linux-kernel - Re: [PATCH] ASoC: tlv320aic31xx: Remove regulator notification handling

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Message-ID: <20180904154905.GH12993@sirena.org.uk>
Date:   Tue, 4 Sep 2018 16:49:05 +0100
From:   Mark Brown <broonie@...nel.org>
To:     "Andrew F. Davis" <afd@...com>
Cc:     Liam Girdwood <lgirdwood@...il.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ASoC: tlv320aic31xx: Remove regulator notification
 handling

On Tue, Sep 04, 2018 at 10:03:40AM -0500, Andrew F. Davis wrote:
> On 09/04/2018 09:57 AM, Mark Brown wrote:

> > It's there to save us having to rewrite the register cache if we asked
> > for the device to be powered down but that didn't actually happen due to
> > other constraints, we know all the registers are still as we left them.

> I don't see that happening for any other user of this, we will still
> have to re-write the cache when the device goes from OFF->STANDBY, and

You will?  All the power_off() code seems to do is mark the regmap as
cache only and turn off the regulators.

> if it stays in standby and never went off, then we are still broken as
> we switched to using the register cache only, but never turned on real
> writes again.

regmap can remember which registers were written to while in cache only
mode and only sync the ones that are actually dirty, or you can
invalidate the entire cache.

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