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 if (priv->reg) { 36 plat = dev_get_uclass_platdata(priv->reg); 37 debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__, 38 dev->name, priv->reg->name, plat->name); 39 ret = regulator_set_enable(priv->reg, true); 40 if (ret) { 41 debug("%s: Cannot enable regulator for PWM '%s'\n", 42 __func__, dev->name); 43 return ret; 44 } 45 mdelay(120); 46 } 47 48 duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) / 49 (priv->max_level - priv->min_level + 1); 50 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns, 51 duty_cycle); 52 if (ret) 53 return ret; 54 ret = pwm_set_enable(priv->pwm, priv->channel, true); 55 if (ret) 56 return ret; 57 mdelay(10); 58 dm_gpio_set_value(&priv->enable, 1); 59 60 return 0; 61 } 62 63 static int pwm_backlight_disable(struct udevice *dev) 64 { 65 struct pwm_backlight_priv *priv = dev_get_priv(dev); 66 struct dm_regulator_uclass_platdata *plat; 67 uint duty_cycle; 68 int ret; 69 70 duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) / 71 (priv->max_level - priv->min_level + 1); 72 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns, 73 duty_cycle); 74 if (ret) 75 return ret; 76 77 ret = pwm_set_enable(priv->pwm, priv->channel, false); 78 if (ret) 79 return ret; 80 81 mdelay(10); 82 dm_gpio_set_value(&priv->enable, 0); 83 84 if (priv->reg) { 85 plat = dev_get_uclass_platdata(priv->reg); 86 debug("%s: Disable '%s', regulator '%s'/'%s'\n", __func__, 87 dev->name, priv->reg->name, plat->name); 88 ret = regulator_set_enable(priv->reg, false); 89 if (ret) { 90 debug("%s: Cannot enable regulator for PWM '%s'\n", 91 __func__, dev->name); 92 } 93 mdelay(120); 94 } 95 96 return 0; 97 } 98 99 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) 100 { 101 struct pwm_backlight_priv *priv = dev_get_priv(dev); 102 struct ofnode_phandle_args args; 103 int index, ret, count, len; 104 const u32 *cell; 105 106 debug("%s: start\n", __func__); 107 ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev, 108 "power-supply", &priv->reg); 109 if (ret) 110 debug("%s: Cannot get power supply: ret=%d\n", __func__, ret); 111 ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable, 112 GPIOD_IS_OUT); 113 if (ret) { 114 debug("%s: Warning: cannot get enable GPIO: ret=%d\n", 115 __func__, ret); 116 if (ret != -ENOENT) 117 return ret; 118 } 119 ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, 120 &args); 121 if (ret) { 122 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); 123 return ret; 124 } 125 126 ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm); 127 if (ret) { 128 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); 129 return ret; 130 } 131 priv->channel = args.args[0]; 132 priv->period_ns = args.args[1]; 133 134 index = dev_read_u32_default(dev, "default-brightness-level", 255); 135 cell = dev_read_prop(dev, "brightness-levels", &len); 136 count = len / sizeof(u32); 137 if (cell && count > index) { 138 priv->default_level = fdt32_to_cpu(cell[index]); 139 priv->max_level = fdt32_to_cpu(cell[count - 1]); 140 /* Rockchip dts may use a invert sequence level array */ 141 if(fdt32_to_cpu(cell[0]) > priv->max_level) 142 priv->max_level = fdt32_to_cpu(cell[0]); 143 } else { 144 priv->default_level = index; 145 priv->max_level = 255; 146 } 147 debug("%s: done\n", __func__); 148 149 150 return 0; 151 } 152 153 static int pwm_backlight_probe(struct udevice *dev) 154 { 155 return 0; 156 } 157 158 static const struct backlight_ops pwm_backlight_ops = { 159 .enable = pwm_backlight_enable, 160 .disable = pwm_backlight_disable, 161 }; 162 163 static const struct udevice_id pwm_backlight_ids[] = { 164 { .compatible = "pwm-backlight" }, 165 { } 166 }; 167 168 U_BOOT_DRIVER(pwm_backlight) = { 169 .name = "pwm_backlight", 170 .id = UCLASS_PANEL_BACKLIGHT, 171 .of_match = pwm_backlight_ids, 172 .ops = &pwm_backlight_ops, 173 .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata, 174 .probe = pwm_backlight_probe, 175 .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv), 176 }; 177