2 * Copyright (c) 2016 Google, Inc
3 * Written by Simon Glass <sjg@chromium.org>
5 * SPDX-License-Identifier: GPL-2.0+
10 #include <backlight.h>
13 #include <power/regulator.h>
15 struct pwm_backlight_priv {
17 struct gpio_desc enable;
26 static int pwm_backlight_enable(struct udevice *dev)
28 struct pwm_backlight_priv *priv = dev_get_priv(dev);
29 struct dm_regulator_uclass_platdata *plat;
34 plat = dev_get_uclass_platdata(priv->reg);
35 debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__,
36 dev->name, priv->reg->name, plat->name);
37 ret = regulator_set_enable(priv->reg, true);
39 debug("%s: Cannot enable regulator for PWM '%s'\n",
46 duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) /
47 (priv->max_level - priv->min_level + 1);
48 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
52 ret = pwm_set_enable(priv->pwm, priv->channel, true);
56 dm_gpio_set_value(&priv->enable, 1);
61 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev)
63 struct pwm_backlight_priv *priv = dev_get_priv(dev);
64 struct ofnode_phandle_args args;
65 int index, ret, count, len;
68 debug("%s: start\n", __func__);
69 ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
70 "power-supply", &priv->reg);
72 debug("%s: Cannot get power supply: ret=%d\n", __func__, ret);
73 ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable,
76 debug("%s: Warning: cannot get enable GPIO: ret=%d\n",
81 ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0,
84 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
88 ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm);
90 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret);
93 priv->channel = args.args[0];
94 priv->period_ns = args.args[1];
96 index = dev_read_u32_default(dev, "default-brightness-level", 255);
97 cell = dev_read_prop(dev, "brightness-levels", &len);
98 count = len / sizeof(u32);
99 if (cell && count > index) {
100 priv->default_level = fdt32_to_cpu(cell[index]);
101 priv->max_level = fdt32_to_cpu(cell[count - 1]);
103 priv->default_level = index;
104 priv->max_level = 255;
106 debug("%s: done\n", __func__);
112 static int pwm_backlight_probe(struct udevice *dev)
117 static const struct backlight_ops pwm_backlight_ops = {
118 .enable = pwm_backlight_enable,
121 static const struct udevice_id pwm_backlight_ids[] = {
122 { .compatible = "pwm-backlight" },
126 U_BOOT_DRIVER(pwm_backlight) = {
127 .name = "pwm_backlight",
128 .id = UCLASS_PANEL_BACKLIGHT,
129 .of_match = pwm_backlight_ids,
130 .ops = &pwm_backlight_ops,
131 .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata,
132 .probe = pwm_backlight_probe,
133 .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv),