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>
14 #include <linux/module.h>
16 #include <linux/backlight.h>
17 #include <linux/slab.h>
19 #include <linux/mfd/wm831x/core.h>
20 #include <linux/mfd/wm831x/pdata.h>
21 #include <linux/mfd/wm831x/regulator.h>
23 struct wm831x_backlight_data {
24 struct wm831x *wm831x;
26 int current_brightness;
29 static int wm831x_backlight_set(struct backlight_device *bl, int brightness)
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;
38 /* Enable the ISINK */
39 ret = wm831x_set_bits(wm831x, data->isink_reg,
40 WM831X_CS1_ENA, WM831X_CS1_ENA);
44 /* Enable the DC-DC */
45 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
46 WM831X_DC4_ENA, WM831X_DC4_ENA);
53 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
59 ret = wm831x_set_bits(wm831x, data->isink_reg,
60 WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0);
65 /* Set the new brightness */
66 ret = wm831x_set_bits(wm831x, data->isink_reg,
67 WM831X_CS1_ISEL_MASK, brightness);
72 /* Drive current through the ISINK */
73 ret = wm831x_set_bits(wm831x, data->isink_reg,
74 WM831X_CS1_DRIVE, WM831X_CS1_DRIVE);
79 data->current_brightness = brightness;
84 /* If we were in the middle of a power transition always shut down
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);
95 static int wm831x_backlight_update_status(struct backlight_device *bl)
97 int brightness = bl->props.brightness;
99 if (bl->props.power != FB_BLANK_UNBLANK)
102 if (bl->props.fb_blank != FB_BLANK_UNBLANK)
105 if (bl->props.state & BL_CORE_SUSPENDED)
108 return wm831x_backlight_set(bl, brightness);
111 static int wm831x_backlight_get_brightness(struct backlight_device *bl)
113 struct wm831x_backlight_data *data = bl_get_data(bl);
114 return data->current_brightness;
117 static const struct backlight_ops wm831x_backlight_ops = {
118 .options = BL_CORE_SUSPENDRESUME,
119 .update_status = wm831x_backlight_update_status,
120 .get_brightness = wm831x_backlight_get_brightness,
123 static int wm831x_backlight_probe(struct platform_device *pdev)
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;
130 struct backlight_properties props;
131 int ret, i, max_isel, isink_reg, dcdc_cfg;
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;
142 dev_err(&pdev->dev, "No platform data supplied\n");
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)
153 dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
158 if (pdata->max_uA != wm831x_isinkv_values[max_isel])
160 "Maximum current is %duA not %duA as requested\n",
161 wm831x_isinkv_values[max_isel], pdata->max_uA);
163 switch (pdata->isink) {
165 isink_reg = WM831X_CURRENT_SINK_1;
169 isink_reg = WM831X_CURRENT_SINK_2;
170 dcdc_cfg = WM831X_DC4_FBSRC;
173 dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
177 /* Configure the ISINK to use for feedback */
178 ret = wm831x_reg_unlock(wm831x);
182 ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
185 wm831x_reg_lock(wm831x);
189 data = kzalloc(sizeof(*data), GFP_KERNEL);
193 data->wm831x = wm831x;
194 data->current_brightness = 0;
195 data->isink_reg = isink_reg;
197 props.type = BACKLIGHT_RAW;
198 props.max_brightness = max_isel;
199 bl = backlight_device_register("wm831x", &pdev->dev, data,
200 &wm831x_backlight_ops, &props);
202 dev_err(&pdev->dev, "failed to register backlight\n");
207 bl->props.brightness = max_isel;
209 platform_set_drvdata(pdev, bl);
211 /* Disable the DCDC if it was started so we can bootstrap */
212 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
215 backlight_update_status(bl);
220 static int wm831x_backlight_remove(struct platform_device *pdev)
222 struct backlight_device *bl = platform_get_drvdata(pdev);
223 struct wm831x_backlight_data *data = bl_get_data(bl);
225 backlight_device_unregister(bl);
230 static struct platform_driver wm831x_backlight_driver = {
232 .name = "wm831x-backlight",
233 .owner = THIS_MODULE,
235 .probe = wm831x_backlight_probe,
236 .remove = wm831x_backlight_remove,
239 static int __init wm831x_backlight_init(void)
241 return platform_driver_register(&wm831x_backlight_driver);
243 module_init(wm831x_backlight_init);
245 static void __exit wm831x_backlight_exit(void)
247 platform_driver_unregister(&wm831x_backlight_driver);
249 module_exit(wm831x_backlight_exit);
251 MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
252 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
253 MODULE_LICENSE("GPL");
254 MODULE_ALIAS("platform:wm831x-backlight");