightness value)
136 {
137         struct regulator_led *led = to_regulator_led(led_cdev);
138
139         led->value = value;
140         schedule_work(&led->work);
141 }
142
143 static int __devinit regulator_led_probe(struct platform_device *pdev)
144 {
145         struct led_regulator_platform_data *pdata = pdev->dev.platform_data;
146         struct regulator_led *led;
147         struct regulator *vcc;
148         int ret = 0;
149
150         if (pdata == NULL) {
151                 dev_err(&pdev->dev, "no platform data\n");
152                 return -ENODEV;
153         }
154
155         vcc = regulator_get_exclusive(&pdev->dev, "vled");
156         if (IS_ERR(vcc)) {
157                 dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name);
158                 return PTR_ERR(vcc);
159         }
160
161         led = kzalloc(sizeof(*led), GFP_KERNEL);
162         if (led == NULL) {
163                 ret = -ENOMEM;
164                 goto err_vcc;
165         }
166
167         led->cdev.max_brightness = led_regulator_get_max_brightness(vcc);
168         if (pdata->brightness > led->cdev.max_brightness) {
169                 dev_err(&pdev->dev, "Invalid default brightness %d\n",
170                                 pdata->brightness);
171                 ret = -EINVAL;
172                 goto err_led;
173         }
174         led->value = pdata->brightness;
175
176         led->cdev.brightness_set = regulator_led_brightness_set;
177         led->cdev.name = pdata->name;
178         led->cdev.flags |= LED_CORE_SUSPENDRESUME;
179         led->vcc = vcc;
180
181         /* to handle correctly an already enabled regulator */
182         if (regulator_is_enabled(led->vcc))
183                 led->enabled = 1;
184
185         mutex_init(&led->mutex);
186         INIT_WORK(&led->work, led_work);
187
188         platform_set_drvdata(pdev, led);
189
190         ret = led_classdev_register(&pdev->dev, &led->cdev);
191         if (ret < 0) {
192                 cancel_work_sync(&led->work);
193                 goto err_led;
194         }
195
196         /* to expose the default value to userspace */
197         led->cdev.brightness = led->value;
198
199         /* Set the default led status */
200         regulator_led_set_value(led);
201
202         return 0;
203
204 err_led:
205         kfree(led);
206 err_vcc:
207         regulator_put(vcc);
208         return ret;
209 }
210
211 static int __devexit regulator_led_remove(struct platform_device *pdev)
212 {
213         struct regulator_led *led = platform_get_drvdata(pdev);
214
215         led_classdev_unregister(&led->cdev);
216         cancel_work_sync(&led->work);
217         regulator_led_disable(led);
218         regulator_put(led->vcc);
219         kfree(led);
220         return 0;
221 }
222
223 static struct platform_driver regulator_led_driver = {
224         .driver = {
225                    .name  = "leds-regulator",
226                    .owner = THIS_MODULE,
227                    },
228         .probe  = regulator_led_probe,
229         .remove = __devexit_p(regulator_led_remove),
230 };
231
232 module_platform_driver(regulator_led_driver);
233
234 MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
235 MODULE_DESCRIPTION("Regulator driven LED driver");
236 MODULE_LICENSE("GPL");
237 MODULE_ALIAS("platform:leds-regulator");