On 18/01/2023 14:10, Jianhua Lu wrote: > 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@xxxxxxxxx> > --- > 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. > > Changes in v5: > - Change "2023" to "2022, 2023" in Copyright line. > - Set scale property for backlight. > > Changes in v6: > - Correct devicetree property name. > > MAINTAINERS | 6 + > drivers/video/backlight/Kconfig | 8 ++ > drivers/video/backlight/Makefile | 1 + > drivers/video/backlight/ktz8866.c | 205 ++++++++++++++++++++++++++++++ > 4 files changed, 220 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@xxxxxxxxxxxxxx> > S: Maintained > F: tools/testing/ktest > > +KTZ8866 BACKLIGHT DRIVER > +M: Jianhua Lu <lujianhua000@xxxxxxxxx> > +S: Maintained > +F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml > +F: drivers/video/backlight/ktz8866.c > + > L3MDEV > M: David Ahern <dsahern@xxxxxxxxxx> > L: netdev@xxxxxxxxxxxxxxx > diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig > index 936ba1e4d35e..f7113ceb264a 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 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 > 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..ca3ac349cd10 > --- /dev/null > +++ b/drivers/video/backlight/ktz8866.c > @@ -0,0 +1,205 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Backlight driver for the Kinetic KTZ8866 > + * > + * Copyright (C) 2022, 2023 Jianhua Lu <lujianhua000@xxxxxxxxx> > + */ > + > +#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); Why 10 ms? Document magic values. Their need, reason behind. > + } > + > + /* 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)) Here and in other places - not conforming to coding style. Missing space before (. Be sure you run checkpatch --strict and fix all relevant errors. > + 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-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, "led-ramping-time-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, "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); > + Drop blank line > + if (IS_ERR(ktz->regmap)) { > + dev_err(&client->dev, "failed to init regmap\n"); dev_err_probe > + return PTR_ERR(ktz->regmap); > + } > + > + 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); > + Drop blank line > + if (IS_ERR(backlight_dev)) { > + dev_err(&client->dev, "failed to register backlight device\n"); dev_err_probe > + 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@xxxxxxxxx>"); > +MODULE_LICENSE("GPL"); Best regards, Krzysztof
