linux-kernel - Re: [PATCH v2] ASoC: fsl_esai: Add ESAI CPU DAI driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20140110164543.GB17609@MrMyself>
Date:	Sat, 11 Jan 2014 00:45:44 +0800
From:	Nicolin Chen <Guangyu.Chen@...escale.com>
To:	Mark Brown <broonie@...nel.org>
CC:	<timur@...i.org>, <alsa-devel@...a-project.org>,
	<robh+dt@...nel.org>, <pawel.moll@....com>, <mark.rutland@....com>,
	<ijc+devicetree@...lion.org.uk>, <galak@...eaurora.org>,
	<rob@...dley.net>, <lgirdwood@...il.com>, <perex@...ex.cz>,
	<tiwai@...e.de>, <grant.likely@...aro.org>, <shawn.guo@...aro.org>,
	<devicetree@...r.kernel.org>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH v2] ASoC: fsl_esai: Add ESAI CPU DAI driver

On Fri, Jan 10, 2014 at 04:52:29PM +0000, Mark Brown wrote:
> On Fri, Jan 10, 2014 at 11:48:25PM +0800, Nicolin Chen wrote:
> 
> > I think I start to understand the point here: If a user only needs to playback
> > the default case - 44.1KHz for example, the driver can just configure all the
> > dividers once at the beginning, not every time, so that we can save further
> > register overriding operation or even complicated clock selection and divisor
> > calculation, which obviously makes the procedure clean and reduces the system
> > loading even if it might be just in a slight level.
> 
> > Is this the reason, or maybe one of the reasons, to the defaults providing?
> 
> The main thing is that if the DAI driver does it then it's less code in
> the machine drivers using it - what tends to happen otherwise is that
> quite a few machine drivers end up replicating the same logic.  Hardware
> designers tend to do a lot of cut'n'paste with these things so even if
> the CODEC is different the clocking is often very similar.

Point taken. And it also depends on how common the defaults would be.
I think I should try to figure out a comparably generic template for
the clock selection and its rate settings here and also check other
redundant places.

I learned another lesson today. Thank you indeed.
Nicolin

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/