Root/drivers/leds/leds-wm8350.c

1/*
2 * LED driver for WM8350 driven LEDS.
3 *
4 * Copyright(C) 2007, 2008 Wolfson Microelectronics PLC.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/platform_device.h>
15#include <linux/leds.h>
16#include <linux/err.h>
17#include <linux/mfd/wm8350/pmic.h>
18#include <linux/regulator/consumer.h>
19#include <linux/slab.h>
20#include <linux/module.h>
21
22/* Microamps */
23static const int isink_cur[] = {
24    4,
25    5,
26    6,
27    7,
28    8,
29    10,
30    11,
31    14,
32    16,
33    19,
34    23,
35    27,
36    32,
37    39,
38    46,
39    54,
40    65,
41    77,
42    92,
43    109,
44    130,
45    154,
46    183,
47    218,
48    259,
49    308,
50    367,
51    436,
52    518,
53    616,
54    733,
55    872,
56    1037,
57    1233,
58    1466,
59    1744,
60    2073,
61    2466,
62    2933,
63    3487,
64    4147,
65    4932,
66    5865,
67    6975,
68    8294,
69    9864,
70    11730,
71    13949,
72    16589,
73    19728,
74    23460,
75    27899,
76    33178,
77    39455,
78    46920,
79    55798,
80    66355,
81    78910,
82    93840,
83    111596,
84    132710,
85    157820,
86    187681,
87    223191
88};
89
90#define to_wm8350_led(led_cdev) \
91    container_of(led_cdev, struct wm8350_led, cdev)
92
93static void wm8350_led_enable(struct wm8350_led *led)
94{
95    int ret;
96
97    if (led->enabled)
98        return;
99
100    ret = regulator_enable(led->isink);
101    if (ret != 0) {
102        dev_err(led->cdev.dev, "Failed to enable ISINK: %d\n", ret);
103        return;
104    }
105
106    ret = regulator_enable(led->dcdc);
107    if (ret != 0) {
108        dev_err(led->cdev.dev, "Failed to enable DCDC: %d\n", ret);
109        regulator_disable(led->isink);
110        return;
111    }
112
113    led->enabled = 1;
114}
115
116static void wm8350_led_disable(struct wm8350_led *led)
117{
118    int ret;
119
120    if (!led->enabled)
121        return;
122
123    ret = regulator_disable(led->dcdc);
124    if (ret != 0) {
125        dev_err(led->cdev.dev, "Failed to disable DCDC: %d\n", ret);
126        return;
127    }
128
129    ret = regulator_disable(led->isink);
130    if (ret != 0) {
131        dev_err(led->cdev.dev, "Failed to disable ISINK: %d\n", ret);
132        regulator_enable(led->dcdc);
133        return;
134    }
135
136    led->enabled = 0;
137}
138
139static void led_work(struct work_struct *work)
140{
141    struct wm8350_led *led = container_of(work, struct wm8350_led, work);
142    int ret;
143    int uA;
144    unsigned long flags;
145
146    mutex_lock(&led->mutex);
147
148    spin_lock_irqsave(&led->value_lock, flags);
149
150    if (led->value == LED_OFF) {
151        spin_unlock_irqrestore(&led->value_lock, flags);
152        wm8350_led_disable(led);
153        goto out;
154    }
155
156    /* This scales linearly into the index of valid current
157     * settings which results in a linear scaling of perceived
158     * brightness due to the non-linear current settings provided
159     * by the hardware.
160     */
161    uA = (led->max_uA_index * led->value) / LED_FULL;
162    spin_unlock_irqrestore(&led->value_lock, flags);
163    BUG_ON(uA >= ARRAY_SIZE(isink_cur));
164
165    ret = regulator_set_current_limit(led->isink, isink_cur[uA],
166                      isink_cur[uA]);
167    if (ret != 0)
168        dev_err(led->cdev.dev, "Failed to set %duA: %d\n",
169            isink_cur[uA], ret);
170
171    wm8350_led_enable(led);
172
173out:
174    mutex_unlock(&led->mutex);
175}
176
177static void wm8350_led_set(struct led_classdev *led_cdev,
178               enum led_brightness value)
179{
180    struct wm8350_led *led = to_wm8350_led(led_cdev);
181    unsigned long flags;
182
183    spin_lock_irqsave(&led->value_lock, flags);
184    led->value = value;
185    schedule_work(&led->work);
186    spin_unlock_irqrestore(&led->value_lock, flags);
187}
188
189static void wm8350_led_shutdown(struct platform_device *pdev)
190{
191    struct wm8350_led *led = platform_get_drvdata(pdev);
192
193    mutex_lock(&led->mutex);
194    led->value = LED_OFF;
195    wm8350_led_disable(led);
196    mutex_unlock(&led->mutex);
197}
198
199static int wm8350_led_probe(struct platform_device *pdev)
200{
201    struct regulator *isink, *dcdc;
202    struct wm8350_led *led;
203    struct wm8350_led_platform_data *pdata = pdev->dev.platform_data;
204    int i;
205
206    if (pdata == NULL) {
207        dev_err(&pdev->dev, "no platform data\n");
208        return -ENODEV;
209    }
210
211    if (pdata->max_uA < isink_cur[0]) {
212        dev_err(&pdev->dev, "Invalid maximum current %duA\n",
213            pdata->max_uA);
214        return -EINVAL;
215    }
216
217    isink = devm_regulator_get(&pdev->dev, "led_isink");
218    if (IS_ERR(isink)) {
219        dev_err(&pdev->dev, "%s: can't get ISINK\n", __func__);
220        return PTR_ERR(isink);
221    }
222
223    dcdc = devm_regulator_get(&pdev->dev, "led_vcc");
224    if (IS_ERR(dcdc)) {
225        dev_err(&pdev->dev, "%s: can't get DCDC\n", __func__);
226        return PTR_ERR(dcdc);
227    }
228
229    led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
230    if (led == NULL)
231        return -ENOMEM;
232
233    led->cdev.brightness_set = wm8350_led_set;
234    led->cdev.default_trigger = pdata->default_trigger;
235    led->cdev.name = pdata->name;
236    led->cdev.flags |= LED_CORE_SUSPENDRESUME;
237    led->enabled = regulator_is_enabled(isink);
238    led->isink = isink;
239    led->dcdc = dcdc;
240
241    for (i = 0; i < ARRAY_SIZE(isink_cur) - 1; i++)
242        if (isink_cur[i] >= pdata->max_uA)
243            break;
244    led->max_uA_index = i;
245    if (pdata->max_uA != isink_cur[i])
246        dev_warn(&pdev->dev,
247             "Maximum current %duA is not directly supported,"
248             " check platform data\n",
249             pdata->max_uA);
250
251    spin_lock_init(&led->value_lock);
252    mutex_init(&led->mutex);
253    INIT_WORK(&led->work, led_work);
254    led->value = LED_OFF;
255    platform_set_drvdata(pdev, led);
256
257    return led_classdev_register(&pdev->dev, &led->cdev);
258}
259
260static int wm8350_led_remove(struct platform_device *pdev)
261{
262    struct wm8350_led *led = platform_get_drvdata(pdev);
263
264    led_classdev_unregister(&led->cdev);
265    flush_work(&led->work);
266    wm8350_led_disable(led);
267    return 0;
268}
269
270static struct platform_driver wm8350_led_driver = {
271    .driver = {
272           .name = "wm8350-led",
273           .owner = THIS_MODULE,
274           },
275    .probe = wm8350_led_probe,
276    .remove = wm8350_led_remove,
277    .shutdown = wm8350_led_shutdown,
278};
279
280module_platform_driver(wm8350_led_driver);
281
282MODULE_AUTHOR("Mark Brown");
283MODULE_DESCRIPTION("WM8350 LED driver");
284MODULE_LICENSE("GPL");
285MODULE_ALIAS("platform:wm8350-led");
286

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