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a4f3d55c MB |
1 | /* |
2 | * Backlight driver for Wolfson Microelectronics WM831x PMICs | |
3 | * | |
4 | * Copyright 2009 Wolfson Microelectonics 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 | #include <linux/kernel.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/platform_device.h> | |
355b200b | 14 | #include <linux/module.h> |
a4f3d55c MB |
15 | #include <linux/fb.h> |
16 | #include <linux/backlight.h> | |
5a0e3ad6 | 17 | #include <linux/slab.h> |
a4f3d55c MB |
18 | |
19 | #include <linux/mfd/wm831x/core.h> | |
20 | #include <linux/mfd/wm831x/pdata.h> | |
21 | #include <linux/mfd/wm831x/regulator.h> | |
22 | ||
23 | struct wm831x_backlight_data { | |
24 | struct wm831x *wm831x; | |
25 | int isink_reg; | |
26 | int current_brightness; | |
27 | }; | |
28 | ||
29 | static int wm831x_backlight_set(struct backlight_device *bl, int brightness) | |
30 | { | |
31 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
32 | struct wm831x *wm831x = data->wm831x; | |
33 | int power_up = !data->current_brightness && brightness; | |
34 | int power_down = data->current_brightness && !brightness; | |
35 | int ret; | |
36 | ||
37 | if (power_up) { | |
38 | /* Enable the ISINK */ | |
39 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
40 | WM831X_CS1_ENA, WM831X_CS1_ENA); | |
41 | if (ret < 0) | |
42 | goto err; | |
43 | ||
44 | /* Enable the DC-DC */ | |
45 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, | |
46 | WM831X_DC4_ENA, WM831X_DC4_ENA); | |
47 | if (ret < 0) | |
48 | goto err; | |
49 | } | |
50 | ||
51 | if (power_down) { | |
52 | /* DCDC first */ | |
53 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, | |
54 | WM831X_DC4_ENA, 0); | |
55 | if (ret < 0) | |
56 | goto err; | |
57 | ||
58 | /* ISINK */ | |
59 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
60 | WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); | |
61 | if (ret < 0) | |
62 | goto err; | |
63 | } | |
64 | ||
65 | /* Set the new brightness */ | |
66 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
67 | WM831X_CS1_ISEL_MASK, brightness); | |
68 | if (ret < 0) | |
69 | goto err; | |
70 | ||
71 | if (power_up) { | |
72 | /* Drive current through the ISINK */ | |
73 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
74 | WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); | |
75 | if (ret < 0) | |
76 | return ret; | |
77 | } | |
78 | ||
79 | data->current_brightness = brightness; | |
80 | ||
81 | return 0; | |
82 | ||
83 | err: | |
84 | /* If we were in the middle of a power transition always shut down | |
85 | * for safety. | |
86 | */ | |
87 | if (power_up || power_down) { | |
88 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); | |
89 | wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); | |
90 | } | |
91 | ||
92 | return ret; | |
93 | } | |
94 | ||
95 | static int wm831x_backlight_update_status(struct backlight_device *bl) | |
96 | { | |
97 | int brightness = bl->props.brightness; | |
98 | ||
99 | if (bl->props.power != FB_BLANK_UNBLANK) | |
100 | brightness = 0; | |
101 | ||
102 | if (bl->props.fb_blank != FB_BLANK_UNBLANK) | |
103 | brightness = 0; | |
104 | ||
105 | if (bl->props.state & BL_CORE_SUSPENDED) | |
106 | brightness = 0; | |
107 | ||
108 | return wm831x_backlight_set(bl, brightness); | |
109 | } | |
110 | ||
111 | static int wm831x_backlight_get_brightness(struct backlight_device *bl) | |
112 | { | |
113 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
114 | return data->current_brightness; | |
115 | } | |
116 | ||
9905a43b | 117 | static const struct backlight_ops wm831x_backlight_ops = { |
a4f3d55c MB |
118 | .options = BL_CORE_SUSPENDRESUME, |
119 | .update_status = wm831x_backlight_update_status, | |
120 | .get_brightness = wm831x_backlight_get_brightness, | |
121 | }; | |
122 | ||
123 | static int wm831x_backlight_probe(struct platform_device *pdev) | |
124 | { | |
125 | struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); | |
126 | struct wm831x_pdata *wm831x_pdata; | |
127 | struct wm831x_backlight_pdata *pdata; | |
128 | struct wm831x_backlight_data *data; | |
129 | struct backlight_device *bl; | |
a19a6ee6 | 130 | struct backlight_properties props; |
a4f3d55c MB |
131 | int ret, i, max_isel, isink_reg, dcdc_cfg; |
132 | ||
133 | /* We need platform data */ | |
134 | if (pdev->dev.parent->platform_data) { | |
135 | wm831x_pdata = pdev->dev.parent->platform_data; | |
136 | pdata = wm831x_pdata->backlight; | |
137 | } else { | |
138 | pdata = NULL; | |
139 | } | |
140 | ||
141 | if (!pdata) { | |
142 | dev_err(&pdev->dev, "No platform data supplied\n"); | |
143 | return -EINVAL; | |
144 | } | |
145 | ||
146 | /* Figure out the maximum current we can use */ | |
147 | for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { | |
148 | if (wm831x_isinkv_values[i] > pdata->max_uA) | |
149 | break; | |
150 | } | |
151 | ||
152 | if (i == 0) { | |
153 | dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); | |
154 | return -EINVAL; | |
155 | } | |
156 | max_isel = i - 1; | |
157 | ||
158 | if (pdata->max_uA != wm831x_isinkv_values[max_isel]) | |
159 | dev_warn(&pdev->dev, | |
160 | "Maximum current is %duA not %duA as requested\n", | |
161 | wm831x_isinkv_values[max_isel], pdata->max_uA); | |
162 | ||
163 | switch (pdata->isink) { | |
164 | case 1: | |
165 | isink_reg = WM831X_CURRENT_SINK_1; | |
166 | dcdc_cfg = 0; | |
167 | break; | |
168 | case 2: | |
169 | isink_reg = WM831X_CURRENT_SINK_2; | |
170 | dcdc_cfg = WM831X_DC4_FBSRC; | |
171 | break; | |
172 | default: | |
173 | dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); | |
174 | return -EINVAL; | |
175 | } | |
176 | ||
177 | /* Configure the ISINK to use for feedback */ | |
178 | ret = wm831x_reg_unlock(wm831x); | |
179 | if (ret < 0) | |
180 | return ret; | |
181 | ||
182 | ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, | |
183 | dcdc_cfg); | |
184 | ||
185 | wm831x_reg_lock(wm831x); | |
186 | if (ret < 0) | |
187 | return ret; | |
188 | ||
1107d40a | 189 | data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
a4f3d55c MB |
190 | if (data == NULL) |
191 | return -ENOMEM; | |
192 | ||
193 | data->wm831x = wm831x; | |
194 | data->current_brightness = 0; | |
195 | data->isink_reg = isink_reg; | |
196 | ||
f5f4fd45 | 197 | memset(&props, 0, sizeof(props)); |
bb7ca747 | 198 | props.type = BACKLIGHT_RAW; |
a19a6ee6 MG |
199 | props.max_brightness = max_isel; |
200 | bl = backlight_device_register("wm831x", &pdev->dev, data, | |
201 | &wm831x_backlight_ops, &props); | |
a4f3d55c MB |
202 | if (IS_ERR(bl)) { |
203 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
a4f3d55c MB |
204 | return PTR_ERR(bl); |
205 | } | |
206 | ||
a4f3d55c MB |
207 | bl->props.brightness = max_isel; |
208 | ||
209 | platform_set_drvdata(pdev, bl); | |
210 | ||
211 | /* Disable the DCDC if it was started so we can bootstrap */ | |
212 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); | |
213 | ||
a4f3d55c MB |
214 | backlight_update_status(bl); |
215 | ||
216 | return 0; | |
217 | } | |
218 | ||
219 | static int wm831x_backlight_remove(struct platform_device *pdev) | |
220 | { | |
221 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
a4f3d55c MB |
222 | |
223 | backlight_device_unregister(bl); | |
a4f3d55c MB |
224 | return 0; |
225 | } | |
226 | ||
227 | static struct platform_driver wm831x_backlight_driver = { | |
228 | .driver = { | |
229 | .name = "wm831x-backlight", | |
230 | .owner = THIS_MODULE, | |
231 | }, | |
232 | .probe = wm831x_backlight_probe, | |
233 | .remove = wm831x_backlight_remove, | |
234 | }; | |
235 | ||
81178e02 | 236 | module_platform_driver(wm831x_backlight_driver); |
a4f3d55c MB |
237 | |
238 | MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); | |
239 | MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); | |
240 | MODULE_LICENSE("GPL"); | |
241 | MODULE_ALIAS("platform:wm831x-backlight"); |