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 <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. > 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 <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. 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.
