1 /* 2 * Copyright (c) 2016 Google, Inc 3 * Written by Simon Glass <sjg@chromium.org> 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <common.h> 9 #include <dm.h> 10 #include <backlight.h> 11 #include <pwm.h> 12 #include <asm/gpio.h> 13 #include <power/regulator.h> 14 15 DECLARE_GLOBAL_DATA_PTR; 16 17 struct pwm_backlight_priv { 18 struct udevice *reg; 19 struct gpio_desc enable; 20 struct udevice *pwm; 21 uint channel; 22 uint period_ns; 23 uint default_level; 24 uint min_level; 25 uint max_level; 26 }; 27 28 static int pwm_backlight_enable(struct udevice *dev) 29 { 30 struct pwm_backlight_priv *priv = dev_get_priv(dev); 31 struct dm_regulator_uclass_platdata *plat; 32 uint duty_cycle; 33 int ret; 34 35 plat = dev_get_uclass_platdata(priv->reg); 36 debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__, dev->name, 37 priv->reg->name, plat->name); 38 ret = regulator_set_enable(priv->reg, true); 39 if (ret) { 40 debug("%s: Cannot enable regulator for PWM '%s'\n", __func__, 41 dev->name); 42 return ret; 43 } 44 mdelay(120); 45 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, 49 duty_cycle); 50 if (ret) 51 return ret; 52 ret = pwm_set_enable(priv->pwm, priv->channel, true); 53 if (ret) 54 return ret; 55 mdelay(10); 56 dm_gpio_set_value(&priv->enable, 1); 57 58 return 0; 59 } 60 61 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) 62 { 63 struct pwm_backlight_priv *priv = dev_get_priv(dev); 64 struct ofnode_phandle_args args; 65 int index, ret, count, len; 66 const u32 *cell; 67 68 debug("%s: start\n", __func__); 69 ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev, 70 "power-supply", &priv->reg); 71 if (ret) { 72 debug("%s: Cannot get power supply: ret=%d\n", __func__, ret); 73 return ret; 74 } 75 ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable, 76 GPIOD_IS_OUT); 77 if (ret) { 78 debug("%s: Warning: cannot get enable GPIO: ret=%d\n", 79 __func__, ret); 80 if (ret != -ENOENT) 81 return ret; 82 } 83 ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, 84 &args); 85 if (ret) { 86 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); 87 return ret; 88 } 89 90 ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm); 91 if (ret) { 92 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); 93 return ret; 94 } 95 priv->channel = args.args[0]; 96 priv->period_ns = args.args[1]; 97 98 index = dev_read_u32_default(dev, "default-brightness-level", 255); 99 cell = dev_read_prop(dev, "brightness-levels", &len); 100 count = len / sizeof(u32); 101 if (cell && count > index) { 102 priv->default_level = fdt32_to_cpu(cell[index]); 103 priv->max_level = fdt32_to_cpu(cell[count - 1]); 104 } else { 105 priv->default_level = index; 106 priv->max_level = 255; 107 } 108 debug("%s: done\n", __func__); 109 110 111 return 0; 112 } 113 114 static int pwm_backlight_probe(struct udevice *dev) 115 { 116 return 0; 117 } 118 119 static const struct backlight_ops pwm_backlight_ops = { 120 .enable = pwm_backlight_enable, 121 }; 122 123 static const struct udevice_id pwm_backlight_ids[] = { 124 { .compatible = "pwm-backlight" }, 125 { } 126 }; 127 128 U_BOOT_DRIVER(pwm_backlight) = { 129 .name = "pwm_backlight", 130 .id = UCLASS_PANEL_BACKLIGHT, 131 .of_match = pwm_backlight_ids, 132 .ops = &pwm_backlight_ops, 133 .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata, 134 .probe = pwm_backlight_probe, 135 .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv), 136 }; 137