backlight: ktz8866: Add support for Kinetic KTZ8866 backlight (f8449c8f) · Commits · EulixOS / Software / Kernel

MAINTAINERS

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		@@ -11674,6 +11674,12 @@ M: John Hawley <warthog9@eaglescrag.net>
		S: Maintained
		F: tools/testing/ktest

		KTZ8866 BACKLIGHT DRIVER
		M: Jianhua Lu <lujianhua000@gmail.com>
		S: Maintained
		F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
		F: drivers/video/backlight/ktz8866.c

		L3MDEV
		M: David Ahern <dsahern@kernel.org>
		L: netdev@vger.kernel.org

drivers/video/backlight/Kconfig

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		@@ -183,6 +183,14 @@ config BACKLIGHT_KTD253
		which is a 1-wire GPIO-controlled backlight found in some mobile
		phones.

		config BACKLIGHT_KTZ8866
		tristate "Backlight Driver for Kinetic KTZ8866"
		depends on I2C
		select REGMAP_I2C
		help
		Say Y to enable the backlight driver for the Kinetic KTZ8866
		found in Xiaomi Mi Pad 5 series.

		config BACKLIGHT_LM3533
		tristate "Backlight Driver for LM3533"
		depends on MFD_LM3533

drivers/video/backlight/Makefile

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		@@ -35,6 +35,7 @@ obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
		obj-$(CONFIG_BACKLIGHT_HP700) += jornada720_bl.o
		obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO) += ipaq_micro_bl.o
		obj-$(CONFIG_BACKLIGHT_KTD253) += ktd253-backlight.o
		obj-$(CONFIG_BACKLIGHT_KTZ8866) += ktz8866.o
		obj-$(CONFIG_BACKLIGHT_LM3533) += lm3533_bl.o
		obj-$(CONFIG_BACKLIGHT_LM3630A) += lm3630a_bl.o
		obj-$(CONFIG_BACKLIGHT_LM3639) += lm3639_bl.o

drivers/video/backlight/ktz8866.c

0 → 100644

+209 −0

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		// SPDX-License-Identifier: GPL-2.0-only
		/*
		* Backlight driver for the Kinetic KTZ8866
		*
		* Copyright (C) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>
		*/

		#include <linux/backlight.h>
		#include <linux/err.h>
		#include <linux/gpio/consumer.h>
		#include <linux/i2c.h>
		#include <linux/module.h>
		#include <linux/of.h>
		#include <linux/regmap.h>

		#define DEFAULT_BRIGHTNESS 1500
		#define MAX_BRIGHTNESS 2047
		#define REG_MAX 0x15

		/* reg */
		#define DEVICE_ID 0x01
		#define BL_CFG1 0x02
		#define BL_CFG2 0x03
		#define BL_BRT_LSB 0x04
		#define BL_BRT_MSB 0x05
		#define BL_EN 0x08
		#define LCD_BIAS_CFG1 0x09
		#define LCD_BIAS_CFG2 0x0A
		#define LCD_BIAS_CFG3 0x0B
		#define LCD_BOOST_CFG 0x0C
		#define OUTP_CFG 0x0D
		#define OUTN_CFG 0x0E
		#define FLAG 0x0F
		#define BL_OPTION1 0x10
		#define BL_OPTION2 0x11
		#define PWM2DIG_LSBs 0x12
		#define PWM2DIG_MSBs 0x13
		#define BL_DIMMING 0x14
		#define PWM_RAMP_TIME 0x15

		/* definition */
		#define BL_EN_BIT BIT(6)
		#define LCD_BIAS_EN 0x9F
		#define PWM_HYST 0x5

		struct ktz8866 {
		struct i2c_client *client;
		struct regmap *regmap;
		bool led_on;
		struct gpio_desc *enable_gpio;
		};

		static const struct regmap_config ktz8866_regmap_config = {
		.reg_bits = 8,
		.val_bits = 8,
		.max_register = REG_MAX,
		};

		static int ktz8866_write(struct ktz8866 *ktz, unsigned int reg,
		unsigned int val)
		{
		return regmap_write(ktz->regmap, reg, val);
		}

		static int ktz8866_update_bits(struct ktz8866 *ktz, unsigned int reg,
		unsigned int mask, unsigned int val)
		{
		return regmap_update_bits(ktz->regmap, reg, mask, val);
		}

		static int ktz8866_backlight_update_status(struct backlight_device *backlight_dev)
		{
		struct ktz8866 *ktz = bl_get_data(backlight_dev);
		unsigned int brightness = backlight_get_brightness(backlight_dev);

		if (!ktz->led_on && brightness > 0) {
		ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, BL_EN_BIT);
		ktz->led_on = true;
		} else if (brightness == 0) {
		ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, 0);
		ktz->led_on = false;
		}

		/* Set brightness */
		ktz8866_write(ktz, BL_BRT_LSB, brightness & 0x7);
		ktz8866_write(ktz, BL_BRT_MSB, (brightness >> 3) & 0xFF);

		return 0;
		}

		static const struct backlight_ops ktz8866_backlight_ops = {
		.options = BL_CORE_SUSPENDRESUME,
		.update_status = ktz8866_backlight_update_status,
		};

		static void ktz8866_init(struct ktz8866 *ktz)
		{
		unsigned int val = 0;

		if (of_property_read_u32(ktz->client->dev.of_node, "current-num-sinks", &val))
		ktz8866_write(ktz, BL_EN, BIT(val) - 1);
		else
		/* Enable all 6 current sinks if the number of current sinks isn't specified. */
		ktz8866_write(ktz, BL_EN, BIT(6) - 1);

		if (of_property_read_u32(ktz->client->dev.of_node, "kinetic,current-ramp-delay-ms", &val)) {
		if (val <= 128)
		ktz8866_write(ktz, BL_CFG2, BIT(7) \| (ilog2(val) << 3) \| PWM_HYST);
		else
		ktz8866_write(ktz, BL_CFG2, BIT(7) \| ((5 + val / 64) << 3) \| PWM_HYST);
		}

		if (of_property_read_u32(ktz->client->dev.of_node, "kinetic,led-enable-ramp-delay-ms", &val)) {
		if (val == 0)
		ktz8866_write(ktz, BL_DIMMING, 0);
		else {
		unsigned int ramp_off_time = ilog2(val) + 1;
		unsigned int ramp_on_time = ramp_off_time << 4;
		ktz8866_write(ktz, BL_DIMMING, ramp_on_time \| ramp_off_time);
		}
		}

		if (of_property_read_bool(ktz->client->dev.of_node, "kinetic,enable-lcd-bias"))
		ktz8866_write(ktz, LCD_BIAS_CFG1, LCD_BIAS_EN);
		}

		static int ktz8866_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
		{
		struct backlight_device *backlight_dev;
		struct backlight_properties props;
		struct ktz8866 *ktz;
		int ret = 0;

		ktz = devm_kzalloc(&client->dev, sizeof(*ktz), GFP_KERNEL);
		if (!ktz)
		return -ENOMEM;

		ktz->client = client;
		ktz->regmap = devm_regmap_init_i2c(client, &ktz8866_regmap_config);
		if (IS_ERR(ktz->regmap))
		return dev_err_probe(&client->dev, PTR_ERR(ktz->regmap), "failed to init regmap\n");

		ret = devm_regulator_get_enable(&client->dev, "vddpos");
		if (ret)
		return dev_err_probe(&client->dev, ret, "get regulator vddpos failed\n");
		ret = devm_regulator_get_enable(&client->dev, "vddneg");
		if (ret)
		return dev_err_probe(&client->dev, ret, "get regulator vddneg failed\n");

		ktz->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
		if (IS_ERR(ktz->enable_gpio))
		return PTR_ERR(ktz->enable_gpio);

		memset(&props, 0, sizeof(props));
		props.type = BACKLIGHT_RAW;
		props.max_brightness = MAX_BRIGHTNESS;
		props.brightness = DEFAULT_BRIGHTNESS;
		props.scale = BACKLIGHT_SCALE_LINEAR;

		backlight_dev = devm_backlight_device_register(&client->dev, "ktz8866-backlight",
		&client->dev, ktz, &ktz8866_backlight_ops, &props);
		if (IS_ERR(backlight_dev))
		return dev_err_probe(&client->dev, PTR_ERR(backlight_dev),
		"failed to register backlight device\n");

		ktz8866_init(ktz);

		i2c_set_clientdata(client, backlight_dev);
		backlight_update_status(backlight_dev);

		return 0;
		}

		static void ktz8866_remove(struct i2c_client *client)
		{
		struct backlight_device *backlight_dev = i2c_get_clientdata(client);
		backlight_dev->props.brightness = 0;
		backlight_update_status(backlight_dev);
		}

		static const struct i2c_device_id ktz8866_ids[] = {
		{ "ktz8866", 0 },
		{},
		};
		MODULE_DEVICE_TABLE(i2c, ktz8866_ids);

		static const struct of_device_id ktz8866_match_table[] = {
		{
		.compatible = "kinetic,ktz8866",
		},
		{},
		};

		static struct i2c_driver ktz8866_driver = {
		.driver = {
		.name = "ktz8866",
		.of_match_table = ktz8866_match_table,
		},
		.probe = ktz8866_probe,
		.remove = ktz8866_remove,
		.id_table = ktz8866_ids,
		};

		module_i2c_driver(ktz8866_driver);

		MODULE_DESCRIPTION("Kinetic KTZ8866 Backlight Driver");
		MODULE_AUTHOR("Jianhua Lu <lujianhua000@gmail.com>");
		MODULE_LICENSE("GPL");