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authorMark Brown <broonie@opensource.wolfsonmicro.com>2009-09-05 09:09:20 -0400
committerRichard Purdie <rpurdie@linux.intel.com>2009-09-07 09:05:07 -0400
commita4f3d55cb0b8e1199e352c30ea9a264cef9c1ae1 (patch)
tree8b9fb9b49dde8139f31adf4e81037678c428aa59 /drivers
parente07cccf4046978df10f2e13fe2b99b2f9b3a65db (diff)
backlight: Add WM831x backlight driver
The WM831x series of PMICs provide DC-DC boost convertors and current sinks which can be used together to drive LEDs for use as backlights. Expose this functionality via the backlight API. Since when used in this configuration the current sink and boost convertor are very tightly coupled with a multi-stage startup for the current sink which overlaps with the boost convertor startup this driver bypasses the regulator API. Machine inititialisation is responsible for ensuring that the regulators are not accessed via both APIs. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/video/backlight/Kconfig7
-rw-r--r--drivers/video/backlight/Makefile1
-rw-r--r--drivers/video/backlight/wm831x_bl.c250
3 files changed, 258 insertions, 0 deletions
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index f9d19be05540..f86dbfd209ad 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -229,3 +229,10 @@ config BACKLIGHT_SAHARA
229 help 229 help
230 If you have a Tabletkiosk Sahara Touch-iT, say y to enable the 230 If you have a Tabletkiosk Sahara Touch-iT, say y to enable the
231 backlight driver. 231 backlight driver.
232
233config BACKLIGHT_WM831X
234 tristate "WM831x PMIC Backlight Driver"
235 depends on BACKLIGHT_CLASS_DEVICE && MFD_WM831X
236 help
237 If you have a backlight driven by the ISINK and DCDC of a
238 WM831x PMIC say y to enable the backlight driver for it.
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 4eb178c1d684..df0b67ce88b6 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -24,4 +24,5 @@ obj-$(CONFIG_BACKLIGHT_DA903X) += da903x_bl.o
24obj-$(CONFIG_BACKLIGHT_MBP_NVIDIA) += mbp_nvidia_bl.o 24obj-$(CONFIG_BACKLIGHT_MBP_NVIDIA) += mbp_nvidia_bl.o
25obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o 25obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o
26obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o 26obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o
27obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o
27 28
diff --git a/drivers/video/backlight/wm831x_bl.c b/drivers/video/backlight/wm831x_bl.c
new file mode 100644
index 000000000000..467bdb7efb23
--- /dev/null
+++ b/drivers/video/backlight/wm831x_bl.c
@@ -0,0 +1,250 @@
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
21struct wm831x_backlight_data {
22 struct wm831x *wm831x;
23 int isink_reg;
24 int current_brightness;
25};
26
27static 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
81err:
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
93static 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
109static 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
115static struct backlight_ops wm831x_backlight_ops = {
116 .options = BL_CORE_SUSPENDRESUME,
117 .update_status = wm831x_backlight_update_status,
118 .get_brightness = wm831x_backlight_get_brightness,
119};
120
121static 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;
128 int ret, i, max_isel, isink_reg, dcdc_cfg;
129
130 /* We need platform data */
131 if (pdev->dev.parent->platform_data) {
132 wm831x_pdata = pdev->dev.parent->platform_data;
133 pdata = wm831x_pdata->backlight;
134 } else {
135 pdata = NULL;
136 }
137
138 if (!pdata) {
139 dev_err(&pdev->dev, "No platform data supplied\n");
140 return -EINVAL;
141 }
142
143 /* Figure out the maximum current we can use */
144 for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) {
145 if (wm831x_isinkv_values[i] > pdata->max_uA)
146 break;
147 }
148
149 if (i == 0) {
150 dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
151 return -EINVAL;
152 }
153 max_isel = i - 1;
154
155 if (pdata->max_uA != wm831x_isinkv_values[max_isel])
156 dev_warn(&pdev->dev,
157 "Maximum current is %duA not %duA as requested\n",
158 wm831x_isinkv_values[max_isel], pdata->max_uA);
159
160 switch (pdata->isink) {
161 case 1:
162 isink_reg = WM831X_CURRENT_SINK_1;
163 dcdc_cfg = 0;
164 break;
165 case 2:
166 isink_reg = WM831X_CURRENT_SINK_2;
167 dcdc_cfg = WM831X_DC4_FBSRC;
168 break;
169 default:
170 dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
171 return -EINVAL;
172 }
173
174 /* Configure the ISINK to use for feedback */
175 ret = wm831x_reg_unlock(wm831x);
176 if (ret < 0)
177 return ret;
178
179 ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
180 dcdc_cfg);
181
182 wm831x_reg_lock(wm831x);
183 if (ret < 0)
184 return ret;
185
186 data = kzalloc(sizeof(*data), GFP_KERNEL);
187 if (data == NULL)
188 return -ENOMEM;
189
190 data->wm831x = wm831x;
191 data->current_brightness = 0;
192 data->isink_reg = isink_reg;
193
194 bl = backlight_device_register("wm831x", &pdev->dev,
195 data, &wm831x_backlight_ops);
196 if (IS_ERR(bl)) {
197 dev_err(&pdev->dev, "failed to register backlight\n");
198 kfree(data);
199 return PTR_ERR(bl);
200 }
201
202 bl->props.max_brightness = max_isel;
203 bl->props.brightness = max_isel;
204
205 platform_set_drvdata(pdev, bl);
206
207 /* Disable the DCDC if it was started so we can bootstrap */
208 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
209
210
211 backlight_update_status(bl);
212
213 return 0;
214}
215
216static int wm831x_backlight_remove(struct platform_device *pdev)
217{
218 struct backlight_device *bl = platform_get_drvdata(pdev);
219 struct wm831x_backlight_data *data = bl_get_data(bl);
220
221 backlight_device_unregister(bl);
222 kfree(data);
223 return 0;
224}
225
226static struct platform_driver wm831x_backlight_driver = {
227 .driver = {
228 .name = "wm831x-backlight",
229 .owner = THIS_MODULE,
230 },
231 .probe = wm831x_backlight_probe,
232 .remove = wm831x_backlight_remove,
233};
234
235static int __init wm831x_backlight_init(void)
236{
237 return platform_driver_register(&wm831x_backlight_driver);
238}
239module_init(wm831x_backlight_init);
240
241static void __exit wm831x_backlight_exit(void)
242{
243 platform_driver_unregister(&wm831x_backlight_driver);
244}
245module_exit(wm831x_backlight_exit);
246
247MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
248MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
249MODULE_LICENSE("GPL");
250MODULE_ALIAS("platform:wm831x-backlight");