[PATCH 03/10] arm64: dts: imx8mp-skov: use I2C5 for DDC

[Frank Li]

On Thu, Dec 19, 2024 at 06:43:56PM +0100, Ahmad Fatoum wrote:
> Hello Frank,
>
> On 19.12.24 18:34, Frank Li wrote:
> > On Thu, Dec 19, 2024 at 08:25:27AM +0100, Ahmad Fatoum wrote:
> >> The HDMI DDC pads can be muxed either to an i.MX I2C controller or
> >> to a limited I2C controller within the Designware HDMI bridge.
> >>
> >> So far we muxed the pads to the HDMI bridge, but the i.MX I2C controller
> >> is the better choice:
> >
> > Switch to the i.MX I2C controller because
> >
> >>
> >>   - We use DDC/CI commands for display brightness configuration, but the
> >>     Linux driver refuses[1] transfers to/from address 0x37, because the
> >>     controller doesn't support multi-byte requests.
> >
> >       Designware HDMI Limited I2C controller doesn't support multi-byte
> > requests and display brightness configuration by DDC/CI command need it.
> >
> >>
> >>   - The driver doesn't support I2C bus recovery, but we need that,
> >>     because some HDMI panels used with the board can be flaky.
> >
> >       Designware HDMI Limited I2C controller doesn't support I2C bus
> > recovery.
> >
> >>
> >> As the i.MX I2C controller doesn't have either of these limitations,
> >> let's make use of it instead.
> >
> > Reduntant. can be removed.
>
> Sorry, I am very much open to review feedback, but I fail to see how
> your subjective take improves things.

Ref https://docs.kernel.org/process/submitting-patches.html

"Describe your changes in imperative mood, e.g. “make xyzzy do frotz”
instead of “[This patch] makes xyzzy do frotz” or “[I] changed xyzzy to do
frotz”, as if you are giving orders to the codebase to change its behaviour."

Avoid use "we(same as "I" in above example) ..."

Frank

>
> Thanks,
> Ahmad
>
>
>
>
> >
> > Frank
> >>
> >> [1]: https://lore.kernel.org/all/20190722181945.244395-1-mka@chromium.org/
> >>
> >> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> >> ---
> >>  .../boot/dts/freescale/imx8mp-skov-revb-hdmi.dts   | 26 ++++++++++++++++++++--
> >>  1 file changed, 24 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts b/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts
> >> index c1ca69da3cb8..206116be8166 100644
> >> --- a/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts
> >> +++ b/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts
> >> @@ -9,12 +9,34 @@ / {
> >>  	compatible = "skov,imx8mp-skov-revb-hdmi", "fsl,imx8mp";
> >>  };
> >>
> >> +&i2c5 {
> >> +	pinctrl-names = "default", "gpio";
> >> +	pinctrl-0 = <&pinctrl_i2c5>;
> >> +	pinctrl-1 = <&pinctrl_i2c5_gpio>;
> >> +	scl-gpios = <&gpio3 26 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
> >> +	sda-gpios = <&gpio3 27 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
> >> +	clock-frequency = <100000>;
> >> +	status = "okay";
> >> +};
> >> +
> >>  &iomuxc {
> >>  	pinctrl_hdmi: hdmigrp {
> >>  		fsl,pins = <
> >> -			MX8MP_IOMUXC_HDMI_DDC_SCL__HDMIMIX_HDMI_SCL		0x1c3
> >> -			MX8MP_IOMUXC_HDMI_DDC_SDA__HDMIMIX_HDMI_SDA		0x1c3
> >>  			MX8MP_IOMUXC_HDMI_HPD__HDMIMIX_HDMI_HPD			0x19
> >>  		>;
> >>  	};
> >> +
> >> +	pinctrl_i2c5: i2c5grp {
> >> +		fsl,pins = <
> >> +			MX8MP_IOMUXC_HDMI_DDC_SCL__I2C5_SCL			0x400001c2
> >> +			MX8MP_IOMUXC_HDMI_DDC_SDA__I2C5_SDA			0x400001c2
> >> +		>;
> >> +	};
> >> +
> >> +	pinctrl_i2c5_gpio: i2c5gpiogrp {
> >> +		fsl,pins = <
> >> +			MX8MP_IOMUXC_HDMI_DDC_SCL__GPIO3_IO26			0x400001c2
> >> +			MX8MP_IOMUXC_HDMI_DDC_SDA__GPIO3_IO27			0x400001c2
> >> +		>;
> >> +	};
> >>  };
> >>
> >> --
> >> 2.39.5
> >>
> >
>
>
> --
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