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

From: Daniel Thompson
Date: Tue Jan 17 2023 - 09:37:18 EST


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@xxxxxxxxx>
> > > ---
> > > 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@xxxxxxxxxxxxxx>
> > > S: Maintained
> > > F: tools/testing/ktest
> > >
> > > +KTZ8866 BACKLIGHT DRIVER
> > > +M: Jianhua Lu <lujianhua000@xxxxxxxxx>
> > > +S: Maintained
> > > +F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> > > +F: drivers/video/backlight/ktz8866.c
> > > +
> > > L3MDEV
> > > M: David Ahern <dsahern@xxxxxxxxxx>
> > > L: netdev@xxxxxxxxxxxxxxx
> > > 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@xxxxxxxxx>
> >
> > Shouldn't this be:
> > Copyright (C) 2022, 2023 Jianhua Lu <lujianhua000@xxxxxxxxx>
> >
> > > +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.