[PATCH v9 1/2] dt-bindings: leds: backlight: Add Kinetic KTZ8866 backlight

[PATCH v9 1/2] dt-bindings: leds: backlight: Add Kinetic KTZ8866 backlight

[Jianhua Lu]

Add Kinetic KTZ8866 backlight binding documentation.

Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
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.

Changes in v6:
  - Correct wrong property suffix and description.

Changes in v7:
  - Add vddpos and vddeg supply.
  - Use enable-gpios instead of defining enable pin.

Changes in v8:
  - Rename current ramping time. 
  - Rename led ramping time. 

Changes in v9:
  - Add Krzysztof's R-b.
  - Add missing 1μs to the enum of "kinetic,led-enable-ramp-delay-ms".

 .../leds/backlight/kinetic,ktz8866.yaml       | 76 +++++++++++++++++++
 1 file changed, 76 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..e1191453c2f0
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
@@ -0,0 +1,76 @@
+# 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-channels-current-sinks
+  led backlight with dual lcd bias power.
+  https://www.kinet-ic.com/ktz8866/
+
+allOf:
+  - $ref: common.yaml#
+
+properties:
+  compatible:
+    const: kinetic,ktz8866
+
+  vddpos-supply:
+    description: positive boost supply regulator.
+
+  vddneg-supply:
+    description: negative boost supply regulator.
+
+  enable-gpios:
+    description: GPIO to use to enable/disable the backlight (HWEN pin).
+    maxItems: 1
+
+  current-num-sinks:
+    description: number of the LED current sinks' channels.
+    enum: [1, 2, 3, 4, 5, 6]
+
+  kinetic,current-ramp-delay-ms:
+    description: |
+      LED current ramping delay time in milliseconds, note that the
+      case 1 will be mapped to 1μs.
+    enum: [1, 2, 4, 8, 16, 32, 64, 128, 192, 256, 320, 384, 448, 512, 576, 640]
+
+  kinetic,led-enable-ramp-delay-ms:
+    description: |
+      LED on/off ramping delay time in milliseconds, note that the case 0 will be
+      mapped to 512μs because ktz8866 can't ramp faster than it.
+    enum: [0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384]
+
+  kinetic,enable-lcd-bias:
+    description: Set if we want to output bias power supply for LCD.
+    type: boolean
+
+required:
+  - compatible
+  - vddpos-supply
+  - vddneg-supply
+  - enable-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    backlight {
+        compatible = "kinetic,ktz8866";
+
+        vddpos-supply = <&bl_vddpos_5p5>;
+        vddneg-supply = <&bl_vddneg_5p5>;
+        enable-gpios = <&tlmm 139 GPIO_ACTIVE_HIGH>;
+        current-num-sinks = <5>;
+        kinetic,current-ramp-delay-ms = <128>;
+        kinetic,led-enable-ramp-delay-ms = <1>;
+        kinetic,enable-lcd-bias;
+    };
-- 
2.39.1

[PATCH v9 2/2] backlight: ktz8866: Add support for Kinetic KTZ8866 backlight

[Jianhua Lu]

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.

Changes in v5:
  - Change "2023" to "2022, 2023" in Copyright line.
  - Set scale property for backlight.

Changes in v6:
  - Correct devicetree property name.

Changes in v7:
  - Remove unnecessary sleep statement.
  - Fix code style.
  - Add vddpos and vddneg supply devicetree parse.
  - Add enabel-gpio devicetree parse.

Changes in v8:
  - Modify devicetree parse according to dt bindings.

No changes in v9

 MAINTAINERS                       |   6 +
 drivers/video/backlight/Kconfig   |   8 ++
 drivers/video/backlight/Makefile  |   1 +
 drivers/video/backlight/ktz8866.c | 209 ++++++++++++++++++++++++++++++
 4 files changed, 224 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..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..97b723719e13
--- /dev/null
+++ b/drivers/video/backlight/ktz8866.c
@@ -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");
-- 
2.39.1

Re: [PATCH v9 1/2] dt-bindings: leds: backlight: Add Kinetic KTZ8866 backlight

[Daniel Thompson]

On Fri, Jan 20, 2023 at 11:50:17PM +0800, Jianhua Lu wrote:
> Add Kinetic KTZ8866 backlight binding documentation.
>
> Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


Daniel.

Re: [PATCH v9 2/2] backlight: ktz8866: Add support for Kinetic KTZ8866 backlight

[Daniel Thompson]

On Fri, Jan 20, 2023 at 11:50:18PM +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>

Thanks for all the changes!

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


Daniel.

Re: [PATCH v9 1/2] dt-bindings: leds: backlight: Add Kinetic KTZ8866 backlight

[Lee Jones]

On Fri, 20 Jan 2023, Jianhua Lu wrote:

> Add Kinetic KTZ8866 backlight binding documentation.
> 
> Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
> 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.
> 
> Changes in v6:
>   - Correct wrong property suffix and description.
> 
> Changes in v7:
>   - Add vddpos and vddeg supply.
>   - Use enable-gpios instead of defining enable pin.
> 
> Changes in v8:
>   - Rename current ramping time. 
>   - Rename led ramping time. 
> 
> Changes in v9:
>   - Add Krzysztof's R-b.
>   - Add missing 1μs to the enum of "kinetic,led-enable-ramp-delay-ms".
> 
>  .../leds/backlight/kinetic,ktz8866.yaml       | 76 +++++++++++++++++++
>  1 file changed, 76 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml

Applied, thanks

-- 
Lee Jones [李琼斯]

Re: [PATCH v9 2/2] backlight: ktz8866: Add support for Kinetic KTZ8866 backlight

[Lee Jones]

On Fri, 20 Jan 2023, 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.
> 
> Changes in v5:
>   - Change "2023" to "2022, 2023" in Copyright line.
>   - Set scale property for backlight.
> 
> Changes in v6:
>   - Correct devicetree property name.
> 
> Changes in v7:
>   - Remove unnecessary sleep statement.
>   - Fix code style.
>   - Add vddpos and vddneg supply devicetree parse.
>   - Add enabel-gpio devicetree parse.
> 
> Changes in v8:
>   - Modify devicetree parse according to dt bindings.
> 
> No changes in v9
> 
>  MAINTAINERS                       |   6 +
>  drivers/video/backlight/Kconfig   |   8 ++
>  drivers/video/backlight/Makefile  |   1 +
>  drivers/video/backlight/ktz8866.c | 209 ++++++++++++++++++++++++++++++
>  4 files changed, 224 insertions(+)
>  create mode 100644 drivers/video/backlight/ktz8866.c

Applied, thanks

-- 
Lee Jones [李琼斯]