1/*
2 * Backlight driver for Dialog Semiconductor DA9030/DA9034
3 *
4 * Copyright (C) 2008 Compulab, Ltd.
5 *	Mike Rapoport <mike@compulab.co.il>
6 *
7 * Copyright (C) 2006-2008 Marvell International Ltd.
8 *	Eric Miao <eric.miao@marvell.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15#include <linux/kernel.h>
16#include <linux/init.h>
17#include <linux/platform_device.h>
18#include <linux/fb.h>
19#include <linux/backlight.h>
20#include <linux/mfd/da903x.h>
21#include <linux/slab.h>
22#include <linux/module.h>
23
24#define DA9030_WLED_CONTROL	0x25
25#define DA9030_WLED_CP_EN	(1 << 6)
26#define DA9030_WLED_TRIM(x)	((x) & 0x7)
27
28#define DA9034_WLED_CONTROL1	0x3C
29#define DA9034_WLED_CONTROL2	0x3D
30#define DA9034_WLED_ISET(x)	((x) & 0x1f)
31
32#define DA9034_WLED_BOOST_EN	(1 << 5)
33
34#define DA9030_MAX_BRIGHTNESS	7
35#define DA9034_MAX_BRIGHTNESS	0x7f
36
37struct da903x_backlight_data {
38	struct device *da903x_dev;
39	int id;
40	int current_brightness;
41};
42
43static int da903x_backlight_set(struct backlight_device *bl, int brightness)
44{
45	struct da903x_backlight_data *data = bl_get_data(bl);
46	struct device *dev = data->da903x_dev;
47	uint8_t val;
48	int ret = 0;
49
50	switch (data->id) {
51	case DA9034_ID_WLED:
52		ret = da903x_update(dev, DA9034_WLED_CONTROL1,
53				brightness, 0x7f);
54		if (ret)
55			return ret;
56
57		if (data->current_brightness && brightness == 0)
58			ret = da903x_clr_bits(dev,
59					DA9034_WLED_CONTROL2,
60					DA9034_WLED_BOOST_EN);
61
62		if (data->current_brightness == 0 && brightness)
63			ret = da903x_set_bits(dev,
64					DA9034_WLED_CONTROL2,
65					DA9034_WLED_BOOST_EN);
66		break;
67	case DA9030_ID_WLED:
68		val = DA9030_WLED_TRIM(brightness);
69		val |= brightness ? DA9030_WLED_CP_EN : 0;
70		ret = da903x_write(dev, DA9030_WLED_CONTROL, val);
71		break;
72	}
73
74	if (ret)
75		return ret;
76
77	data->current_brightness = brightness;
78	return 0;
79}
80
81static int da903x_backlight_update_status(struct backlight_device *bl)
82{
83	int brightness = bl->props.brightness;
84
85	if (bl->props.power != FB_BLANK_UNBLANK)
86		brightness = 0;
87
88	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
89		brightness = 0;
90
91	if (bl->props.state & BL_CORE_SUSPENDED)
92		brightness = 0;
93
94	return da903x_backlight_set(bl, brightness);
95}
96
97static int da903x_backlight_get_brightness(struct backlight_device *bl)
98{
99	struct da903x_backlight_data *data = bl_get_data(bl);
100
101	return data->current_brightness;
102}
103
104static const struct backlight_ops da903x_backlight_ops = {
105	.options	= BL_CORE_SUSPENDRESUME,
106	.update_status	= da903x_backlight_update_status,
107	.get_brightness	= da903x_backlight_get_brightness,
108};
109
110static int da903x_backlight_probe(struct platform_device *pdev)
111{
112	struct da9034_backlight_pdata *pdata = dev_get_platdata(&pdev->dev);
113	struct da903x_backlight_data *data;
114	struct backlight_device *bl;
115	struct backlight_properties props;
116	int max_brightness;
117
118	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
119	if (data == NULL)
120		return -ENOMEM;
121
122	switch (pdev->id) {
123	case DA9030_ID_WLED:
124		max_brightness = DA9030_MAX_BRIGHTNESS;
125		break;
126	case DA9034_ID_WLED:
127		max_brightness = DA9034_MAX_BRIGHTNESS;
128		break;
129	default:
130		dev_err(&pdev->dev, "invalid backlight device ID(%d)\n",
131				pdev->id);
132		return -EINVAL;
133	}
134
135	data->id = pdev->id;
136	data->da903x_dev = pdev->dev.parent;
137	data->current_brightness = 0;
138
139	/* adjust the WLED output current */
140	if (pdata)
141		da903x_write(data->da903x_dev, DA9034_WLED_CONTROL2,
142				DA9034_WLED_ISET(pdata->output_current));
143
144	memset(&props, 0, sizeof(props));
145	props.type = BACKLIGHT_RAW;
146	props.max_brightness = max_brightness;
147	bl = devm_backlight_device_register(&pdev->dev, pdev->name,
148					data->da903x_dev, data,
149					&da903x_backlight_ops, &props);
150	if (IS_ERR(bl)) {
151		dev_err(&pdev->dev, "failed to register backlight\n");
152		return PTR_ERR(bl);
153	}
154
155	bl->props.brightness = max_brightness;
156
157	platform_set_drvdata(pdev, bl);
158	backlight_update_status(bl);
159	return 0;
160}
161
162static struct platform_driver da903x_backlight_driver = {
163	.driver		= {
164		.name	= "da903x-backlight",
165	},
166	.probe		= da903x_backlight_probe,
167};
168
169module_platform_driver(da903x_backlight_driver);
170
171MODULE_DESCRIPTION("Backlight Driver for Dialog Semiconductor DA9030/DA9034");
172MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
173MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
174MODULE_LICENSE("GPL");
175MODULE_ALIAS("platform:da903x-backlight");
176