1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (c) 2016 Google, Inc 4 * Written by Simon Glass <sjg@chromium.org> 5 */ 6 7 #include <common.h> 8 #include <dm.h> 9 #include <backlight.h> 10 #include <pwm.h> 11 #include <asm/gpio.h> 12 #include <power/regulator.h> 13 14 struct pwm_backlight_priv { 15 struct udevice *reg; 16 struct gpio_desc enable; 17 struct udevice *pwm; 18 uint channel; 19 uint period_ns; 20 uint default_level; 21 uint min_level; 22 uint max_level; 23 }; 24 25 static int pwm_backlight_enable(struct udevice *dev) 26 { 27 struct pwm_backlight_priv *priv = dev_get_priv(dev); 28 struct dm_regulator_uclass_platdata *plat; 29 uint duty_cycle; 30 int ret; 31 32 if (priv->reg) { 33 plat = dev_get_uclass_platdata(priv->reg); 34 debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__, 35 dev->name, priv->reg->name, plat->name); 36 ret = regulator_set_enable(priv->reg, true); 37 if (ret) { 38 debug("%s: Cannot enable regulator for PWM '%s'\n", 39 __func__, dev->name); 40 return ret; 41 } 42 mdelay(120); 43 } 44 45 duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) / 46 (priv->max_level - priv->min_level + 1); 47 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns, 48 duty_cycle); 49 if (ret) 50 return ret; 51 ret = pwm_set_enable(priv->pwm, priv->channel, true); 52 if (ret) 53 return ret; 54 mdelay(10); 55 dm_gpio_set_value(&priv->enable, 1); 56 57 return 0; 58 } 59 60 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) 61 { 62 struct pwm_backlight_priv *priv = dev_get_priv(dev); 63 struct ofnode_phandle_args args; 64 int index, ret, count, len; 65 const u32 *cell; 66 67 debug("%s: start\n", __func__); 68 ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev, 69 "power-supply", &priv->reg); 70 if (ret) 71 debug("%s: Cannot get power supply: ret=%d\n", __func__, ret); 72 ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable, 73 GPIOD_IS_OUT); 74 if (ret) { 75 debug("%s: Warning: cannot get enable GPIO: ret=%d\n", 76 __func__, ret); 77 if (ret != -ENOENT) 78 return ret; 79 } 80 ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, 81 &args); 82 if (ret) { 83 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); 84 return ret; 85 } 86 87 ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm); 88 if (ret) { 89 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); 90 return ret; 91 } 92 priv->channel = args.args[0]; 93 priv->period_ns = args.args[1]; 94 95 index = dev_read_u32_default(dev, "default-brightness-level", 255); 96 cell = dev_read_prop(dev, "brightness-levels", &len); 97 count = len / sizeof(u32); 98 if (cell && count > index) { 99 priv->default_level = fdt32_to_cpu(cell[index]); 100 priv->max_level = fdt32_to_cpu(cell[count - 1]); 101 } else { 102 priv->default_level = index; 103 priv->max_level = 255; 104 } 105 debug("%s: done\n", __func__); 106 107 108 return 0; 109 } 110 111 static int pwm_backlight_probe(struct udevice *dev) 112 { 113 return 0; 114 } 115 116 static const struct backlight_ops pwm_backlight_ops = { 117 .enable = pwm_backlight_enable, 118 }; 119 120 static const struct udevice_id pwm_backlight_ids[] = { 121 { .compatible = "pwm-backlight" }, 122 { } 123 }; 124 125 U_BOOT_DRIVER(pwm_backlight) = { 126 .name = "pwm_backlight", 127 .id = UCLASS_PANEL_BACKLIGHT, 128 .of_match = pwm_backlight_ids, 129 .ops = &pwm_backlight_ops, 130 .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata, 131 .probe = pwm_backlight_probe, 132 .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv), 133 }; 134