Hi Geert,

Le jeu., nov. 25 2021 at 08:58:13 +0100, Geert Uytterhoeven 
[off-list ref] a écrit :

Hi Nikolaus,

On Wed, Nov 24, 2021 at 5:31 PM H. Nikolaus Schaller 
[off-list ref] wrote:

quoted

 > Am 24.11.2021 um 17:21 schrieb Geert Uytterhoeven 
[off-list ref]:
 > On Wed, Nov 24, 2021 at 5:19 PM H. Nikolaus Schaller 
[off-list ref] wrote:
 >>> Am 23.11.2021 um 21:10 schrieb Paul Cercueil 
[off-list ref]:
 >>> Le mar., nov. 23 2021 at 19:13:59 +0100, H. Nikolaus Schaller 
[off-list ref] a écrit :
 >>>> +    assigned-clock-rates = <48000000>, <0>, <54000000>, <0>, 
<27000000>;
 >>>> };
 >>>> &tcu {
 >>>> @@ -509,6 +534,19 @@ pins_i2c4: i2c4 {
 >>>>             bias-disable;
 >>>>     };
 >>>> +    pins_hdmi_ddc: hdmi_ddc {
 >>>> +            function = "hdmi-ddc";
 >>>> +            groups = "hdmi-ddc";
 >>>> +            bias-disable;
 >>>> +    };
 >>>> +
 >>>> +    /* switch to PF25 as gpio driving DDC_SDA low */
 >>>> +    pins_hdmi_ddc_unwedge: hdmi_ddc {
 >>>> +            function = "hdmi-ddc";
 >>>> +            groups = "hdmi-ddc";
 >>>> +            bias-disable;
 >>>> +    };
 >>>
 >>> Your pins_hdmi_ddc and pins_hdmi_ddc_unwedge are the exact 
same? You could just use the former and pass it to both pinctrl-0 
and pinctrl-1.
 >>
 >> This was forgotten to remove. We do not make use of the unwedge 
feature because I could not find out how to use pinctrl to switch 
this to gpio25 and drive it low.
 >
 > Using gpio-hog?

 well, AFAIR it activates the gpio permanently and is a propery of 
the gpio controller and not of pinmux.

Yes, hogs are permanently (ignoring DT overlay tricks).

quoted

 The driver assumes it can use pinmux state switching to drive the 
DDC_SDA line low on demand.

Add an optional wedge-gpios property for switching?

I think you can use a pinctrl state as well, specifying the pin and the 
'output-low' property.

-Paul