1 // SPDX-License-Identifier: GPL-2.0-only
3 * Backlight driver for Wolfson Microelectronics WM831x PMICs
5 * Copyright 2009 Wolfson Microelectonics plc
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/platform_device.h>
11 #include <linux/module.h>
13 #include <linux/backlight.h>
14 #include <linux/slab.h>
16 #include <linux/mfd/wm831x/core.h>
17 #include <linux/mfd/wm831x/pdata.h>
18 #include <linux/mfd/wm831x/regulator.h>
20 struct wm831x_backlight_data {
21 struct wm831x *wm831x;
23 int current_brightness;
26 static int wm831x_backlight_set(struct backlight_device *bl, int brightness)
28 struct wm831x_backlight_data *data = bl_get_data(bl);
29 struct wm831x *wm831x = data->wm831x;
30 int power_up = !data->current_brightness && brightness;
31 int power_down = data->current_brightness && !brightness;
35 /* Enable the ISINK */
36 ret = wm831x_set_bits(wm831x, data->isink_reg,
37 WM831X_CS1_ENA, WM831X_CS1_ENA);
41 /* Enable the DC-DC */
42 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
43 WM831X_DC4_ENA, WM831X_DC4_ENA);
50 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
56 ret = wm831x_set_bits(wm831x, data->isink_reg,
57 WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0);
62 /* Set the new brightness */
63 ret = wm831x_set_bits(wm831x, data->isink_reg,
64 WM831X_CS1_ISEL_MASK, brightness);
69 /* Drive current through the ISINK */
70 ret = wm831x_set_bits(wm831x, data->isink_reg,
71 WM831X_CS1_DRIVE, WM831X_CS1_DRIVE);
76 data->current_brightness = brightness;
81 /* If we were in the middle of a power transition always shut down
84 if (power_up || power_down) {
85 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
86 wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0);
92 static int wm831x_backlight_update_status(struct backlight_device *bl)
94 int brightness = bl->props.brightness;
96 if (bl->props.power != FB_BLANK_UNBLANK)
99 if (bl->props.fb_blank != FB_BLANK_UNBLANK)
102 if (bl->props.state & BL_CORE_SUSPENDED)
105 return wm831x_backlight_set(bl, brightness);
108 static int wm831x_backlight_get_brightness(struct backlight_device *bl)
110 struct wm831x_backlight_data *data = bl_get_data(bl);
112 return data->current_brightness;
115 static const 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,
121 static int wm831x_backlight_probe(struct platform_device *pdev)
123 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
124 struct wm831x_pdata *wm831x_pdata = dev_get_platdata(pdev->dev.parent);
125 struct wm831x_backlight_pdata *pdata;
126 struct wm831x_backlight_data *data;
127 struct backlight_device *bl;
128 struct backlight_properties props;
129 int ret, i, max_isel, isink_reg, dcdc_cfg;
131 /* We need platform data */
133 pdata = wm831x_pdata->backlight;
138 dev_err(&pdev->dev, "No platform data supplied\n");
142 /* Figure out the maximum current we can use */
143 for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) {
144 if (wm831x_isinkv_values[i] > pdata->max_uA)
149 dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
154 if (pdata->max_uA != wm831x_isinkv_values[max_isel])
156 "Maximum current is %duA not %duA as requested\n",
157 wm831x_isinkv_values[max_isel], pdata->max_uA);
159 switch (pdata->isink) {
161 isink_reg = WM831X_CURRENT_SINK_1;
165 isink_reg = WM831X_CURRENT_SINK_2;
166 dcdc_cfg = WM831X_DC4_FBSRC;
169 dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
173 /* Configure the ISINK to use for feedback */
174 ret = wm831x_reg_unlock(wm831x);
178 ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
181 wm831x_reg_lock(wm831x);
185 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
189 data->wm831x = wm831x;
190 data->current_brightness = 0;
191 data->isink_reg = isink_reg;
193 memset(&props, 0, sizeof(props));
194 props.type = BACKLIGHT_RAW;
195 props.max_brightness = max_isel;
196 bl = devm_backlight_device_register(&pdev->dev, "wm831x", &pdev->dev,
197 data, &wm831x_backlight_ops, &props);
199 dev_err(&pdev->dev, "failed to register backlight\n");
203 bl->props.brightness = max_isel;
205 platform_set_drvdata(pdev, bl);
207 /* Disable the DCDC if it was started so we can bootstrap */
208 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
210 backlight_update_status(bl);
215 static struct platform_driver wm831x_backlight_driver = {
217 .name = "wm831x-backlight",
219 .probe = wm831x_backlight_probe,
222 module_platform_driver(wm831x_backlight_driver);
224 MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
225 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
226 MODULE_LICENSE("GPL");
227 MODULE_ALIAS("platform:wm831x-backlight");