Commit a47e6072 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'backlight-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight 

Pull backlight update from Lee Jones:

 - Add support for MediaTek MT6370 Backlight

* tag 'backlight-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  video: backlight: mt6370: Add MediaTek MT6370 support
  dt-bindings: backlight: Add MediaTek MT6370 backlight
parents 7fb68b6c e7647de0

Documentation/devicetree/bindings/leds/backlight/mediatek,mt6370-backlight.yaml

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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/leds/backlight/mediatek,mt6370-backlight.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#



title: MediaTek MT6370 Backlight



maintainers:

  - ChiaEn Wu <chiaen_wu@richtek.com>



description: |

  This module is part of the MT6370 MFD device.

  The MT6370 Backlight WLED driver supports up to a 29V output voltage for

  4 channels of 8 series WLEDs. Each channel supports up to 30mA of current

  capability with 2048 current steps (11 bits, only for MT6370/MT6371) or

  16384 current steps (14 bits, only for MT6372) in exponential or linear

  mapping curves.



allOf:

  - $ref: common.yaml#



properties:

  compatible:

    enum:

      - mediatek,mt6370-backlight

      - mediatek,mt6372-backlight



  default-brightness:

    minimum: 0



  max-brightness:

    minimum: 0



  enable-gpios:

    description: External backlight 'enable' pin

    maxItems: 1



  mediatek,bled-pwm-enable:

    description: |

      Enable external PWM input for backlight dimming

    type: boolean



  mediatek,bled-pwm-hys-enable:

    description: |

      Enable the backlight input-hysteresis for PWM mode

    type: boolean



  mediatek,bled-pwm-hys-input-th-steps:

    $ref: /schemas/types.yaml#/definitions/uint8

    enum: [1, 4, 16, 64]

    description: |

      The selection of the upper and lower bounds threshold of backlight

      PWM resolution. If we choose selection 64, the variation of PWM

      resolution needs more than 64 steps.



  mediatek,bled-ovp-shutdown:

    description: |

      Enable the backlight shutdown when OVP level triggered

    type: boolean



  mediatek,bled-ovp-microvolt:

    enum: [17000000, 21000000, 25000000, 29000000]

    description: |

      Backlight OVP level selection.



  mediatek,bled-ocp-shutdown:

    description: |

      Enable the backlight shutdown when OCP level triggerred.

    type: boolean



  mediatek,bled-ocp-microamp:

    enum: [900000, 1200000, 1500000, 1800000]

    description: |

      Backlight OC level selection.



  mediatek,bled-exponential-mode-enable:

    description: |

      Enable the exponential mode of backlight brightness. If this property

      is not enabled, the default is to use linear mode.

    type: boolean



  mediatek,bled-channel-use:

    $ref: /schemas/types.yaml#/definitions/uint8

    description: |

      Backlight LED channel to be used.

      Each bit mapping to:

        - 0: CH4

        - 1: CH3

        - 2: CH2

        - 3: CH1

    minimum: 1

    maximum: 15



if:

  properties:

    compatible:

      contains:

        const: mediatek,mt6372-backlight



then:

  properties:

    default-brightness:

      maximum: 16384



    max-brightness:

      maximum: 16384



else:

  properties:

    default-brightness:

      maximum: 2048



    max-brightness:

      maximum: 2048



required:

  - compatible

  - mediatek,bled-channel-use



additionalProperties: false

drivers/video/backlight/Kconfig

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@@ -268,6 +268,19 @@ config BACKLIGHT_MAX8925 
	  If you have a LCD backlight connected to the WLED output of MAX8925

	  WLED output, say Y here to enable this driver.



config BACKLIGHT_MT6370

	tristate "MediaTek MT6370 Backlight Driver"

	depends on MFD_MT6370

	help

	  This enables support for Mediatek MT6370 Backlight driver.

	  It's commonly used to drive the display WLED. There are 4 channels

	  inside, and each channel supports up to 30mA of current capability

	  with 2048 current steps (only for MT6370/MT6371) or 16384 current

	  steps (only for MT6372) in exponential or linear mapping curves.



	  This driver can also be built as a module. If so, the module

	  will be called "mt6370-backlight".



config BACKLIGHT_APPLE

	tristate "Apple Backlight Driver"

	depends on X86 && ACPI

drivers/video/backlight/Makefile

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@@ -44,6 +44,7 @@ obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o 
obj-$(CONFIG_BACKLIGHT_LP8788)		+= lp8788_bl.o

obj-$(CONFIG_BACKLIGHT_LV5207LP)	+= lv5207lp.o

obj-$(CONFIG_BACKLIGHT_MAX8925)		+= max8925_bl.o

obj-$(CONFIG_BACKLIGHT_MT6370)		+= mt6370-backlight.o

obj-$(CONFIG_BACKLIGHT_OMAP1)		+= omap1_bl.o

obj-$(CONFIG_BACKLIGHT_PANDORA)		+= pandora_bl.o

obj-$(CONFIG_BACKLIGHT_PCF50633)	+= pcf50633-backlight.o

drivers/video/backlight/mt6370-backlight.c

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// 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 int 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);



	return 0;

}



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 = 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");