diff mbox series

[v4,1/2] backlight: ktz8866: Add support for Kinetic KTZ8866 backlight

Message ID 20230117134742.23238-1-lujianhua000@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v4,1/2] backlight: ktz8866: Add support for Kinetic KTZ8866 backlight | expand

Commit Message

Jianhua Lu Jan. 17, 2023, 1:47 p.m. UTC
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

Comments

Jianhua Lu Jan. 17, 2023, 2:12 p.m. UTC | #1
On Tue, Jan 17, 2023 at 02:04:05PM +0000, Daniel Thompson wrote:
> On Tue, Jan 17, 2023 at 09:47:41PM +0800, 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@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>
> 
> Shouldn't this be:
> Copyright (C) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>
> 
> > +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;
> 
> There is still pending feedback from v3.
> 
> | Please set the scale property correctly. "Unknown" is never correct for
> | new drivers.
Do you means backlight_properties.backlight_scale?
> 
> Do not ignore feedback. You should either act on it or, if you disagree
> or need additional clarification then, reply on the mail thread.
> 
> 
> Daniel.
Jianhua Lu Jan. 17, 2023, 2:27 p.m. UTC | #2
On Tue, Jan 17, 2023 at 02:22:04PM +0000, Daniel Thompson wrote:
> On Tue, Jan 17, 2023 at 09:47:42PM +0800, Jianhua Lu wrote:
> > Add Kinetic KTZ8866 backlight binding documentation.
> >
> > Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
> 
> Might be a good idea to take a look at this bit of the docs because
> the patchset is not in the right order (I.5):
> https://docs.kernel.org/devicetree/bindings/submitting-patches.html
Thanks, I will read it.
> 
> 
> > ---
> > Changes in v2:
> >   - Remove "items" between "compatible" and "const: kinetic,ktz8866"
> >   - Change "additionalProperties" to "unevaluatedProperties"
> >
> > Changes in v3:
> >   - Add Krzysztof's R-b
> >
> > Changes in v4:
> >   - Drop Krzysztof's R-b
> >   - Add some new properties
> >
> >  .../leds/backlight/kinetic,ktz8866.yaml       | 54 +++++++++++++++++++
> >  1 file changed, 54 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> > new file mode 100644
> > index 000000000000..18571d69accb
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> > @@ -0,0 +1,54 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/leds/backlight/kinetic,ktz8866.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Kinetic Technologies KTZ8866 backlight
> > +
> > +maintainers:
> > +  - Jianhua Lu <lujianhua000@gmail.com>
> > +
> > +description: |
> > +  The Kinetic Technologies KTZ8866 is a high efficiency 6-sinks led backlight
> > +  with dual lcd bias power.
> > +  https://www.kinet-ic.com/ktz8866/
> > +
> > +allOf:
> > +  - $ref: common.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    const: kinetic,ktz8866
> > +
> > +  current-num-sinks:
> > +    description: Number of LED current sinks.
> > +
> > +  current-ramping-time:
> > +    description: LED current ramping time.
> 
> Needs to document know what units this value is expressed in. IIRC
> this should be expressed in SI units and included the property name.
> Something like:
> 
>   current-ramping-time-us:
>     description: LED current ramping time in microseconds.
> 
Get it, I will send a new version patch.
> 
> > +
> > +  led-ramping-time:
> > +    description: LED on/off ramping time.
> 
> +1
> 
> 
> Daniel.
Jianhua Lu Jan. 17, 2023, 2:40 p.m. UTC | #3
On Tue, Jan 17, 2023 at 02:37:07PM +0000, Daniel Thompson wrote:
> On Tue, Jan 17, 2023 at 10:12:18PM +0800, Jianhua Lu wrote:
> > On Tue, Jan 17, 2023 at 02:04:05PM +0000, Daniel Thompson wrote:
> > > On Tue, Jan 17, 2023 at 09:47:41PM +0800, 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@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>
> > >
> > > Shouldn't this be:
> > > Copyright (C) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>
> > >
> > > > +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;
> > >
> > > There is still pending feedback from v3.
> > >
> > > | Please set the scale property correctly. "Unknown" is never correct for
> > > | new drivers.
> > Do you means backlight_properties.backlight_scale?
> 
> props.scale = BACKLIGHT_SCALE_<whatever_is_correct_for_this_hardware>;
> 
> (the memset means you are currently setting the scale to
> BACKLIGHT_SCALE_UNKNOWN )
Thanks for explanation.
> 
> 
> Daniel.
diff mbox series

Patch

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");