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 59 if (dm_gpio_is_valid(&priv->enable)) 60 dm_gpio_set_value(&priv->enable, 1); 61 62 return 0; 63 } 64 65 static int pwm_backlight_disable(struct udevice *dev) 66 { 67 struct pwm_backlight_priv *priv = dev_get_priv(dev); 68 struct dm_regulator_uclass_platdata *plat; 69 int ret; 70 71 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns, 0); 72 if (ret) 73 return ret; 74 75 /* 76 * Sometimes there is not "enable-gpios", we have to set pwm output 77 * 0% or 100% duty to play role like "enable-gpios", so we should not 78 * disable pwm, let's keep it enabled. 79 */ 80 if (dm_gpio_is_valid(&priv->enable)) { 81 ret = pwm_set_enable(priv->pwm, priv->channel, false); 82 if (ret) 83 return ret; 84 } 85 86 mdelay(10); 87 if (dm_gpio_is_valid(&priv->enable)) 88 dm_gpio_set_value(&priv->enable, 0); 89 90 if (priv->reg) { 91 plat = dev_get_uclass_platdata(priv->reg); 92 debug("%s: Disable '%s', regulator '%s'/'%s'\n", __func__, 93 dev->name, priv->reg->name, plat->name); 94 ret = regulator_set_enable(priv->reg, false); 95 if (ret) { 96 debug("%s: Cannot enable regulator for PWM '%s'\n", 97 __func__, dev->name); 98 } 99 mdelay(120); 100 } 101 102 return 0; 103 } 104 105 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) 106 { 107 struct pwm_backlight_priv *priv = dev_get_priv(dev); 108 struct ofnode_phandle_args args; 109 int index, ret, count, len; 110 const u32 *cell; 111 112 debug("%s: start\n", __func__); 113 ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev, 114 "power-supply", &priv->reg); 115 if (ret) 116 debug("%s: Cannot get power supply: ret=%d\n", __func__, ret); 117 ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable, 118 GPIOD_IS_OUT); 119 if (ret) { 120 debug("%s: Warning: cannot get enable GPIO: ret=%d\n", 121 __func__, ret); 122 if (ret != -ENOENT) 123 return ret; 124 } 125 ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, 126 &args); 127 if (ret) { 128 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); 129 return ret; 130 } 131 132 ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm); 133 if (ret) { 134 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); 135 return ret; 136 } 137 priv->channel = args.args[0]; 138 priv->period_ns = args.args[1]; 139 140 index = dev_read_u32_default(dev, "default-brightness-level", 255); 141 cell = dev_read_prop(dev, "brightness-levels", &len); 142 count = len / sizeof(u32); 143 if (cell && count > index) { 144 priv->default_level = fdt32_to_cpu(cell[index]); 145 priv->max_level = fdt32_to_cpu(cell[count - 1]); 146 /* Rockchip dts may use a invert sequence level array */ 147 if(fdt32_to_cpu(cell[0]) > priv->max_level) 148 priv->max_level = fdt32_to_cpu(cell[0]); 149 } else { 150 priv->default_level = index; 151 priv->max_level = 255; 152 } 153 debug("%s: done\n", __func__); 154 155 156 return 0; 157 } 158 159 static int pwm_backlight_probe(struct udevice *dev) 160 { 161 return 0; 162 } 163 164 static const struct backlight_ops pwm_backlight_ops = { 165 .enable = pwm_backlight_enable, 166 .disable = pwm_backlight_disable, 167 }; 168 169 static const struct udevice_id pwm_backlight_ids[] = { 170 { .compatible = "pwm-backlight" }, 171 { } 172 }; 173 174 U_BOOT_DRIVER(pwm_backlight) = { 175 .name = "pwm_backlight", 176 .id = UCLASS_PANEL_BACKLIGHT, 177 .of_match = pwm_backlight_ids, 178 .ops = &pwm_backlight_ops, 179 .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata, 180 .probe = pwm_backlight_probe, 181 .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv), 182 }; 183