Re: [PATCH 1/2] drm/bridge: ti-tfp410: support hpd via gpio

From: Archit Taneja <architt@codeaurora.org>
To: Jyri Sarha <jsarha@ti.com>,
	Christopher Spinrath <christopher.spinrath@rwth-aachen.de>
Cc: Mark Rutland <mark.rutland@arm.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Shawn Guo <shawnguo@kernel.org>,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	DRI mailing list <dri-devel@lists.freedesktop.org>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	Igor Grinberg <grinberg@compulab.co.il>,
	Sascha Hauer <kernel@pengutronix.de>,
	Fabio Estevam <fabio.estevam@nxp.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/2] drm/bridge: ti-tfp410: support hpd via gpio
Date: Thu, 30 Mar 2017 15:19:05 +0530	[thread overview]
Message-ID: <ecd1c4b5-c1c7-ece2-4139-a4d6cfb48da3@codeaurora.org> (raw)
In-Reply-To: <f87195b3-bd89-d698-c935-4e3aa97c01e2@ti.com>

On 03/28/2017 07:02 PM, Jyri Sarha wrote:
> On 03/27/17 08:58, Archit Taneja wrote:
>> Hi,
>>
>> On 03/07/2017 03:21 AM, Christopher Spinrath wrote:
>>> Hi Fabio,
>>>
>>> On 03/06/2017 10:46 PM, Fabio Estevam wrote:
>>>> Hi Christopher,
>>>>
>>>> On Mon, Mar 6, 2017 at 6:40 PM,
>>>> <christopher.spinrath@rwth-aachen.de> wrote:
>>>>> From: Christopher Spinrath <christopher.spinrath@rwth-aachen.de>
>>>>>
>>>>> On some boards the hpd pin of a hdmi connector is wired up to a gpio
>>>>> pin. Since in the DRM world the tfp410 driver is responsible for
>>>>> handling the connector, add support for hpd gpios in this very driver.
>>>>>
>>>>> Signed-off-by: Christopher Spinrath
>>>>> <christopher.spinrath@rwth-aachen.de>
>>>>> ---
>>>>>  drivers/gpu/drm/bridge/ti-tfp410.c | 72
>>>>> ++++++++++++++++++++++++++++++++++++--
>>>>
> ...
>>>
>>
>> The patch looks good to me.
>>
>> Jyri,
>>
>> Is it possible for you to verify this on Beaglebone platform?
>>
>
> If I read my BeagleBone DVI-D Cape docs right, it does not have the HPD
> pin connected. At least it does not mention any gpio that could be used
> for the purpose. So I can not easily test this patch in real world
> situation. For what it is worth the patch looks ok to me too.

Thanks for the review. I looked at the tfp410 data sheet[1], there isn't
a HPD pin on the chip at all. My guess is that boards using tfp410 most
likely have the HPD pin routed to the SoC from the HDMI connector
(with a level shifter/shield in between).

We would eventually need to move the both ddc and hpd stuff to
a generic hdmi connector driver later on. I've queued this to
drm-misc-next.

[1]: http://www.ti.com/lit/ds/symlink/tfp410.pdf

Archit

>
> Best regards,
> Jyri
>
>
> _______________________________________________
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> linux-arm-kernel@lists.infradead.org
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>

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