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 bool polarity; 24 uint default_level; 25 uint min_level; 26 uint max_level; 27 }; 28 29 static int pwm_backlight_enable(struct udevice *dev) 30 { 31 struct pwm_backlight_priv *priv = dev_get_priv(dev); 32 struct dm_regulator_uclass_platdata *plat; 33 uint duty_cycle; 34 int ret; 35 36 if (priv->reg) { 37 plat = dev_get_uclass_platdata(priv->reg); 38 debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__, 39 dev->name, priv->reg->name, plat->name); 40 ret = regulator_set_enable(priv->reg, true); 41 if (ret) { 42 debug("%s: Cannot enable regulator for PWM '%s'\n", 43 __func__, dev->name); 44 return ret; 45 } 46 mdelay(120); 47 } 48 49 ret = pwm_set_invert(priv->pwm, priv->channel, priv->polarity); 50 if (ret) { 51 dev_err(dev, "Failed to invert PWM\n"); 52 return ret; 53 } 54 55 duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) / 56 (priv->max_level - priv->min_level + 1); 57 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns, 58 duty_cycle); 59 if (ret) 60 return ret; 61 ret = pwm_set_enable(priv->pwm, priv->channel, true); 62 if (ret) 63 return ret; 64 mdelay(10); 65 66 if (dm_gpio_is_valid(&priv->enable)) 67 dm_gpio_set_value(&priv->enable, 1); 68 69 return 0; 70 } 71 72 static int pwm_backlight_disable(struct udevice *dev) 73 { 74 struct pwm_backlight_priv *priv = dev_get_priv(dev); 75 struct dm_regulator_uclass_platdata *plat; 76 int ret; 77 78 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns, 0); 79 if (ret) 80 return ret; 81 82 /* 83 * Sometimes there is not "enable-gpios", we have to set pwm output 84 * 0% or 100% duty to play role like "enable-gpios", so we should not 85 * disable pwm, let's keep it enabled. 86 */ 87 if (dm_gpio_is_valid(&priv->enable)) { 88 ret = pwm_set_enable(priv->pwm, priv->channel, false); 89 if (ret) 90 return ret; 91 } 92 93 mdelay(10); 94 if (dm_gpio_is_valid(&priv->enable)) 95 dm_gpio_set_value(&priv->enable, 0); 96 97 if (priv->reg) { 98 plat = dev_get_uclass_platdata(priv->reg); 99 debug("%s: Disable '%s', regulator '%s'/'%s'\n", __func__, 100 dev->name, priv->reg->name, plat->name); 101 ret = regulator_set_enable(priv->reg, false); 102 if (ret) { 103 debug("%s: Cannot enable regulator for PWM '%s'\n", 104 __func__, dev->name); 105 } 106 mdelay(120); 107 } 108 109 return 0; 110 } 111 112 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) 113 { 114 struct pwm_backlight_priv *priv = dev_get_priv(dev); 115 struct ofnode_phandle_args args; 116 int index, ret, count, len; 117 const u32 *cell; 118 119 debug("%s: start\n", __func__); 120 ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev, 121 "power-supply", &priv->reg); 122 if (ret) 123 debug("%s: Cannot get power supply: ret=%d\n", __func__, ret); 124 ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable, 125 GPIOD_IS_OUT); 126 if (ret) { 127 debug("%s: Warning: cannot get enable GPIO: ret=%d\n", 128 __func__, ret); 129 if (ret != -ENOENT) 130 return ret; 131 } 132 ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, 133 &args); 134 if (ret) { 135 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); 136 return ret; 137 } 138 139 ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm); 140 if (ret) { 141 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); 142 return ret; 143 } 144 priv->channel = args.args[0]; 145 priv->period_ns = args.args[1]; 146 priv->polarity = args.args[2]; 147 148 index = dev_read_u32_default(dev, "default-brightness-level", 255); 149 cell = dev_read_prop(dev, "brightness-levels", &len); 150 count = len / sizeof(u32); 151 if (cell && count > index) { 152 priv->default_level = fdt32_to_cpu(cell[index]); 153 priv->max_level = fdt32_to_cpu(cell[count - 1]); 154 /* Rockchip dts may use a invert sequence level array */ 155 if(fdt32_to_cpu(cell[0]) > priv->max_level) 156 priv->max_level = fdt32_to_cpu(cell[0]); 157 } else { 158 priv->default_level = index; 159 priv->max_level = 255; 160 } 161 debug("%s: done\n", __func__); 162 163 164 return 0; 165 } 166 167 static int pwm_backlight_probe(struct udevice *dev) 168 { 169 return 0; 170 } 171 172 static const struct backlight_ops pwm_backlight_ops = { 173 .enable = pwm_backlight_enable, 174 .disable = pwm_backlight_disable, 175 }; 176 177 static const struct udevice_id pwm_backlight_ids[] = { 178 { .compatible = "pwm-backlight" }, 179 { } 180 }; 181 182 U_BOOT_DRIVER(pwm_backlight) = { 183 .name = "pwm_backlight", 184 .id = UCLASS_PANEL_BACKLIGHT, 185 .of_match = pwm_backlight_ids, 186 .ops = &pwm_backlight_ops, 187 .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata, 188 .probe = pwm_backlight_probe, 189 .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv), 190 }; 191