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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> | |
5a0e3ad6 | 16 | #include <linux/slab.h> |
a4f3d55c MB |
17 | |
18 | #include <linux/mfd/wm831x/core.h> | |
19 | #include <linux/mfd/wm831x/pdata.h> | |
20 | #include <linux/mfd/wm831x/regulator.h> | |
21 | ||
22 | struct wm831x_backlight_data { | |
23 | struct wm831x *wm831x; | |
24 | int isink_reg; | |
25 | int current_brightness; | |
26 | }; | |
27 | ||
28 | static int wm831x_backlight_set(struct backlight_device *bl, int brightness) | |
29 | { | |
30 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
31 | struct wm831x *wm831x = data->wm831x; | |
32 | int power_up = !data->current_brightness && brightness; | |
33 | int power_down = data->current_brightness && !brightness; | |
34 | int ret; | |
35 | ||
36 | if (power_up) { | |
37 | /* Enable the ISINK */ | |
38 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
39 | WM831X_CS1_ENA, WM831X_CS1_ENA); | |
40 | if (ret < 0) | |
41 | goto err; | |
42 | ||
43 | /* Enable the DC-DC */ | |
44 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, | |
45 | WM831X_DC4_ENA, WM831X_DC4_ENA); | |
46 | if (ret < 0) | |
47 | goto err; | |
48 | } | |
49 | ||
50 | if (power_down) { | |
51 | /* DCDC first */ | |
52 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, | |
53 | WM831X_DC4_ENA, 0); | |
54 | if (ret < 0) | |
55 | goto err; | |
56 | ||
57 | /* ISINK */ | |
58 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
59 | WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); | |
60 | if (ret < 0) | |
61 | goto err; | |
62 | } | |
63 | ||
64 | /* Set the new brightness */ | |
65 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
66 | WM831X_CS1_ISEL_MASK, brightness); | |
67 | if (ret < 0) | |
68 | goto err; | |
69 | ||
70 | if (power_up) { | |
71 | /* Drive current through the ISINK */ | |
72 | ret = wm831x_set_bits(wm831x, data->isink_reg, | |
73 | WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); | |
74 | if (ret < 0) | |
75 | return ret; | |
76 | } | |
77 | ||
78 | data->current_brightness = brightness; | |
79 | ||
80 | return 0; | |
81 | ||
82 | err: | |
83 | /* If we were in the middle of a power transition always shut down | |
84 | * for safety. | |
85 | */ | |
86 | if (power_up || power_down) { | |
87 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); | |
88 | wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); | |
89 | } | |
90 | ||
91 | return ret; | |
92 | } | |
93 | ||
94 | static int wm831x_backlight_update_status(struct backlight_device *bl) | |
95 | { | |
96 | int brightness = bl->props.brightness; | |
97 | ||
98 | if (bl->props.power != FB_BLANK_UNBLANK) | |
99 | brightness = 0; | |
100 | ||
101 | if (bl->props.fb_blank != FB_BLANK_UNBLANK) | |
102 | brightness = 0; | |
103 | ||
104 | if (bl->props.state & BL_CORE_SUSPENDED) | |
105 | brightness = 0; | |
106 | ||
107 | return wm831x_backlight_set(bl, brightness); | |
108 | } | |
109 | ||
110 | static int wm831x_backlight_get_brightness(struct backlight_device *bl) | |
111 | { | |
112 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
113 | return data->current_brightness; | |
114 | } | |
115 | ||
9905a43b | 116 | static const struct backlight_ops wm831x_backlight_ops = { |
a4f3d55c MB |
117 | .options = BL_CORE_SUSPENDRESUME, |
118 | .update_status = wm831x_backlight_update_status, | |
119 | .get_brightness = wm831x_backlight_get_brightness, | |
120 | }; | |
121 | ||
122 | static int wm831x_backlight_probe(struct platform_device *pdev) | |
123 | { | |
124 | struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); | |
125 | struct wm831x_pdata *wm831x_pdata; | |
126 | struct wm831x_backlight_pdata *pdata; | |
127 | struct wm831x_backlight_data *data; | |
128 | struct backlight_device *bl; | |
a19a6ee6 | 129 | struct backlight_properties props; |
a4f3d55c MB |
130 | int ret, i, max_isel, isink_reg, dcdc_cfg; |
131 | ||
132 | /* We need platform data */ | |
133 | if (pdev->dev.parent->platform_data) { | |
134 | wm831x_pdata = pdev->dev.parent->platform_data; | |
135 | pdata = wm831x_pdata->backlight; | |
136 | } else { | |
137 | pdata = NULL; | |
138 | } | |
139 | ||
140 | if (!pdata) { | |
141 | dev_err(&pdev->dev, "No platform data supplied\n"); | |
142 | return -EINVAL; | |
143 | } | |
144 | ||
145 | /* Figure out the maximum current we can use */ | |
146 | for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { | |
147 | if (wm831x_isinkv_values[i] > pdata->max_uA) | |
148 | break; | |
149 | } | |
150 | ||
151 | if (i == 0) { | |
152 | dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); | |
153 | return -EINVAL; | |
154 | } | |
155 | max_isel = i - 1; | |
156 | ||
157 | if (pdata->max_uA != wm831x_isinkv_values[max_isel]) | |
158 | dev_warn(&pdev->dev, | |
159 | "Maximum current is %duA not %duA as requested\n", | |
160 | wm831x_isinkv_values[max_isel], pdata->max_uA); | |
161 | ||
162 | switch (pdata->isink) { | |
163 | case 1: | |
164 | isink_reg = WM831X_CURRENT_SINK_1; | |
165 | dcdc_cfg = 0; | |
166 | break; | |
167 | case 2: | |
168 | isink_reg = WM831X_CURRENT_SINK_2; | |
169 | dcdc_cfg = WM831X_DC4_FBSRC; | |
170 | break; | |
171 | default: | |
172 | dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); | |
173 | return -EINVAL; | |
174 | } | |
175 | ||
176 | /* Configure the ISINK to use for feedback */ | |
177 | ret = wm831x_reg_unlock(wm831x); | |
178 | if (ret < 0) | |
179 | return ret; | |
180 | ||
181 | ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, | |
182 | dcdc_cfg); | |
183 | ||
184 | wm831x_reg_lock(wm831x); | |
185 | if (ret < 0) | |
186 | return ret; | |
187 | ||
188 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
189 | if (data == NULL) | |
190 | return -ENOMEM; | |
191 | ||
192 | data->wm831x = wm831x; | |
193 | data->current_brightness = 0; | |
194 | data->isink_reg = isink_reg; | |
195 | ||
a19a6ee6 MG |
196 | props.max_brightness = max_isel; |
197 | bl = backlight_device_register("wm831x", &pdev->dev, data, | |
198 | &wm831x_backlight_ops, &props); | |
a4f3d55c MB |
199 | if (IS_ERR(bl)) { |
200 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
201 | kfree(data); | |
202 | return PTR_ERR(bl); | |
203 | } | |
204 | ||
a4f3d55c MB |
205 | bl->props.brightness = max_isel; |
206 | ||
207 | platform_set_drvdata(pdev, bl); | |
208 | ||
209 | /* Disable the DCDC if it was started so we can bootstrap */ | |
210 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); | |
211 | ||
212 | ||
213 | backlight_update_status(bl); | |
214 | ||
215 | return 0; | |
216 | } | |
217 | ||
218 | static int wm831x_backlight_remove(struct platform_device *pdev) | |
219 | { | |
220 | struct backlight_device *bl = platform_get_drvdata(pdev); | |
221 | struct wm831x_backlight_data *data = bl_get_data(bl); | |
222 | ||
223 | backlight_device_unregister(bl); | |
224 | kfree(data); | |
225 | return 0; | |
226 | } | |
227 | ||
228 | static struct platform_driver wm831x_backlight_driver = { | |
229 | .driver = { | |
230 | .name = "wm831x-backlight", | |
231 | .owner = THIS_MODULE, | |
232 | }, | |
233 | .probe = wm831x_backlight_probe, | |
234 | .remove = wm831x_backlight_remove, | |
235 | }; | |
236 | ||
237 | static int __init wm831x_backlight_init(void) | |
238 | { | |
239 | return platform_driver_register(&wm831x_backlight_driver); | |
240 | } | |
241 | module_init(wm831x_backlight_init); | |
242 | ||
243 | static void __exit wm831x_backlight_exit(void) | |
244 | { | |
245 | platform_driver_unregister(&wm831x_backlight_driver); | |
246 | } | |
247 | module_exit(wm831x_backlight_exit); | |
248 | ||
249 | MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); | |
250 | MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); | |
251 | MODULE_LICENSE("GPL"); | |
252 | MODULE_ALIAS("platform:wm831x-backlight"); |