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 uint duty_cycle; 32 int ret; 33 34 debug("%s: Enable '%s', regulator '%s'\n", __func__, dev->name, 35 priv->reg->name); 36 ret = regulator_set_enable(priv->reg, true); 37 if (ret) { 38 debug("%s: Cannot enable regulator for PWM '%s'\n", __func__, 39 dev->name); 40 return ret; 41 } 42 mdelay(120); 43 44 duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) / 45 (priv->max_level - priv->min_level + 1); 46 ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns, 47 duty_cycle); 48 if (ret) 49 return ret; 50 ret = pwm_set_enable(priv->pwm, priv->channel, true); 51 if (ret) 52 return ret; 53 mdelay(10); 54 dm_gpio_set_value(&priv->enable, 1); 55 56 return 0; 57 } 58 59 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) 60 { 61 struct pwm_backlight_priv *priv = dev_get_priv(dev); 62 struct fdtdec_phandle_args args; 63 const void *blob = gd->fdt_blob; 64 int node = dev->of_offset; 65 int index, ret, count, len; 66 const u32 *cell; 67 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 return ret; 73 } 74 ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable, 75 GPIOD_IS_OUT); 76 if (ret) { 77 debug("%s: Warning: cannot get enable GPIO: ret=%d\n", 78 __func__, ret); 79 if (ret != -ENOENT) 80 return ret; 81 } 82 ret = fdtdec_parse_phandle_with_args(blob, node, "pwms", "#pwm-cells", 83 0, 0, &args); 84 if (ret) { 85 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); 86 return ret; 87 } 88 89 ret = uclass_get_device_by_of_offset(UCLASS_PWM, args.node, &priv->pwm); 90 if (ret) { 91 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); 92 return ret; 93 } 94 priv->channel = args.args[0]; 95 priv->period_ns = args.args[1]; 96 97 index = fdtdec_get_int(blob, node, "default-brightness-level", 255); 98 cell = fdt_getprop(blob, node, "brightness-levels", &len); 99 count = len / sizeof(u32); 100 if (cell && count > index) { 101 priv->default_level = fdt32_to_cpu(cell[index]); 102 priv->max_level = fdt32_to_cpu(cell[count - 1]); 103 } else { 104 priv->default_level = index; 105 priv->max_level = 255; 106 } 107 108 109 return 0; 110 } 111 112 static int pwm_backlight_probe(struct udevice *dev) 113 { 114 return 0; 115 } 116 117 static const struct backlight_ops pwm_backlight_ops = { 118 .enable = pwm_backlight_enable, 119 }; 120 121 static const struct udevice_id pwm_backlight_ids[] = { 122 { .compatible = "pwm-backlight" }, 123 { } 124 }; 125 126 U_BOOT_DRIVER(pwm_backlight) = { 127 .name = "pwm_backlight", 128 .id = UCLASS_PANEL_BACKLIGHT, 129 .of_match = pwm_backlight_ids, 130 .ops = &pwm_backlight_ops, 131 .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata, 132 .probe = pwm_backlight_probe, 133 .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv), 134 }; 135