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/platform_device.h>
14#include <linux/leds.h>
15#include <linux/err.h>
16#include <linux/mfd/wm8350/pmic.h>
17#include <linux/regulator/consumer.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20
21/* Microamps */
22static const int isink_cur[] = {
23	4,
24	5,
25	6,
26	7,
27	8,
28	10,
29	11,
30	14,
31	16,
32	19,
33	23,
34	27,
35	32,
36	39,
37	46,
38	54,
39	65,
40	77,
41	92,
42	109,
43	130,
44	154,
45	183,
46	218,
47	259,
48	308,
49	367,
50	436,
51	518,
52	616,
53	733,
54	872,
55	1037,
56	1233,
57	1466,
58	1744,
59	2073,
60	2466,
61	2933,
62	3487,
63	4147,
64	4932,
65	5865,
66	6975,
67	8294,
68	9864,
69	11730,
70	13949,
71	16589,
72	19728,
73	23460,
74	27899,
75	33178,
76	39455,
77	46920,
78	55798,
79	66355,
80	78910,
81	93840,
82	111596,
83	132710,
84	157820,
85	187681,
86	223191
87};
88
89#define to_wm8350_led(led_cdev) \
90	container_of(led_cdev, struct wm8350_led, cdev)
91
92static void wm8350_led_enable(struct wm8350_led *led)
93{
94	int ret;
95
96	if (led->enabled)
97		return;
98
99	ret = regulator_enable(led->isink);
100	if (ret != 0) {
101		dev_err(led->cdev.dev, "Failed to enable ISINK: %d\n", ret);
102		return;
103	}
104
105	ret = regulator_enable(led->dcdc);
106	if (ret != 0) {
107		dev_err(led->cdev.dev, "Failed to enable DCDC: %d\n", ret);
108		regulator_disable(led->isink);
109		return;
110	}
111
112	led->enabled = 1;
113}
114
115static void wm8350_led_disable(struct wm8350_led *led)
116{
117	int ret;
118
119	if (!led->enabled)
120		return;
121
122	ret = regulator_disable(led->dcdc);
123	if (ret != 0) {
124		dev_err(led->cdev.dev, "Failed to disable DCDC: %d\n", ret);
125		return;
126	}
127
128	ret = regulator_disable(led->isink);
129	if (ret != 0) {
130		dev_err(led->cdev.dev, "Failed to disable ISINK: %d\n", ret);
131		ret = regulator_enable(led->dcdc);
132		if (ret != 0)
133			dev_err(led->cdev.dev, "Failed to reenable DCDC: %d\n",
134				ret);
135		return;
136	}
137
138	led->enabled = 0;
139}
140
141static void led_work(struct work_struct *work)
142{
143	struct wm8350_led *led = container_of(work, struct wm8350_led, work);
144	int ret;
145	int uA;
146	unsigned long flags;
147
148	mutex_lock(&led->mutex);
149
150	spin_lock_irqsave(&led->value_lock, flags);
151
152	if (led->value == LED_OFF) {
153		spin_unlock_irqrestore(&led->value_lock, flags);
154		wm8350_led_disable(led);
155		goto out;
156	}
157
158	/* This scales linearly into the index of valid current
159	 * settings which results in a linear scaling of perceived
160	 * brightness due to the non-linear current settings provided
161	 * by the hardware.
162	 */
163	uA = (led->max_uA_index * led->value) / LED_FULL;
164	spin_unlock_irqrestore(&led->value_lock, flags);
165	BUG_ON(uA >= ARRAY_SIZE(isink_cur));
166
167	ret = regulator_set_current_limit(led->isink, isink_cur[uA],
168					  isink_cur[uA]);
169	if (ret != 0)
170		dev_err(led->cdev.dev, "Failed to set %duA: %d\n",
171			isink_cur[uA], ret);
172
173	wm8350_led_enable(led);
174
175out:
176	mutex_unlock(&led->mutex);
177}
178
179static void wm8350_led_set(struct led_classdev *led_cdev,
180			   enum led_brightness value)
181{
182	struct wm8350_led *led = to_wm8350_led(led_cdev);
183	unsigned long flags;
184
185	spin_lock_irqsave(&led->value_lock, flags);
186	led->value = value;
187	schedule_work(&led->work);
188	spin_unlock_irqrestore(&led->value_lock, flags);
189}
190
191static void wm8350_led_shutdown(struct platform_device *pdev)
192{
193	struct wm8350_led *led = platform_get_drvdata(pdev);
194
195	mutex_lock(&led->mutex);
196	led->value = LED_OFF;
197	wm8350_led_disable(led);
198	mutex_unlock(&led->mutex);
199}
200
201static int wm8350_led_probe(struct platform_device *pdev)
202{
203	struct regulator *isink, *dcdc;
204	struct wm8350_led *led;
205	struct wm8350_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
206	int i;
207
208	if (pdata == NULL) {
209		dev_err(&pdev->dev, "no platform data\n");
210		return -ENODEV;
211	}
212
213	if (pdata->max_uA < isink_cur[0]) {
214		dev_err(&pdev->dev, "Invalid maximum current %duA\n",
215			pdata->max_uA);
216		return -EINVAL;
217	}
218
219	isink = devm_regulator_get(&pdev->dev, "led_isink");
220	if (IS_ERR(isink)) {
221		dev_err(&pdev->dev, "%s: can't get ISINK\n", __func__);
222		return PTR_ERR(isink);
223	}
224
225	dcdc = devm_regulator_get(&pdev->dev, "led_vcc");
226	if (IS_ERR(dcdc)) {
227		dev_err(&pdev->dev, "%s: can't get DCDC\n", __func__);
228		return PTR_ERR(dcdc);
229	}
230
231	led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
232	if (led == NULL)
233		return -ENOMEM;
234
235	led->cdev.brightness_set = wm8350_led_set;
236	led->cdev.default_trigger = pdata->default_trigger;
237	led->cdev.name = pdata->name;
238	led->cdev.flags |= LED_CORE_SUSPENDRESUME;
239	led->enabled = regulator_is_enabled(isink);
240	led->isink = isink;
241	led->dcdc = dcdc;
242
243	for (i = 0; i < ARRAY_SIZE(isink_cur) - 1; i++)
244		if (isink_cur[i] >= pdata->max_uA)
245			break;
246	led->max_uA_index = i;
247	if (pdata->max_uA != isink_cur[i])
248		dev_warn(&pdev->dev,
249			 "Maximum current %duA is not directly supported,"
250			 " check platform data\n",
251			 pdata->max_uA);
252
253	spin_lock_init(&led->value_lock);
254	mutex_init(&led->mutex);
255	INIT_WORK(&led->work, led_work);
256	led->value = LED_OFF;
257	platform_set_drvdata(pdev, led);
258
259	return led_classdev_register(&pdev->dev, &led->cdev);
260}
261
262static int wm8350_led_remove(struct platform_device *pdev)
263{
264	struct wm8350_led *led = platform_get_drvdata(pdev);
265
266	led_classdev_unregister(&led->cdev);
267	flush_work(&led->work);
268	wm8350_led_disable(led);
269	return 0;
270}
271
272static struct platform_driver wm8350_led_driver = {
273	.driver = {
274		   .name = "wm8350-led",
275		   },
276	.probe = wm8350_led_probe,
277	.remove = wm8350_led_remove,
278	.shutdown = wm8350_led_shutdown,
279};
280
281module_platform_driver(wm8350_led_driver);
282
283MODULE_AUTHOR("Mark Brown");
284MODULE_DESCRIPTION("WM8350 LED driver");
285MODULE_LICENSE("GPL");
286MODULE_ALIAS("platform:wm8350-led");
287