Re: [ADV7393] DRM Encoder Slave or DRM Bridge

From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: Vikas Patil <vikasmpatil@gmail.com>
Cc: "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
Subject: Re: [ADV7393] DRM Encoder Slave or DRM Bridge
Date: Thu, 15 Sep 2016 12:53:57 +0300	[thread overview]
Message-ID: <406769ce-bbd0-c517-3006-c5f1ab6ff511@ti.com> (raw)
In-Reply-To: <CA+kt3u0pvW8Zn171wVCWTswYbk9dOtd0SpOJg5ytBy5nMy1irg@mail.gmail.com>

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On 15/09/16 12:44, Vikas Patil wrote:
> On Wed, Sep 14, 2016 at 3:04 PM, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
>>
>>
>> On 13/09/16 16:13, Vikas Patil wrote:
>>> Thanks Tomi for quick comment.
>>>
>>> I am thinking to base adv7393 driver on
>>> "drivers\gpu\drm\omapdrm\displays\encoder-tc358768.c" as I don't think
>>> any similar to adv7393 chip driver available. Could you please comment
>>> if this will help to get adv chip running?
>>
>> I presume you're not using mainline kernel, as that driver is not there.
>> I'm not familiar with adv7393, but yes, I think you can use that as an
>> example.
>>
> 
> Thanks a lot for your comments. I am using latest (i.e. 3.00.00.03 )
> Processor SDK Linux Automotive which is based on linux 4.4.14.
> 
> As my display panel is connected as follows. I am little confused over
> the values I need to set for following properties in probe function.
> 
> DPI1/VOUT1 -----16bit DRGB---> ADV7393 (Digital to Analog video
> encoder) ------> CVBS Out ------> Display Panel
> 
> 
>      dssdev->ops.dpi = &adv7393_dpi_ops; (atv?)
>     dssdev->type = OMAP_DISPLAY_TYPE_DPI;
>     dssdev->output_type = OMAP_DISPLAY_TYPE_DPI; (Do I need to use
> OMAP_DISPLAY_TYPE_VENC, but DRA74x do not have VENC Encoder I think)
>     dssdev->phy.dpi.data_lines = ddata->dpi_ndl;
>     dssdev->port_num = 1;
> 
> 
> As adv7393 takes 16-bit DRGB as input and gives composite as output,
> does above configuration looks correct? or Do I need to change to
> something else (e.g. dpi,sdi,dvi, hdmi, atv, dsi)?

The API is quite messy (full of legacy)...

But the "ops" there are for the "downstream" direction, i.e. towards the
connector. So here you should have atv ops. You should then have
connector-analog-tv as a device after adv7393, and that connector driver
will be calling those atv ops.

adv7393 itself will be calling dpi ops, offered by the DSS.

You should set dssdev->type to DPI (that's the input).
dssdev->output_type to OMAP_DISPLAY_TYPE_VENC (output, although "venc"
is not quite correct here, but closest match we have). DRA74x doesn't
have VENC, but this is what the adv7393 outputs.

 Tomi

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