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backlight: ktz8866: Add support for Kinetic KTZ8866 backlight 

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>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230120155018.15376-2-lujianhua000@gmail.com
This commit is contained in:
Jianhua Lu 2023-01-20 23:50:18 +08:00 committed by Lee Jones
parent c8990c3889
commit f8449c8f73
4 changed files with 224 additions and 0 deletions
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6
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

8
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

1
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

209
drivers/video/backlight/ktz8866.c Normal file
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@ -0,0 +1,209 @@
// 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");