diff options
Diffstat (limited to 'drivers/video/backlight/mt6370-backlight.c')
| -rw-r--r-- | drivers/video/backlight/mt6370-backlight.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/drivers/video/backlight/mt6370-backlight.c b/drivers/video/backlight/mt6370-backlight.c new file mode 100644 index 0000000000..94422c9564 --- /dev/null +++ b/drivers/video/backlight/mt6370-backlight.c @@ -0,0 +1,349 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022 Richtek Technology Corp. + * + * Author: ChiaEn Wu <chiaen_wu@richtek.com> + */ + +#include <linux/backlight.h> +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/gpio/consumer.h> +#include <linux/kernel.h> +#include <linux/minmax.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/regmap.h> + +#define MT6370_REG_DEV_INFO 0x100 +#define MT6370_REG_BL_EN 0x1A0 +#define MT6370_REG_BL_BSTCTRL 0x1A1 +#define MT6370_REG_BL_PWM 0x1A2 +#define MT6370_REG_BL_DIM2 0x1A4 + +#define MT6370_VENID_MASK GENMASK(7, 4) +#define MT6370_BL_EXT_EN_MASK BIT(7) +#define MT6370_BL_EN_MASK BIT(6) +#define MT6370_BL_CODE_MASK BIT(0) +#define MT6370_BL_CH_MASK GENMASK(5, 2) +#define MT6370_BL_CH_SHIFT 2 +#define MT6370_BL_DIM2_COMMON_MASK GENMASK(2, 0) +#define MT6370_BL_DIM2_COMMON_SHIFT 3 +#define MT6370_BL_DIM2_6372_MASK GENMASK(5, 0) +#define MT6370_BL_DIM2_6372_SHIFT 6 +#define MT6370_BL_PWM_EN_MASK BIT(7) +#define MT6370_BL_PWM_HYS_EN_MASK BIT(2) +#define MT6370_BL_PWM_HYS_SEL_MASK GENMASK(1, 0) +#define MT6370_BL_OVP_EN_MASK BIT(7) +#define MT6370_BL_OVP_SEL_MASK GENMASK(6, 5) +#define MT6370_BL_OVP_SEL_SHIFT 5 +#define MT6370_BL_OC_EN_MASK BIT(3) +#define MT6370_BL_OC_SEL_MASK GENMASK(2, 1) +#define MT6370_BL_OC_SEL_SHIFT 1 + +#define MT6370_BL_PWM_HYS_TH_MIN_STEP 1 +#define MT6370_BL_PWM_HYS_TH_MAX_STEP 64 +#define MT6370_BL_OVP_MIN_UV 17000000 +#define MT6370_BL_OVP_MAX_UV 29000000 +#define MT6370_BL_OVP_STEP_UV 4000000 +#define MT6370_BL_OCP_MIN_UA 900000 +#define MT6370_BL_OCP_MAX_UA 1800000 +#define MT6370_BL_OCP_STEP_UA 300000 +#define MT6370_BL_MAX_COMMON_BRIGHTNESS 2048 +#define MT6370_BL_MAX_6372_BRIGHTNESS 16384 +#define MT6370_BL_MAX_CH 15 + +enum { + MT6370_VID_COMMON = 1, + MT6370_VID_6372, +}; + +struct mt6370_priv { + u8 dim2_mask; + u8 dim2_shift; + int def_max_brightness; + struct backlight_device *bl; + struct device *dev; + struct gpio_desc *enable_gpio; + struct regmap *regmap; +}; + +static int mt6370_bl_update_status(struct backlight_device *bl_dev) +{ + struct mt6370_priv *priv = bl_get_data(bl_dev); + int brightness = backlight_get_brightness(bl_dev); + unsigned int enable_val; + u8 brightness_val[2]; + int ret; + + if (brightness) { + brightness_val[0] = (brightness - 1) & priv->dim2_mask; + brightness_val[1] = (brightness - 1) >> priv->dim2_shift; + + ret = regmap_raw_write(priv->regmap, MT6370_REG_BL_DIM2, + brightness_val, sizeof(brightness_val)); + if (ret) + return ret; + } + + gpiod_set_value(priv->enable_gpio, !!brightness); + + enable_val = brightness ? MT6370_BL_EN_MASK : 0; + return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, + MT6370_BL_EN_MASK, enable_val); +} + +static int mt6370_bl_get_brightness(struct backlight_device *bl_dev) +{ + struct mt6370_priv *priv = bl_get_data(bl_dev); + unsigned int enable; + u8 brightness_val[2]; + int brightness, ret; + + ret = regmap_read(priv->regmap, MT6370_REG_BL_EN, &enable); + if (ret) + return ret; + + if (!(enable & MT6370_BL_EN_MASK)) + return 0; + + ret = regmap_raw_read(priv->regmap, MT6370_REG_BL_DIM2, + brightness_val, sizeof(brightness_val)); + if (ret) + return ret; + + brightness = brightness_val[1] << priv->dim2_shift; + brightness += brightness_val[0] & priv->dim2_mask; + + return brightness + 1; +} + +static const struct backlight_ops mt6370_bl_ops = { + .options = BL_CORE_SUSPENDRESUME, + .update_status = mt6370_bl_update_status, + .get_brightness = mt6370_bl_get_brightness, +}; + +static int mt6370_init_backlight_properties(struct mt6370_priv *priv, + struct backlight_properties *props) +{ + struct device *dev = priv->dev; + u8 prop_val; + u32 brightness, ovp_uV, ocp_uA; + unsigned int mask, val; + int ret; + + /* Vendor optional properties */ + val = 0; + if (device_property_read_bool(dev, "mediatek,bled-pwm-enable")) + val |= MT6370_BL_PWM_EN_MASK; + + if (device_property_read_bool(dev, "mediatek,bled-pwm-hys-enable")) + val |= MT6370_BL_PWM_HYS_EN_MASK; + + ret = device_property_read_u8(dev, + "mediatek,bled-pwm-hys-input-th-steps", + &prop_val); + if (!ret) { + prop_val = clamp_val(prop_val, + MT6370_BL_PWM_HYS_TH_MIN_STEP, + MT6370_BL_PWM_HYS_TH_MAX_STEP); + prop_val = prop_val <= 1 ? 0 : + prop_val <= 4 ? 1 : + prop_val <= 16 ? 2 : 3; + val |= prop_val; + } + + ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_PWM, + val, val); + if (ret) + return ret; + + val = 0; + if (device_property_read_bool(dev, "mediatek,bled-ovp-shutdown")) + val |= MT6370_BL_OVP_EN_MASK; + + ret = device_property_read_u32(dev, "mediatek,bled-ovp-microvolt", + &ovp_uV); + if (!ret) { + ovp_uV = clamp_val(ovp_uV, MT6370_BL_OVP_MIN_UV, + MT6370_BL_OVP_MAX_UV); + ovp_uV = DIV_ROUND_UP(ovp_uV - MT6370_BL_OVP_MIN_UV, + MT6370_BL_OVP_STEP_UV); + val |= ovp_uV << MT6370_BL_OVP_SEL_SHIFT; + } + + if (device_property_read_bool(dev, "mediatek,bled-ocp-shutdown")) + val |= MT6370_BL_OC_EN_MASK; + + ret = device_property_read_u32(dev, "mediatek,bled-ocp-microamp", + &ocp_uA); + if (!ret) { + ocp_uA = clamp_val(ocp_uA, MT6370_BL_OCP_MIN_UA, + MT6370_BL_OCP_MAX_UA); + ocp_uA = DIV_ROUND_UP(ocp_uA - MT6370_BL_OCP_MIN_UA, + MT6370_BL_OCP_STEP_UA); + val |= ocp_uA << MT6370_BL_OC_SEL_SHIFT; + } + + ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_BSTCTRL, + val, val); + if (ret) + return ret; + + /* Common properties */ + ret = device_property_read_u32(dev, "max-brightness", &brightness); + if (ret) + brightness = priv->def_max_brightness; + + props->max_brightness = min_t(u32, brightness, priv->def_max_brightness); + + ret = device_property_read_u32(dev, "default-brightness", &brightness); + if (ret) + brightness = props->max_brightness; + + props->brightness = min_t(u32, brightness, props->max_brightness); + + val = 0; + if (device_property_read_bool(dev, "mediatek,bled-exponential-mode-enable")) { + val |= MT6370_BL_CODE_MASK; + props->scale = BACKLIGHT_SCALE_NON_LINEAR; + } else + props->scale = BACKLIGHT_SCALE_LINEAR; + + ret = device_property_read_u8(dev, "mediatek,bled-channel-use", + &prop_val); + if (ret) { + dev_err(dev, "mediatek,bled-channel-use DT property missing\n"); + return ret; + } + + if (!prop_val || prop_val > MT6370_BL_MAX_CH) { + dev_err(dev, + "No channel specified or over than upper bound (%d)\n", + prop_val); + return -EINVAL; + } + + mask = MT6370_BL_EXT_EN_MASK | MT6370_BL_CH_MASK; + val |= prop_val << MT6370_BL_CH_SHIFT; + + if (priv->enable_gpio) + val |= MT6370_BL_EXT_EN_MASK; + + return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, mask, val); +} + +static int mt6370_check_vendor_info(struct mt6370_priv *priv) +{ + /* + * Because MT6372 uses 14 bits to control the brightness, + * MT6370 and MT6371 use 11 bits. This function is used + * to check the vendor's ID and set the relative hardware + * mask, shift and default maximum brightness value that + * should be used. + */ + unsigned int dev_info, hw_vid, of_vid; + int ret; + + ret = regmap_read(priv->regmap, MT6370_REG_DEV_INFO, &dev_info); + if (ret) + return ret; + + of_vid = (uintptr_t)device_get_match_data(priv->dev); + hw_vid = FIELD_GET(MT6370_VENID_MASK, dev_info); + hw_vid = (hw_vid == 0x9 || hw_vid == 0xb) ? MT6370_VID_6372 : MT6370_VID_COMMON; + if (hw_vid != of_vid) + return dev_err_probe(priv->dev, -EINVAL, + "Buggy DT, wrong compatible string\n"); + + if (hw_vid == MT6370_VID_6372) { + priv->dim2_mask = MT6370_BL_DIM2_6372_MASK; + priv->dim2_shift = MT6370_BL_DIM2_6372_SHIFT; + priv->def_max_brightness = MT6370_BL_MAX_6372_BRIGHTNESS; + } else { + priv->dim2_mask = MT6370_BL_DIM2_COMMON_MASK; + priv->dim2_shift = MT6370_BL_DIM2_COMMON_SHIFT; + priv->def_max_brightness = MT6370_BL_MAX_COMMON_BRIGHTNESS; + } + + return 0; +} + +static int mt6370_bl_probe(struct platform_device *pdev) +{ + struct backlight_properties props = { + .type = BACKLIGHT_RAW, + }; + struct device *dev = &pdev->dev; + struct mt6370_priv *priv; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = dev; + + priv->regmap = dev_get_regmap(dev->parent, NULL); + if (!priv->regmap) + return dev_err_probe(dev, -ENODEV, "Failed to get regmap\n"); + + ret = mt6370_check_vendor_info(priv); + if (ret) + return dev_err_probe(dev, ret, "Failed to check vendor info\n"); + + priv->enable_gpio = devm_gpiod_get_optional(dev, "enable", + GPIOD_OUT_HIGH); + if (IS_ERR(priv->enable_gpio)) + return dev_err_probe(dev, PTR_ERR(priv->enable_gpio), + "Failed to get 'enable' gpio\n"); + + ret = mt6370_init_backlight_properties(priv, &props); + if (ret) + return dev_err_probe(dev, ret, + "Failed to init backlight properties\n"); + + priv->bl = devm_backlight_device_register(dev, pdev->name, dev, priv, + &mt6370_bl_ops, &props); + if (IS_ERR(priv->bl)) + return dev_err_probe(dev, PTR_ERR(priv->bl), + "Failed to register backlight\n"); + + backlight_update_status(priv->bl); + platform_set_drvdata(pdev, priv); + + return 0; +} + +static void mt6370_bl_remove(struct platform_device *pdev) +{ + struct mt6370_priv *priv = platform_get_drvdata(pdev); + struct backlight_device *bl_dev = priv->bl; + + bl_dev->props.brightness = 0; + backlight_update_status(priv->bl); +} + +static const struct of_device_id mt6370_bl_of_match[] = { + { .compatible = "mediatek,mt6370-backlight", .data = (void *)MT6370_VID_COMMON }, + { .compatible = "mediatek,mt6372-backlight", .data = (void *)MT6370_VID_6372 }, + {} +}; +MODULE_DEVICE_TABLE(of, mt6370_bl_of_match); + +static struct platform_driver mt6370_bl_driver = { + .driver = { + .name = "mt6370-backlight", + .of_match_table = mt6370_bl_of_match, + }, + .probe = mt6370_bl_probe, + .remove_new = mt6370_bl_remove, +}; +module_platform_driver(mt6370_bl_driver); + +MODULE_AUTHOR("ChiaEn Wu <chiaen_wu@richtek.com>"); +MODULE_DESCRIPTION("MediaTek MT6370 Backlight Driver"); +MODULE_LICENSE("GPL v2"); |