Add Kinetic KTZ8866 backlight binding documentation.
Signed-off-by: Jianhua Lu <[email protected]>
---
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
Changes in v5:
- Add missing enum under property description.
- Rename uncorrect properties.
.../leds/backlight/kinetic,ktz8866.yaml | 57 +++++++++++++++++++
1 file changed, 57 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..1efc29b0632f
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
@@ -0,0 +1,57 @@
+# 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 <[email protected]>
+
+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.
+ enum: [1, 2, 3, 4, 5, 6]
+
+ current-ramping-time-us:
+ description: LED current ramping time in microseconds.
+ enum: [2, 4, 8, 16, 32, 64, 128, 192, 256, 320, 384, 448, 512, 576, 640]
+
+ led-ramping-time-us:
+ description: LED on/off ramping time in microseconds.
+ enum: [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384]
+
+ enable-lcd-bias:
+ description: Set if we want to output bias power supply for LCD.
+ type: boolean
+
+required:
+ - compatible
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ backlight {
+ compatible = "kinetic,ktz8866";
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&bl_en_default>;
+
+ current-num-sinks = <5>;
+ current-ramping-time-us = <128>;
+ led-ramping-time-us = <1>;
+ enable-lcd-bias;
+ };
--
2.38.2
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 <[email protected]>
---
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.
MAINTAINERS | 6 +
drivers/video/backlight/Kconfig | 8 ++
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/ktz8866.c | 201 ++++++++++++++++++++++++++++++
4 files changed, 216 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 <[email protected]>
S: Maintained
F: tools/testing/ktest
+KTZ8866 BACKLIGHT DRIVER
+M: Jianhua Lu <[email protected]>
+S: Maintained
+F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
+F: drivers/video/backlight/ktz8866.c
+
L3MDEV
M: David Ahern <[email protected]>
L: [email protected]
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..02d9be6e9df2
--- /dev/null
+++ b/drivers/video/backlight/ktz8866.c
@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Backlight driver for the Kinetic KTZ8866
+ *
+ * Copyright (C) 2022, 2023 Jianhua Lu <[email protected]>
+ */
+
+#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-us", &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-us", &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;
+ 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)) {
+ 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 <[email protected]>");
+MODULE_LICENSE("GPL");
--
2.38.2
On Tue, Jan 17, 2023 at 11:44:08PM +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 <[email protected]>
> ---
> 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.
>
> MAINTAINERS | 6 +
> drivers/video/backlight/Kconfig | 8 ++
> drivers/video/backlight/Makefile | 1 +
> drivers/video/backlight/ktz8866.c | 201 ++++++++++++++++++++++++++++++
> 4 files changed, 216 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 <[email protected]>
> S: Maintained
> F: tools/testing/ktest
>
> +KTZ8866 BACKLIGHT DRIVER
> +M: Jianhua Lu <[email protected]>
> +S: Maintained
> +F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> +F: drivers/video/backlight/ktz8866.c
> +
> L3MDEV
> M: David Ahern <[email protected]>
> L: [email protected]
> 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.
s/enabled/enable/ (and sorry for spotting this one so late)
> +++ b/drivers/video/backlight/ktz8866.c
> @@ -0,0 +1,201 @@
> [...]
> +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-us", &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);
> + }
This code is interpreting current-ramping-time-us as milliseconds rather
than microseconds!
I know I used microseconds in the example I proposed in the feedback for
v4 DT bindings but "something like" means I am merely providing an
example (mostly I was intending to show that the units should be
included both in the property name *and* description).
It is up to you whether you fix the mismatch by changing the DT bindings
document to current-ramping-time-ms or change this code to accept
values in microseconds.
> + }
> +
> + if(of_property_read_u32(ktz->client->dev.of_node, "led-ramping-time-us", &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);
> + }
Similarly, this code has not adopted the units specified in the
bindings documentation.
In this case 0 would map to 512us so if you decided to use milliseconds
you will need to add comment in the description saying that 0 will map
to 512us because the hardware cannot ramp faster than this!
Daniel.
On Wed, Jan 18, 2023 at 12:08:01PM +0000, Daniel Thompson wrote:
> On Tue, Jan 17, 2023 at 11:44:08PM +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 <[email protected]>
> > ---
> > 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.
> >
> > MAINTAINERS | 6 +
> > drivers/video/backlight/Kconfig | 8 ++
> > drivers/video/backlight/Makefile | 1 +
> > drivers/video/backlight/ktz8866.c | 201 ++++++++++++++++++++++++++++++
> > 4 files changed, 216 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 <[email protected]>
> > S: Maintained
> > F: tools/testing/ktest
> >
> > +KTZ8866 BACKLIGHT DRIVER
> > +M: Jianhua Lu <[email protected]>
> > +S: Maintained
> > +F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> > +F: drivers/video/backlight/ktz8866.c
> > +
> > L3MDEV
> > M: David Ahern <[email protected]>
> > L: [email protected]
> > 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.
>
> s/enabled/enable/ (and sorry for spotting this one so late)
Get it.
>
>
> > +++ b/drivers/video/backlight/ktz8866.c
> > @@ -0,0 +1,201 @@
> > [...]
> > +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-us", &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);
> > + }
>
> This code is interpreting current-ramping-time-us as milliseconds rather
> than microseconds!
>
> I know I used microseconds in the example I proposed in the feedback for
> v4 DT bindings but "something like" means I am merely providing an
> example (mostly I was intending to show that the units should be
> included both in the property name *and* description).
>
> It is up to you whether you fix the mismatch by changing the DT bindings
> document to current-ramping-time-ms or change this code to accept
> values in microseconds.
This is my mistake, sorry.
>
>
> > + }
> > +
> > + if(of_property_read_u32(ktz->client->dev.of_node, "led-ramping-time-us", &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);
> > + }
>
> Similarly, this code has not adopted the units specified in the
> bindings documentation.
>
> In this case 0 would map to 512us so if you decided to use milliseconds
> you will need to add comment in the description saying that 0 will map
> to 512us because the hardware cannot ramp faster than this!
Get it, thank you very much.
>
>
> Daniel.