Re: [PATCH 6/6] OMAPDSS: HDMI: Create platform device to support audio

[Ricardo Neri <ricardo.neri@ti.com>]

On 10/23/2012 11:29 PM, Tomi Valkeinen wrote:
> On 2012-10-23 20:21, Ricardo Neri wrote:
>
>>> If so, you could pass only that one address, instead of the whole HDMI
>>> register space?
>> Yes, that could work. I thought about that but the common HDMI driver
>> would have to know the the IP-specific register, which it should not.
>
> Argh, of course...
>
>> Perhaps the IP-specific register address can be passed by a IP-specific
>> function such as hdmi_get_audio_dma_port for the common HDMI driver to
>> populate the resource.
>>
>> Btw, could this be another reason to convert the IP-specific libraries
>> to drivers?
>
> Yes, I think it makes more and more sense to do that.
>
>> Even though this would allow our HDMI drivers to be more inline with
>> what other HDMI drivers do, things like power management and interrupts
>> are still handled by DSS, unlike x86, for instance [1][2]. So the audio
>> drivers will still depend on DSS. Also, the register layout is different
>> for OMAP5 and audio registers are even more scattered. Furthermore, the
>> common HDMI driver would have to know the IP-specific layout to know
>> what register spaces expose to the audio driver (another reason to have
>> IP-specific drivers?). So I would vote for continuing using the omapdss
>> audio interface.
>
> Okay.
>
> I think your approach is ok for the time being. I don't like passing the
> whole register space to the audio driver, but that's the best we can do
> with the current driver.

What about for now having a function in the IP library to be called from 
the common driver to determine the address of the port? Something like[1]:

	res = platform_get_resource_byname(hdmi.pdev,
					   IORESOURCE_MEM, "hdmi_wp");

	aud_offset = hdmi.ip_data.ops->audio_get_dma_port_off();
	aud_res[0].start = res->start + aud_offset;
	aud_res[0].end = res->start + aud_offset + 3;


>
> Have you looked at converting to IP specific drivers? Any idea of the
> effort? I'd like it to be done with the omap4 hdmi driver first, before
> merging omap5 hdmi into the mainline, if at all possible.
>
As a first step, I have started implementing a separate driver for the 
TPD12S015 as you suggested in the past. For converting the IP libraries 
into drivers, I still don't see how to keep them independent of omapdss 
to be reusable by DaVinci platforms (but afaik they are not using our 
libraries anyways). Maybe, a thin compatibility layer for omapdss (the 
hdmi_panel)? I still don't  have a clear idea. :/

BR,

Ricardo

[1]. 
http://gitorious.org/omap-audio/linux-audio/blobs/ricardon/topic/3.7-hdmi-clean/drivers/video/omap2/dss/hdmi.c#line1098

>   Tomi
>
>