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git01.mediatek.com / filogic / uboot / 5e6fe8b51a6519628375f15d9ae42917b1c4fc39 / . / drivers / video / aat2870_backlight.c
blob: 209d15b36395003681d585ee7f18b65874ff2bc3 [file] [log] [blame]
Svyatoslav Ryhel16fbab52024-10-02 12:07:10 +0300[diff] [blame]1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) 2024 Svyatoslav Ryhel <clamor95@gmail.com>
4 */
5
6#define LOG_CATEGORY UCLASS_PANEL_BACKLIGHT
7
8#include <backlight.h>
9#include <dm.h>
10#include <i2c.h>
11#include <log.h>
12#include <linux/err.h>
13#include <asm/gpio.h>
14#include <power/regulator.h>
15
16#define AAT2870_BL_MIN_BRIGHTNESS 0x01
17#define AAT2870_BL_DEF_BRIGHTNESS 0x64
18#define AAT2870_BL_MAX_BRIGHTNESS 0xff
19
20#define AAT2870_BL_CH_EN 0x00
21#define AAT2870_BLM 0x01
22
23#define AAT2870_BL_CH_ALL 0xff
24
25#define AAT2870_CURRENT_MAX 27900000
26#define AAT2870_CURRENT_STEP 900000
27
28struct aat2870_backlight_priv {
29 struct gpio_desc enable_gpio;
30
31 int channels;
32 int max_current;
33};
34
35static int aat2870_backlight_enable(struct udevice *dev)
36{
37 struct aat2870_backlight_priv *priv = dev_get_priv(dev);
38 int ret;
39
40 dm_gpio_set_value(&priv->enable_gpio, 1);
41
42 /* Enable backlight for defined set of channels */
43 ret = dm_i2c_reg_write(dev, AAT2870_BL_CH_EN, priv->channels);
44 if (ret)
45 return ret;
46
47 return 0;
48}
49
50static int aat2870_backlight_set_brightness(struct udevice *dev, int percent)
51{
52 struct aat2870_backlight_priv *priv = dev_get_priv(dev);
53 int brightness, ret;
54
55 if (percent == BACKLIGHT_DEFAULT)
56 percent = AAT2870_BL_DEF_BRIGHTNESS;
57
58 if (percent < AAT2870_BL_MIN_BRIGHTNESS)
59 percent = AAT2870_BL_MIN_BRIGHTNESS;
60
61 if (percent > AAT2870_BL_MAX_BRIGHTNESS)
62 percent = AAT2870_BL_MAX_BRIGHTNESS;
63
64 brightness = percent * priv->max_current;
65 brightness /= AAT2870_BL_MAX_BRIGHTNESS;
66
67 /* Set brightness level */
68 ret = dm_i2c_reg_write(dev, AAT2870_BLM, brightness);
69 if (ret)
70 return ret;
71
72 return 0;
73}
74
75static int aat2870_backlight_of_to_plat(struct udevice *dev)
76{
77 struct aat2870_backlight_priv *priv = dev_get_priv(dev);
78 int ret;
79
80 ret = gpio_request_by_name(dev, "enable-gpios", 0,
81 &priv->enable_gpio, GPIOD_IS_OUT);
82 if (ret) {
83 log_err("%s: cannot get enable-gpios (%d)\n",
84 __func__, ret);
85 return ret;
86 }
87
88 /* Backlight is one of children but has no dedicated driver */
89 ofnode backlight = ofnode_find_subnode(dev_ofnode(dev), "backlight");
90 if (ofnode_valid(backlight) && ofnode_is_enabled(backlight)) {
91 /* Number of channel is equal to bit number */
92 priv->channels = dev_read_u32_default(dev, "channels", AAT2870_BL_CH_ALL);
93 if (priv->channels != AAT2870_BL_CH_ALL)
94 priv->channels = BIT(priv->channels);
95
96 /* 450mA - 27900mA range with a 900mA step */
97 priv->max_current = dev_read_u32_default(dev, "current-max-microamp",
98 AAT2870_CURRENT_MAX);
99 priv->max_current /= AAT2870_CURRENT_STEP;
100 }
101
102 return 0;
103}
104
105static int aat2870_backlight_probe(struct udevice *dev)
106{
107 if (device_get_uclass_id(dev->parent) != UCLASS_I2C)
108 return -EPROTONOSUPPORT;
109
110 return 0;
111}
112
113static const struct backlight_ops aat2870_backlight_ops = {
114 .enable = aat2870_backlight_enable,
115 .set_brightness = aat2870_backlight_set_brightness,
116};
117
118static const struct udevice_id aat2870_backlight_ids[] = {
119 { .compatible = "analogictech,aat2870" },
120 { .compatible = "skyworks,aat2870" },
121 { }
122};
123
124U_BOOT_DRIVER(aat2870_backlight) = {
125 .name = "aat2870_backlight",
126 .id = UCLASS_PANEL_BACKLIGHT,
127 .of_match = aat2870_backlight_ids,
128 .of_to_plat = aat2870_backlight_of_to_plat,
129 .probe = aat2870_backlight_probe,
130 .ops = &aat2870_backlight_ops,
131 .priv_auto = sizeof(struct aat2870_backlight_priv),
132};