linux-kernel - Re: [PATCH v5 1/2] usb: typec: altmodes/displayport: add support for embedded DP cases

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Date:   Tue, 22 Aug 2023 16:39:43 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 1/2] usb: typec: altmodes/displayport: add support for
 embedded DP cases

On Thu, Aug 17, 2023 at 06:08:23PM +0300, Dmitry Baryshkov wrote:
> In the embedded cases, the DisplayPort connector is handled by the TCPM
> itself. It was proposed to add the "displayport" OF property to the DT
> bindings, but it  was rejected in favour of properly describing the
> electrical signal path using of_graph.
> 
> Fallback to the controller fwnode for HPD notifications to
> support such usecases without requiring additional DT properties.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
>  drivers/usb/typec/altmodes/displayport.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index bc4af130940d..a4cf1045b535 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -594,7 +594,10 @@ int dp_altmode_probe(struct typec_altmode *alt)
>  	alt->ops = &dp_altmode_ops;
>  
>  	fwnode = dev_fwnode(alt->dev.parent->parent); /* typec_port fwnode */
> -	dp->connector_fwnode = fwnode_find_reference(fwnode, "displayport", 0);
> +	if (fwnode_property_present(fwnode, "displayport"))
> +		dp->connector_fwnode = fwnode_find_reference(fwnode, "displayport", 0);
> +	else
> +		dp->connector_fwnode = fwnode_handle_get(fwnode); /* embedded DP */
>  	if (IS_ERR(dp->connector_fwnode))
>  		dp->connector_fwnode = NULL;
>  
> -- 
> 2.39.2

-- 
heikki