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

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:

quoted

On Tue, Jan 17, 2023 at 09:47:41PM +0800, Jianhua Lu wrote:

quoted

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 [off-list ref]

quoted

+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 )


Daniel.