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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> | |
14 | #include <linux/fb.h> | |
15 | #include <linux/backlight.h> | |
16 | ||
17 | #include <linux/mfd/wm831x/core.h> | |
18 | #include <linux/mfd/wm831x/pdata.h> | |
19 | #include <linux/mfd/wm831x/regulator.h> | |
20 | ||
21 | struct wm831x_backlight_data { | |
22 | struct wm831x *wm831x; | |
23 | int isink_reg; | |
24 | int current_brightness; | |
25 | }; | |
26 | ||
27 | static int wm831x_backlight_set(struct backlight_device *bl, int brightness) | |
28 | { | |
29 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
30 | struct wm831x *wm831x = data->wm831x; | |
31 | int power_up = !data->current_brightness && brightness; | |
32 | int power_down = data->current_brightness && !brightness; | |
33 | int ret; | |
34 | ||
35 | if (power_up) { | |
36 | /* Enable the ISINK */ | |
37 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
38 | WM831X_CS1_ENA, WM831X_CS1_ENA); | |
39 | if (ret < 0) | |
40 | goto err; | |
41 | ||
42 | /* Enable the DC-DC */ | |
43 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, | |
44 | WM831X_DC4_ENA, WM831X_DC4_ENA); | |
45 | if (ret < 0) | |
46 | goto err; | |
47 | } | |
48 | ||
49 | if (power_down) { | |
50 | /* DCDC first */ | |
51 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, | |
52 | WM831X_DC4_ENA, 0); | |
53 | if (ret < 0) | |
54 | goto err; | |
55 | ||
56 | /* ISINK */ | |
57 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
58 | WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); | |
59 | if (ret < 0) | |
60 | goto err; | |
61 | } | |
62 | ||
63 | /* Set the new brightness */ | |
64 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
65 | WM831X_CS1_ISEL_MASK, brightness); | |
66 | if (ret < 0) | |
67 | goto err; | |
68 | ||
69 | if (power_up) { | |
70 | /* Drive current through the ISINK */ | |
71 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
72 | WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); | |
73 | if (ret < 0) | |
74 | return ret; | |
75 | } | |
76 | ||
77 | data->current_brightness = brightness; | |
78 | ||
79 | return 0; | |
80 | ||
81 | err: | |
82 | /* If we were in the middle of a power transition always shut down | |
83 | * for safety. | |
84 | */ | |
85 | if (power_up || power_down) { | |
86 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); | |
87 | wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); | |
88 | } | |
89 | ||
90 | return ret; | |
91 | } | |
92 | ||
93 | static int wm831x_backlight_update_status(struct backlight_device *bl) | |
94 | { | |
95 | int brightness = bl->props.brightness; | |
96 | ||
97 | if (bl->props.power != FB_BLANK_UNBLANK) | |
98 | brightness = 0; | |
99 | ||
100 | if (bl->props.fb_blank != FB_BLANK_UNBLANK) | |
101 | brightness = 0; | |
102 | ||
103 | if (bl->props.state & BL_CORE_SUSPENDED) | |
104 | brightness = 0; | |
105 | ||
106 | return wm831x_backlight_set(bl, brightness); | |
107 | } | |
108 | ||
109 | static int wm831x_backlight_get_brightness(struct backlight_device *bl) | |
110 | { | |
111 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
112 | return data->current_brightness; | |
113 | } | |
114 | ||
9905a43b | 115 | static const struct backlight_ops wm831x_backlight_ops = { |
a4f3d55c MB |
116 | .options = BL_CORE_SUSPENDRESUME, |
117 | .update_status = wm831x_backlight_update_status, | |
118 | .get_brightness = wm831x_backlight_get_brightness, | |
119 | }; | |
120 | ||
121 | static int wm831x_backlight_probe(struct platform_device *pdev) | |
122 | { | |
123 | struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); | |
124 | struct wm831x_pdata *wm831x_pdata; | |
125 | struct wm831x_backlight_pdata *pdata; | |
126 | struct wm831x_backlight_data *data; | |
127 | struct backlight_device *bl; | |
a19a6ee6 | 128 | struct backlight_properties props; |
a4f3d55c MB |
129 | int ret, i, max_isel, isink_reg, dcdc_cfg; |
130 | ||
131 | /* We need platform data */ | |
132 | if (pdev->dev.parent->platform_data) { | |
133 | wm831x_pdata = pdev->dev.parent->platform_data; | |
134 | pdata = wm831x_pdata->backlight; | |
135 | } else { | |
136 | pdata = NULL; | |
137 | } | |
138 | ||
139 | if (!pdata) { | |
140 | dev_err(&pdev->dev, "No platform data supplied\n"); | |
141 | return -EINVAL; | |
142 | } | |
143 | ||
144 | /* Figure out the maximum current we can use */ | |
145 | for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { | |
146 | if (wm831x_isinkv_values[i] > pdata->max_uA) | |
147 | break; | |
148 | } | |
149 | ||
150 | if (i == 0) { | |
151 | dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); | |
152 | return -EINVAL; | |
153 | } | |
154 | max_isel = i - 1; | |
155 | ||
156 | if (pdata->max_uA != wm831x_isinkv_values[max_isel]) | |
157 | dev_warn(&pdev->dev, | |
158 | "Maximum current is %duA not %duA as requested\n", | |
159 | wm831x_isinkv_values[max_isel], pdata->max_uA); | |
160 | ||
161 | switch (pdata->isink) { | |
162 | case 1: | |
163 | isink_reg = WM831X_CURRENT_SINK_1; | |
164 | dcdc_cfg = 0; | |
165 | break; | |
166 | case 2: | |
167 | isink_reg = WM831X_CURRENT_SINK_2; | |
168 | dcdc_cfg = WM831X_DC4_FBSRC; | |
169 | break; | |
170 | default: | |
171 | dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); | |
172 | return -EINVAL; | |
173 | } | |
174 | ||
175 | /* Configure the ISINK to use for feedback */ | |
176 | ret = wm831x_reg_unlock(wm831x); | |
177 | if (ret < 0) | |
178 | return ret; | |
179 | ||
180 | ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, | |
181 | dcdc_cfg); | |
182 | ||
183 | wm831x_reg_lock(wm831x); | |
184 | if (ret < 0) | |
185 | return ret; | |
186 | ||
187 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
188 | if (data == NULL) | |
189 | return -ENOMEM; | |
190 | ||
191 | data->wm831x = wm831x; | |
192 | data->current_brightness = 0; | |
193 | data->isink_reg = isink_reg; | |
194 | ||
a19a6ee6 MG |
195 | props.max_brightness = max_isel; |
196 | bl = backlight_device_register("wm831x", &pdev->dev, data, | |
197 | &wm831x_backlight_ops, &props); | |
a4f3d55c MB |
198 | if (IS_ERR(bl)) { |
199 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
200 | kfree(data); | |
201 | return PTR_ERR(bl); | |
202 | } | |
203 | ||
a4f3d55c MB |
204 | bl->props.brightness = max_isel; |
205 | ||
206 | platform_set_drvdata(pdev, bl); | |
207 | ||
208 | /* Disable the DCDC if it was started so we can bootstrap */ | |
209 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); | |
210 | ||
211 | ||
212 | backlight_update_status(bl); | |
213 | ||
214 | return 0; | |
215 | } | |
216 | ||
217 | static int wm831x_backlight_remove(struct platform_device *pdev) | |
218 | { | |
219 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
220 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
221 | ||
222 | backlight_device_unregister(bl); | |
223 | kfree(data); | |
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 | ||
236 | static int __init wm831x_backlight_init(void) | |
237 | { | |
238 | return platform_driver_register(&wm831x_backlight_driver); | |
239 | } | |
240 | module_init(wm831x_backlight_init); | |
241 | ||
242 | static void __exit wm831x_backlight_exit(void) | |
243 | { | |
244 | platform_driver_unregister(&wm831x_backlight_driver); | |
245 | } | |
246 | module_exit(wm831x_backlight_exit); | |
247 | ||
248 | MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); | |
249 | MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); | |
250 | MODULE_LICENSE("GPL"); | |
251 | MODULE_ALIAS("platform:wm831x-backlight"); |