2 * Backlight driver for Wolfson Microelectronics WM831x PMICs
4 * Copyright 2009 Wolfson Microelectonics plc
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.
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/platform_device.h>
15 #include <linux/backlight.h>
16 #include <linux/slab.h>
18 #include <linux/mfd/wm831x/core.h>
19 #include <linux/mfd/wm831x/pdata.h>
20 #include <linux/mfd/wm831x/regulator.h>
22 struct wm831x_backlight_data {
23 struct wm831x *wm831x;
25 int current_brightness;
28 static int wm831x_backlight_set(struct backlight_device *bl, int brightness)
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;
37 /* Enable the ISINK */
38 ret = wm831x_set_bits(wm831x, data->isink_reg,
39 WM831X_CS1_ENA, WM831X_CS1_ENA);
43 /* Enable the DC-DC */
44 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
45 WM831X_DC4_ENA, WM831X_DC4_ENA);
52 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
58 ret = wm831x_set_bits(wm831x, data->isink_reg,
59 WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0);
64 /* Set the new brightness */
65 ret = wm831x_set_bits(wm831x, data->isink_reg,
66 WM831X_CS1_ISEL_MASK, brightness);
71 /* Drive current through the ISINK */
72 ret = wm831x_set_bits(wm831x, data->isink_reg,
73 WM831X_CS1_DRIVE, WM831X_CS1_DRIVE);
78 data->current_brightness = brightness;
83 /* If we were in the middle of a power transition always shut down
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);
94 static int wm831x_backlight_update_status(struct backlight_device *bl)
96 int brightness = bl->props.brightness;
98 if (bl->props.power != FB_BLANK_UNBLANK)
101 if (bl->props.fb_blank != FB_BLANK_UNBLANK)
104 if (bl->props.state & BL_CORE_SUSPENDED)
107 return wm831x_backlight_set(bl, brightness);
110 static int wm831x_backlight_get_brightness(struct backlight_device *bl)
112 struct wm831x_backlight_data *data = bl_get_data(bl);
113 return data->current_brightness;
116 static const struct backlight_ops wm831x_backlight_ops = {
117 .options = BL_CORE_SUSPENDRESUME,
118 .update_status = wm831x_backlight_update_status,
119 .get_brightness = wm831x_backlight_get_brightness,
122 static int wm831x_backlight_probe(struct platform_device *pdev)
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;
129 struct backlight_properties props;
130 int ret, i, max_isel, isink_reg, dcdc_cfg;
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;
141 dev_err(&pdev->dev, "No platform data supplied\n");
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)
152 dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
157 if (pdata->max_uA != wm831x_isinkv_values[max_isel])
159 "Maximum current is %duA not %duA as requested\n",
160 wm831x_isinkv_values[max_isel], pdata->max_uA);
162 switch (pdata->isink) {
164 isink_reg = WM831X_CURRENT_SINK_1;
168 isink_reg = WM831X_CURRENT_SINK_2;
169 dcdc_cfg = WM831X_DC4_FBSRC;
172 dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
176 /* Configure the ISINK to use for feedback */
177 ret = wm831x_reg_unlock(wm831x);
181 ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
184 wm831x_reg_lock(wm831x);
188 data = kzalloc(sizeof(*data), GFP_KERNEL);
192 data->wm831x = wm831x;
193 data->current_brightness = 0;
194 data->isink_reg = isink_reg;
196 props.type = BACKLIGHT_RAW;
197 props.max_brightness = max_isel;
198 bl = backlight_device_register("wm831x", &pdev->dev, data,
199 &wm831x_backlight_ops, &props);
201 dev_err(&pdev->dev, "failed to register backlight\n");
206 bl->props.brightness = max_isel;
208 platform_set_drvdata(pdev, bl);
210 /* Disable the DCDC if it was started so we can bootstrap */
211 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
214 backlight_update_status(bl);
219 static int wm831x_backlight_remove(struct platform_device *pdev)
221 struct backlight_device *bl = platform_get_drvdata(pdev);
222 struct wm831x_backlight_data *data = bl_get_data(bl);
224 backlight_device_unregister(bl);
229 static struct platform_driver wm831x_backlight_driver = {
231 .name = "wm831x-backlight",
232 .owner = THIS_MODULE,
234 .probe = wm831x_backlight_probe,
235 .remove = wm831x_backlight_remove,
238 static int __init wm831x_backlight_init(void)
240 return platform_driver_register(&wm831x_backlight_driver);
242 module_init(wm831x_backlight_init);
244 static void __exit wm831x_backlight_exit(void)
246 platform_driver_unregister(&wm831x_backlight_driver);
248 module_exit(wm831x_backlight_exit);
250 MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
251 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
252 MODULE_LICENSE("GPL");
253 MODULE_ALIAS("platform:wm831x-backlight");