summaryrefslogtreecommitdiffstats
path: root/drivers/video/backlight/wm831x_bl.c
blob: a4312709fb1bfffe83e83a6152873a8ad65e11b0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
/*
 * Backlight driver for Wolfson Microelectronics WM831x PMICs
 *
 * Copyright 2009 Wolfson Microelectonics plc
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/fb.h>
#include <linux/backlight.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/regulator.h>

struct wm831x_backlight_data {
	struct wm831x *wm831x;
	int isink_reg;
	int current_brightness;
};

static int wm831x_backlight_set(struct backlight_device *bl, int brightness)
{
	struct wm831x_backlight_data *data = bl_get_data(bl);
	struct wm831x *wm831x = data->wm831x;
	int power_up = !data->current_brightness && brightness;
	int power_down = data->current_brightness && !brightness;
	int ret;

	if (power_up) {
		/* Enable the ISINK */
		ret = wm831x_set_bits(wm831x, data->isink_reg,
				      WM831X_CS1_ENA, WM831X_CS1_ENA);
		if (ret < 0)
			goto err;

		/* Enable the DC-DC */
		ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
				      WM831X_DC4_ENA, WM831X_DC4_ENA);
		if (ret < 0)
			goto err;
	}

	if (power_down) {
		/* DCDC first */
		ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
				      WM831X_DC4_ENA, 0);
		if (ret < 0)
			goto err;

		/* ISINK */
		ret = wm831x_set_bits(wm831x, data->isink_reg,
				      WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0);
		if (ret < 0)
			goto err;
	}

	/* Set the new brightness */
	ret = wm831x_set_bits(wm831x, data->isink_reg,
			      WM831X_CS1_ISEL_MASK, brightness);
	if (ret < 0)
		goto err;

	if (power_up) {
		/* Drive current through the ISINK */
		ret = wm831x_set_bits(wm831x, data->isink_reg,
				      WM831X_CS1_DRIVE, WM831X_CS1_DRIVE);
		if (ret < 0)
			return ret;
	}

	data->current_brightness = brightness;

	return 0;

err:
	/* If we were in the middle of a power transition always shut down
	 * for safety.
	 */
	if (power_up || power_down) {
		wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
		wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0);
	}

	return ret;
}

static int wm831x_backlight_update_status(struct backlight_device *bl)
{
	int brightness = bl->props.brightness;

	if (bl->props.power != FB_BLANK_UNBLANK)
		brightness = 0;

	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
		brightness = 0;

	if (bl->props.state & BL_CORE_SUSPENDED)
		brightness = 0;

	return wm831x_backlight_set(bl, brightness);
}

static int wm831x_backlight_get_brightness(struct backlight_device *bl)
{
	struct wm831x_backlight_data *data = bl_get_data(bl);
	return data->current_brightness;
}

static const struct backlight_ops wm831x_backlight_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status	= wm831x_backlight_update_status,
	.get_brightness	= wm831x_backlight_get_brightness,
};

static int wm831x_backlight_probe(struct platform_device *pdev)
{
	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
	struct wm831x_pdata *wm831x_pdata;
	struct wm831x_backlight_pdata *pdata;
	struct wm831x_backlight_data *data;
	struct backlight_device *bl;
	struct backlight_properties props;
	int ret, i, max_isel, isink_reg, dcdc_cfg;

	/* We need platform data */
	if (pdev->dev.parent->platform_data) {
		wm831x_pdata = pdev->dev.parent->platform_data;
		pdata = wm831x_pdata->backlight;
	} else {
		pdata = NULL;
	}

	if (!pdata) {
		dev_err(&pdev->dev, "No platform data supplied\n");
		return -EINVAL;
	}

	/* Figure out the maximum current we can use */
	for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) {
		if (wm831x_isinkv_values[i] > pdata->max_uA)
			break;
	}

	if (i == 0) {
		dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
		return -EINVAL;
	}
	max_isel = i - 1;

	if (pdata->max_uA != wm831x_isinkv_values[max_isel])
		dev_warn(&pdev->dev,
			 "Maximum current is %duA not %duA as requested\n",
			 wm831x_isinkv_values[max_isel], pdata->max_uA);

	switch (pdata->isink) {
	case 1:
		isink_reg = WM831X_CURRENT_SINK_1;
		dcdc_cfg = 0;
		break;
	case 2:
		isink_reg = WM831X_CURRENT_SINK_2;
		dcdc_cfg = WM831X_DC4_FBSRC;
		break;
	default:
		dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
		return -EINVAL;
	}

	/* Configure the ISINK to use for feedback */
	ret = wm831x_reg_unlock(wm831x);
	if (ret < 0)
		return ret;

	ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
			      dcdc_cfg);

	wm831x_reg_lock(wm831x);
	if (ret < 0)
		return ret;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (data == NULL)
		return -ENOMEM;

	data->wm831x = wm831x;
	data->current_brightness = 0;
	data->isink_reg = isink_reg;

	props.max_brightness = max_isel;
	bl = backlight_device_register("wm831x", &pdev->dev, data,
				       &wm831x_backlight_ops, &props);
	if (IS_ERR(bl)) {
		dev_err(&pdev->dev, "failed to register backlight\n");
		kfree(data);
		return PTR_ERR(bl);
	}

	bl->props.brightness = max_isel;

	platform_set_drvdata(pdev, bl);

	/* Disable the DCDC if it was started so we can bootstrap */
	wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);


	backlight_update_status(bl);

	return 0;
}

static int wm831x_backlight_remove(struct platform_device *pdev)
{
	struct backlight_device *bl = platform_get_drvdata(pdev);
	struct wm831x_backlight_data *data = bl_get_data(bl);

	backlight_device_unregister(bl);
	kfree(data);
	return 0;
}

static struct platform_driver wm831x_backlight_driver = {
	.driver		= {
		.name	= "wm831x-backlight",
		.owner	= THIS_MODULE,
	},
	.probe		= wm831x_backlight_probe,
	.remove		= wm831x_backlight_remove,
};

static int __init wm831x_backlight_init(void)
{
	return platform_driver_register(&wm831x_backlight_driver);
}
module_init(wm831x_backlight_init);

static void __exit wm831x_backlight_exit(void)
{
	platform_driver_unregister(&wm831x_backlight_driver);
}
module_exit(wm831x_backlight_exit);

MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-backlight");