018d3c99b4
Add support for PWM backlight found in Samsung CMC623 image converter. Signed-off-by: Ion Agorria <ion@agorria.com> Reviewed-by: Svyatoslav Ryhel <clamor95@gmail.com> Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
125 lines
2.8 KiB
C
125 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2025 Ion Agorria <ion@agorria.com>
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*/
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#define LOG_CATEGORY UCLASS_PANEL_BACKLIGHT
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#include <backlight.h>
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#include <dm.h>
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#include <i2c.h>
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#include <log.h>
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#include <linux/err.h>
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#include <asm/gpio.h>
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#include <power/regulator.h>
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#define CMC623_I2C_REG_SELBANK 0x00
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#define CMC623_I2C_REG_PWMCTRL 0xb4
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#define CMC623_I2C_REG_REGMASK 0x28
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#define CMC623_BL_MIN_BRIGHTNESS 0
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#define CMC623_BL_DEF_BRIGHTNESS 50
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#define CMC623_BL_MAX_BRIGHTNESS 100
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struct cmc623_backlight_priv {
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struct gpio_desc enable_gpio;
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};
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static int cmc623_backlight_enable(struct udevice *dev)
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{
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struct cmc623_backlight_priv *priv = dev_get_priv(dev);
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if (dm_gpio_is_valid(&priv->enable_gpio))
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dm_gpio_set_value(&priv->enable_gpio, 1);
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return 0;
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}
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static int cmc623_i2c_write(struct udevice *dev, u8 reg, u16 value)
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{
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u8 data[2];
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data[0] = (value >> 8) & 0xff;
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data[1] = value & 0xff;
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return dm_i2c_write(dev->parent, reg, data, 2);
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}
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static int cmc623_backlight_set_brightness(struct udevice *dev, int percent)
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{
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int ret;
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u16 brightness;
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if (percent == BACKLIGHT_DEFAULT)
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percent = CMC623_BL_DEF_BRIGHTNESS;
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if (percent < CMC623_BL_MIN_BRIGHTNESS)
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percent = CMC623_BL_MIN_BRIGHTNESS;
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if (percent > CMC623_BL_MAX_BRIGHTNESS)
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percent = CMC623_BL_MAX_BRIGHTNESS;
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brightness = 0x4000 | (percent << 4);
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ret = cmc623_i2c_write(dev, CMC623_I2C_REG_SELBANK, 0x0000);
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if (ret) {
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log_debug("%s: error at CMC623_I2C_REG_SELBANK (%d)\n",
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__func__, ret);
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return ret;
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}
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ret = cmc623_i2c_write(dev, CMC623_I2C_REG_PWMCTRL, brightness);
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if (ret) {
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log_debug("%s: error at CMC623_I2C_REG_PWMCTRL (%d)\n",
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__func__, ret);
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return ret;
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}
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ret = cmc623_i2c_write(dev, CMC623_I2C_REG_REGMASK, 0x0000);
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if (ret) {
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log_debug("%s: error at CMC623_I2C_REG_REGMASK (%d)\n",
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__func__, ret);
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return ret;
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}
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return 0;
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}
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static int cmc623_backlight_of_to_plat(struct udevice *dev)
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{
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struct cmc623_backlight_priv *priv = dev_get_priv(dev);
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gpio_request_by_name(dev, "enable-gpios", 0,
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&priv->enable_gpio, GPIOD_IS_OUT);
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return 0;
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}
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static int cmc623_backlight_probe(struct udevice *dev)
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{
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if (device_get_uclass_id(dev->parent) != UCLASS_VIDEO_BRIDGE)
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return -EPROTONOSUPPORT;
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return 0;
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}
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static const struct backlight_ops cmc623_backlight_ops = {
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.enable = cmc623_backlight_enable,
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.set_brightness = cmc623_backlight_set_brightness,
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};
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static const struct udevice_id cmc623_backlight_ids[] = {
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{ .compatible = "samsung,cmc623-backlight" },
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{ }
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};
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U_BOOT_DRIVER(cmc623_backlight) = {
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.name = "cmc623_backlight",
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.id = UCLASS_PANEL_BACKLIGHT,
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.of_match = cmc623_backlight_ids,
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.of_to_plat = cmc623_backlight_of_to_plat,
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.probe = cmc623_backlight_probe,
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.ops = &cmc623_backlight_ops,
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.priv_auto = sizeof(struct cmc623_backlight_priv),
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};
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