Hi Geert,
Le jeu., nov. 25 2021 at 08:58:13 +0100, Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx> a écrit :
Hi Nikolaus,
On Wed, Nov 24, 2021 at 5:31 PM H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> wrote:
> Am 24.11.2021 um 17:21 schrieb Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx>:
> On Wed, Nov 24, 2021 at 5:19 PM H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> wrote:
>>> Am 23.11.2021 um 21:10 schrieb Paul Cercueil
<paul@xxxxxxxxxxxxxxx>:
>>> Le mar., nov. 23 2021 at 19:13:59 +0100, H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> 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).
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
