[PATCH v4 1/2] backlight: ktz8866: Add support for Kinetic KTZ8866 backlight
From: Jianhua Lu <lujianhua000@gmail.com>
Date: 2023-01-17 13:49:16
Add support for Kinetic KTZ8866 backlight, which is used in Xiaomi tablet, Mi Pad 5 series. This driver lightly based on downstream implementation [1]. [1] https://github.com/MiCode/Xiaomi_Kernel_OpenSource/blob/elish-r-oss/drivers/video/backlight/ktz8866.c Signed-off-by: Jianhua Lu <lujianhua000@gmail.com> --- Changes in v2: - Add missing staitc modifier to ktz8866_write function. Changes in v3: - Add 2022 to Copyright line. - Sort headers. - Remove meaningless comment. - Use definitions instead of hardcoding. - Add missing maintainer info. Changes in v4: - Change 2022 to 2023. - Remove useless macro and enum. - Describe settings by devicetree. - Move header file to C file. MAINTAINERS | 6 + drivers/video/backlight/Kconfig | 8 ++ drivers/video/backlight/Makefile | 1 + drivers/video/backlight/ktz8866.c | 195 ++++++++++++++++++++++++++++++ 4 files changed, 210 insertions(+) create mode 100644 drivers/video/backlight/ktz8866.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 42fc47c6edfd..2084e74e1b58 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS@@ -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
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 936ba1e4d35e..2845fd7e33ad 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig@@ -190,6 +190,14 @@ 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 enabled 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
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index e815f3f1deff..f70a819c304c 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile@@ -36,6 +36,7 @@ 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
diff --git a/drivers/video/backlight/ktz8866.c b/drivers/video/backlight/ktz8866.c
new file mode 100644
index 000000000000..98916f92d069
--- /dev/null
+++ b/drivers/video/backlight/ktz8866.c@@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Backlight driver for the Kinetic KTZ8866 + * + * Copyright (C) 2023 Jianhua Lu <lujianhua000@gmail.com> + */ + +#include <linux/backlight.h> +#include <linux/delay.h> +#include <linux/err.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; +}; + +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; + msleep(10); + } + + /* 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; + + 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 specifed. */ + ktz8866_write(ktz, BL_EN, BIT(6) - 1); + + if(of_property_read_u32(ktz->client->dev.of_node, "current-ramping-time", &val)) + ktz8866_write(ktz, BL_CFG2, BIT(7) | (ilog2(val) << 3) | PWM_HYST); + + if(of_property_read_u32(ktz->client->dev.of_node, "led-ramping-time", &val)) { + 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, "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; + + 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)) { + dev_err(&client->dev, "failed to init regmap\n"); + return PTR_ERR(ktz->regmap); + } + + memset(&props, 0, sizeof(props)); + props.type = BACKLIGHT_RAW; + props.max_brightness = MAX_BRIGHTNESS; + props.brightness = DEFAULT_BRIGHTNESS; + + backlight_dev = devm_backlight_device_register( + &client->dev, "ktz8866-backlight", &client->dev, ktz, + &ktz8866_backlight_ops, &props); + + if (IS_ERR(backlight_dev)) { + dev_err(&client->dev, "failed to register backlight device\n"); + return PTR_ERR(backlight_dev); + } + + 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");
--
2.38.2