Re: [PATCH v5 1/2] ARM: dts: imx6: Add support for Toradex Apalis iMX6Q/D SoM

Stefan Agner
2016-08-29T21:00:06Z

On 2016-08-29 06:28, Vladimir Zapolskiy wrote:
> Hi Marcel,
>
> On 02/05/2016 06:12 PM, Marcel Ziswiler wrote:
>> From: Petr Štetiar <ynezz@true.cz>
>>
>> Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
>> Signed-off-by: Petr Štetiar <ynezz@true.cz>
>> Reviewed-by: Stefan Agner <stefan@agner.ch>
>> ---
>>
>
> because the change is in mainline now below is kind of out of date
> information, but you may find it helpful.
>
> [snip]
>
>> - fixed HDMI DDC (requires GPIO-based bitbanging I2C to be enabled)
>
> This is not needed.
>
> [snip]
>
>> + /* DDC_I2C: I2C2_SDA/SCL on MXM3 205/207 */
>> + i2cddc: i2c@0 {
>> + compatible = "i2c-gpio";
>> + pinctrl-names = "default";
>> + pinctrl-0 = <&pinctrl_i2c_ddc>;
>> + gpios = <&gpio3 16 GPIO_ACTIVE_HIGH /* sda */
>> + &gpio2 30 GPIO_ACTIVE_HIGH /* scl */
>> + >;
>> + i2c-gpio,delay-us = <2>; /* ~100 kHz */
>> + status = "disabled";
>> + };
>> +
>
> This is not needed.
>
> [snip]
>
>> + pinctrl_i2c_ddc: gpioi2cddcgrp {
>> + fsl,pins = <
>> + /* DDC bitbang */
>> + MX6QDL_PAD_EIM_EB2__GPIO2_IO30 0x1b0b0
>> + MX6QDL_PAD_EIM_D16__GPIO3_IO16 0x1b0b0
>> + >;
>> + };
>> +
>
> Practically you don't need this overcomplicated GPIO-based bitbanging
> to emulate I2C, because the DW HDMI controller has a reduced I2C
> controller on board, you may take a look at its support published here:
>
> http://www.spinics.net/lists/dri-devel/msg116308.html
>
> To utilize it the pads should be set to HDMI function instead of
> I2C or GPIO.

Thanks for the notification! I guess we'd also have to remove...

+&hdmi {
+ ddc-i2c-bus = <&i2cddc>;

...this line...

+ status = "okay";
+};
+
+&i2cddc {
+ status = "okay";
+};

and this from arch/arm/boot/dts/imx6q-apalis-ixora.dts.

--
Stefan