352 lines
9.7 KiB
C
352 lines
9.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2022 Richtek Technology Corp.
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*
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* Author: ChiaEn Wu <chiaen_wu@richtek.com>
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*/
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#include <linux/backlight.h>
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#include <linux/bitfield.h>
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#include <linux/bits.h>
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#include <linux/gpio/consumer.h>
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#include <linux/kernel.h>
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#include <linux/minmax.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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#include <linux/regmap.h>
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#define MT6370_REG_DEV_INFO 0x100
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#define MT6370_REG_BL_EN 0x1A0
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#define MT6370_REG_BL_BSTCTRL 0x1A1
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#define MT6370_REG_BL_PWM 0x1A2
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#define MT6370_REG_BL_DIM2 0x1A4
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#define MT6370_VENID_MASK GENMASK(7, 4)
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#define MT6370_BL_EXT_EN_MASK BIT(7)
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#define MT6370_BL_EN_MASK BIT(6)
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#define MT6370_BL_CODE_MASK BIT(0)
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#define MT6370_BL_CH_MASK GENMASK(5, 2)
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#define MT6370_BL_CH_SHIFT 2
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#define MT6370_BL_DIM2_COMMON_MASK GENMASK(2, 0)
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#define MT6370_BL_DIM2_COMMON_SHIFT 3
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#define MT6370_BL_DIM2_6372_MASK GENMASK(5, 0)
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#define MT6370_BL_DIM2_6372_SHIFT 6
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#define MT6370_BL_PWM_EN_MASK BIT(7)
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#define MT6370_BL_PWM_HYS_EN_MASK BIT(2)
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#define MT6370_BL_PWM_HYS_SEL_MASK GENMASK(1, 0)
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#define MT6370_BL_OVP_EN_MASK BIT(7)
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#define MT6370_BL_OVP_SEL_MASK GENMASK(6, 5)
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#define MT6370_BL_OVP_SEL_SHIFT 5
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#define MT6370_BL_OC_EN_MASK BIT(3)
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#define MT6370_BL_OC_SEL_MASK GENMASK(2, 1)
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#define MT6370_BL_OC_SEL_SHIFT 1
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#define MT6370_BL_PWM_HYS_TH_MIN_STEP 1
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#define MT6370_BL_PWM_HYS_TH_MAX_STEP 64
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#define MT6370_BL_OVP_MIN_UV 17000000
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#define MT6370_BL_OVP_MAX_UV 29000000
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#define MT6370_BL_OVP_STEP_UV 4000000
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#define MT6370_BL_OCP_MIN_UA 900000
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#define MT6370_BL_OCP_MAX_UA 1800000
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#define MT6370_BL_OCP_STEP_UA 300000
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#define MT6370_BL_MAX_COMMON_BRIGHTNESS 2048
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#define MT6370_BL_MAX_6372_BRIGHTNESS 16384
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#define MT6370_BL_MAX_CH 15
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enum {
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MT6370_VID_COMMON = 1,
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MT6370_VID_6372,
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};
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struct mt6370_priv {
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u8 dim2_mask;
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u8 dim2_shift;
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int def_max_brightness;
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struct backlight_device *bl;
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struct device *dev;
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struct gpio_desc *enable_gpio;
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struct regmap *regmap;
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};
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static int mt6370_bl_update_status(struct backlight_device *bl_dev)
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{
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struct mt6370_priv *priv = bl_get_data(bl_dev);
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int brightness = backlight_get_brightness(bl_dev);
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unsigned int enable_val;
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u8 brightness_val[2];
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int ret;
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if (brightness) {
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brightness_val[0] = (brightness - 1) & priv->dim2_mask;
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brightness_val[1] = (brightness - 1) >> priv->dim2_shift;
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ret = regmap_raw_write(priv->regmap, MT6370_REG_BL_DIM2,
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brightness_val, sizeof(brightness_val));
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if (ret)
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return ret;
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}
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gpiod_set_value(priv->enable_gpio, !!brightness);
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enable_val = brightness ? MT6370_BL_EN_MASK : 0;
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return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN,
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MT6370_BL_EN_MASK, enable_val);
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}
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static int mt6370_bl_get_brightness(struct backlight_device *bl_dev)
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{
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struct mt6370_priv *priv = bl_get_data(bl_dev);
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unsigned int enable;
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u8 brightness_val[2];
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int brightness, ret;
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ret = regmap_read(priv->regmap, MT6370_REG_BL_EN, &enable);
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if (ret)
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return ret;
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if (!(enable & MT6370_BL_EN_MASK))
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return 0;
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ret = regmap_raw_read(priv->regmap, MT6370_REG_BL_DIM2,
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brightness_val, sizeof(brightness_val));
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if (ret)
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return ret;
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brightness = brightness_val[1] << priv->dim2_shift;
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brightness += brightness_val[0] & priv->dim2_mask;
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return brightness + 1;
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}
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static const struct backlight_ops mt6370_bl_ops = {
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.options = BL_CORE_SUSPENDRESUME,
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.update_status = mt6370_bl_update_status,
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.get_brightness = mt6370_bl_get_brightness,
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};
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static int mt6370_init_backlight_properties(struct mt6370_priv *priv,
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struct backlight_properties *props)
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{
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struct device *dev = priv->dev;
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u8 prop_val;
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u32 brightness, ovp_uV, ocp_uA;
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unsigned int mask, val;
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int ret;
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/* Vendor optional properties */
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val = 0;
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if (device_property_read_bool(dev, "mediatek,bled-pwm-enable"))
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val |= MT6370_BL_PWM_EN_MASK;
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if (device_property_read_bool(dev, "mediatek,bled-pwm-hys-enable"))
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val |= MT6370_BL_PWM_HYS_EN_MASK;
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ret = device_property_read_u8(dev,
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"mediatek,bled-pwm-hys-input-th-steps",
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&prop_val);
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if (!ret) {
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prop_val = clamp_val(prop_val,
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MT6370_BL_PWM_HYS_TH_MIN_STEP,
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MT6370_BL_PWM_HYS_TH_MAX_STEP);
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prop_val = prop_val <= 1 ? 0 :
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prop_val <= 4 ? 1 :
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prop_val <= 16 ? 2 : 3;
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val |= prop_val;
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}
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ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_PWM,
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val, val);
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if (ret)
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return ret;
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val = 0;
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if (device_property_read_bool(dev, "mediatek,bled-ovp-shutdown"))
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val |= MT6370_BL_OVP_EN_MASK;
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ret = device_property_read_u32(dev, "mediatek,bled-ovp-microvolt",
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&ovp_uV);
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if (!ret) {
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ovp_uV = clamp_val(ovp_uV, MT6370_BL_OVP_MIN_UV,
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MT6370_BL_OVP_MAX_UV);
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ovp_uV = DIV_ROUND_UP(ovp_uV - MT6370_BL_OVP_MIN_UV,
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MT6370_BL_OVP_STEP_UV);
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val |= ovp_uV << MT6370_BL_OVP_SEL_SHIFT;
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}
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if (device_property_read_bool(dev, "mediatek,bled-ocp-shutdown"))
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val |= MT6370_BL_OC_EN_MASK;
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ret = device_property_read_u32(dev, "mediatek,bled-ocp-microamp",
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&ocp_uA);
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if (!ret) {
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ocp_uA = clamp_val(ocp_uA, MT6370_BL_OCP_MIN_UA,
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MT6370_BL_OCP_MAX_UA);
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ocp_uA = DIV_ROUND_UP(ocp_uA - MT6370_BL_OCP_MIN_UA,
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MT6370_BL_OCP_STEP_UA);
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val |= ocp_uA << MT6370_BL_OC_SEL_SHIFT;
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}
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ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_BSTCTRL,
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val, val);
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if (ret)
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return ret;
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/* Common properties */
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ret = device_property_read_u32(dev, "max-brightness", &brightness);
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if (ret)
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brightness = priv->def_max_brightness;
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props->max_brightness = min_t(u32, brightness, priv->def_max_brightness);
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ret = device_property_read_u32(dev, "default-brightness", &brightness);
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if (ret)
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brightness = props->max_brightness;
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props->brightness = min_t(u32, brightness, props->max_brightness);
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val = 0;
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if (device_property_read_bool(dev, "mediatek,bled-exponential-mode-enable")) {
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val |= MT6370_BL_CODE_MASK;
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props->scale = BACKLIGHT_SCALE_NON_LINEAR;
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} else
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props->scale = BACKLIGHT_SCALE_LINEAR;
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ret = device_property_read_u8(dev, "mediatek,bled-channel-use",
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&prop_val);
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if (ret) {
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dev_err(dev, "mediatek,bled-channel-use DT property missing\n");
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return ret;
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}
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if (!prop_val || prop_val > MT6370_BL_MAX_CH) {
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dev_err(dev,
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"No channel specified or over than upper bound (%d)\n",
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prop_val);
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return -EINVAL;
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}
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mask = MT6370_BL_EXT_EN_MASK | MT6370_BL_CH_MASK;
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val |= prop_val << MT6370_BL_CH_SHIFT;
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if (priv->enable_gpio)
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val |= MT6370_BL_EXT_EN_MASK;
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return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, mask, val);
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}
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static int mt6370_check_vendor_info(struct mt6370_priv *priv)
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{
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/*
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* Because MT6372 uses 14 bits to control the brightness,
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* MT6370 and MT6371 use 11 bits. This function is used
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* to check the vendor's ID and set the relative hardware
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* mask, shift and default maximum brightness value that
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* should be used.
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*/
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unsigned int dev_info, hw_vid, of_vid;
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int ret;
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ret = regmap_read(priv->regmap, MT6370_REG_DEV_INFO, &dev_info);
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if (ret)
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return ret;
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of_vid = (uintptr_t)device_get_match_data(priv->dev);
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hw_vid = FIELD_GET(MT6370_VENID_MASK, dev_info);
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hw_vid = (hw_vid == 0x9 || hw_vid == 0xb) ? MT6370_VID_6372 : MT6370_VID_COMMON;
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if (hw_vid != of_vid)
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return dev_err_probe(priv->dev, -EINVAL,
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"Buggy DT, wrong compatible string\n");
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if (hw_vid == MT6370_VID_6372) {
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priv->dim2_mask = MT6370_BL_DIM2_6372_MASK;
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priv->dim2_shift = MT6370_BL_DIM2_6372_SHIFT;
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priv->def_max_brightness = MT6370_BL_MAX_6372_BRIGHTNESS;
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} else {
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priv->dim2_mask = MT6370_BL_DIM2_COMMON_MASK;
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priv->dim2_shift = MT6370_BL_DIM2_COMMON_SHIFT;
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priv->def_max_brightness = MT6370_BL_MAX_COMMON_BRIGHTNESS;
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}
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return 0;
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}
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static int mt6370_bl_probe(struct platform_device *pdev)
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{
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struct backlight_properties props = {
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.type = BACKLIGHT_RAW,
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};
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struct device *dev = &pdev->dev;
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struct mt6370_priv *priv;
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int ret;
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->dev = dev;
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priv->regmap = dev_get_regmap(dev->parent, NULL);
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if (!priv->regmap)
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return dev_err_probe(dev, -ENODEV, "Failed to get regmap\n");
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ret = mt6370_check_vendor_info(priv);
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if (ret)
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return dev_err_probe(dev, ret, "Failed to check vendor info\n");
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priv->enable_gpio = devm_gpiod_get_optional(dev, "enable",
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GPIOD_OUT_HIGH);
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if (IS_ERR(priv->enable_gpio))
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return dev_err_probe(dev, PTR_ERR(priv->enable_gpio),
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"Failed to get 'enable' gpio\n");
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ret = mt6370_init_backlight_properties(priv, &props);
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if (ret)
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return dev_err_probe(dev, ret,
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"Failed to init backlight properties\n");
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priv->bl = devm_backlight_device_register(dev, pdev->name, dev, priv,
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&mt6370_bl_ops, &props);
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if (IS_ERR(priv->bl))
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return dev_err_probe(dev, PTR_ERR(priv->bl),
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"Failed to register backlight\n");
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backlight_update_status(priv->bl);
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platform_set_drvdata(pdev, priv);
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return 0;
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}
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static int mt6370_bl_remove(struct platform_device *pdev)
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{
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struct mt6370_priv *priv = platform_get_drvdata(pdev);
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struct backlight_device *bl_dev = priv->bl;
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bl_dev->props.brightness = 0;
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backlight_update_status(priv->bl);
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return 0;
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}
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static const struct of_device_id mt6370_bl_of_match[] = {
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{ .compatible = "mediatek,mt6370-backlight", .data = (void *)MT6370_VID_COMMON },
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{ .compatible = "mediatek,mt6372-backlight", .data = (void *)MT6370_VID_6372 },
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{}
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};
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MODULE_DEVICE_TABLE(of, mt6370_bl_of_match);
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static struct platform_driver mt6370_bl_driver = {
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.driver = {
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.name = "mt6370-backlight",
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.of_match_table = mt6370_bl_of_match,
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},
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.probe = mt6370_bl_probe,
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.remove = mt6370_bl_remove,
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};
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module_platform_driver(mt6370_bl_driver);
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MODULE_AUTHOR("ChiaEn Wu <chiaen_wu@richtek.com>");
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MODULE_DESCRIPTION("MediaTek MT6370 Backlight Driver");
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MODULE_LICENSE("GPL v2");
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