Hi Paul,
> Am 02.02.2022 um 11:32 schrieb Paul Cercueil <p...@crapouillou.net>:
>
> Hi Nikolaus,
>
> Le lun., janv. 31 2022 at 13:26:53 +0100, H. Nikolaus Schaller
> <h...@goldelico.com> a écrit :
>> "hdmi-connector.yaml" bindings defines an optional property
>> "ddc-en-gpios" for a single gpio to enable DDC operation.
>> Usually this controls +5V power on the HDMI connector.
>> This +5V may also be needed for HPD.
>> This was not reflected in code.
>> Now, the driver activates the ddc gpio after probe and
>> deactivates after remove so it is "almost on".
>> But only if this driver is loaded (and not e.g. blacklisted
>> as module).
>> Signed-off-by: H. Nikolaus Schaller <h...@goldelico.com>
>> ---
>> drivers/gpu/drm/bridge/display-connector.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>> diff --git a/drivers/gpu/drm/bridge/display-connector.c
>> b/drivers/gpu/drm/bridge/display-connector.c
>> index d24f5b90feabf..555395e301096 100644
>> --- a/drivers/gpu/drm/bridge/display-connector.c
>> +++ b/drivers/gpu/drm/bridge/display-connector.c
>> @@ -24,6 +24,7 @@ struct display_connector {
>> int hpd_irq;
>> struct regulator *dp_pwr;
>> + struct gpio_desc *ddc_en;
>> };
>> static inline struct display_connector *
>> @@ -345,6 +346,19 @@ static int display_connector_probe(struct
>> platform_device *pdev)
>> }
>> }
>> + /* enable DDC */
>> + if (type == DRM_MODE_CONNECTOR_HDMIA) {
>> + conn->ddc_en = devm_gpiod_get_optional(&pdev->dev, "ddc-en",
>> + GPIOD_OUT_HIGH);
>> +
>> + if (IS_ERR(conn->ddc_en)) {
>> + dev_err(&pdev->dev, "Couldn't get ddc-en gpio\n");
>> + return PTR_ERR(conn->ddc_en);
>> + }
>> +
>> + gpiod_set_value(conn->ddc_en, 1);
>
> You already requested the gpio with the GPIOD_OUT_HIGH flag, so this can be
> removed.
Ah, ok!
>
>
>> + }
>> +
>> conn->bridge.funcs = &display_connector_bridge_funcs;
>> conn->bridge.of_node = pdev->dev.of_node;
>> @@ -373,6 +387,9 @@ static int display_connector_remove(struct
>> platform_device *pdev)
>> {
>> struct display_connector *conn = platform_get_drvdata(pdev);
>> + if (conn->ddc_en)
>> + gpiod_set_value(conn->ddc_en, 0);
>
> Note that gpiod_set_value() already does the null-check internally.
Indeed.
> I actually do prefer your solution, so this is fine with me, but maintainers
> may have a different opinion.
I am fine with any of them. Just need to know which one to take (and test).
BR,
Nikolaus
>
> Cheers,
> -Paul
>
>> +
>> if (conn->dp_pwr)
>> regulator_disable(conn->dp_pwr);
>> --
>> 2.33.0
>
>
