Re: [alsa-devel] [PATCH 1/2] ASoC: rockchip: i2s: add 8 channels capture and lrck-mode support

From: Caleb Crome <caleb@crome.org>
To: sugar <sugar.zhang@rock-chips.com>
Cc: Mark Brown <broonie@kernel.org>,
	alsa-devel@alsa-project.org, heiko@sntech.de,
	linux-kernel@vger.kernel.org, lgirdwood@gmail.com,
	tiwai@suse.com, linux-rockchip@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [alsa-devel] [PATCH 1/2] ASoC: rockchip: i2s: add 8 channels capture and lrck-mode support
Date: Wed, 7 Oct 2015 06:04:51 -0700	[thread overview]
Message-ID: <F2F204F7-F5A8-4152-BF1D-454EB3E35F34@crome.org> (raw)
In-Reply-To: <5614D162.3020500@rock-chips.com>

Hi sugar,
   Can the rockchip support more than 8 channels?  Ideally, we would like to capture 16 channels and playback 16 channels simultaneously.  

Thanks,  Caleb 

Sent from my iPhone

> On Oct 7, 2015, at 1:01 AM, sugar <sugar.zhang@rock-chips.com> wrote:
> 
> Sorry for late reply, we were in the National Day Holiday.
> 
>> 在 10/1/2015 02:46, Mark Brown 写道:
>>> On Mon, Sep 28, 2015 at 04:16:12PM +0800, sugar wrote:
>>> 在 9/24/2015 00:24, Mark Brown 写道:
>> 
>>>> My initial thought here is that the machine driver should be responsible
>>>> for setting this and then the DAI driver should check to see if
>>>> symmetric_rates are in use and configure itself appropriately.  Is there
>>>> a reason why this won't work here?
>> 
>>> It's for i2s ip configuration, in the most situation, there is no need
>>> to use this property, except one case:
>> 
>>> In order to save gpio pins for other function use, we may use single
>>> lrck(tx or rx) pin. of course, it depends on product design. when in i2s
>>> slave mode, we need to configure this to share lrck with tx/rx inside i2s
>>> logic.
>> 
>>> symmetric_rates flag works fine on rockchip platform, but it can't cover the
>>> above case.
>> 
>>> Do you have any suggestion about this or maybe there is no need to upstream
>>> this special part?
>> 
>> What makes you say that the symmetric_rates flag can't be used to cover
>> this case?  What you describe above is hte normal reason for needing to
>> enforce symmetric_rates.  The driver should be able to check if the flag
>> has been set just as well as the core is.
> 
> Got it, How about the following modify?
> 
> if (dai->symmetric_rates)
>    regmap_update_bits(i2s->regmap, I2S_CKR,
>                           I2S_CKR_TRCM_MASK,
>                           I2S_CKR_TRCM(val));
> 
> 
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