linux-kernel - Re: [alsa-devel] [PATCH] ASoC: cs42l56: Fix misuse of regmap_update

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Message-ID: <20161201094200.GK1867@localhost.localdomain>
Date:   Thu, 1 Dec 2016 09:42:00 +0000
From:   Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
To:     Florian Vaussard <florian.vaussard@...il.com>
CC:     Brian Austin <brian.austin@...rus.com>,
        Paul Handrigan <Paul.Handrigan@...rus.com>,
        <alsa-devel@...a-project.org>, Liam Girdwood <lgirdwood@...il.com>,
        <linux-kernel@...r.kernel.org>,
        Florian Vaussard <florian.vaussard@...g-vd.ch>,
        Takashi Iwai <tiwai@...e.com>, Mark Brown <broonie@...nel.org>
Subject: Re: [alsa-devel] [PATCH] ASoC: cs42l56: Fix misuse of
 regmap_update_bits

On Tue, Nov 29, 2016 at 06:10:49PM +0100, Florian Vaussard wrote:
> Using regmap_update_bits(..., mask, 1) with 'mask' following (1 << k)
> and k greater than 0 is wrong. Indeed, _regmap_update_bits will perform
> (mask & 1), which results in 0 if LSB of mask is 0. Thus the call
> regmap_update_bits(..., mask, 1) is in reality equivalent to
> regmap_update_bits(..., mask, 0).
> 
> In such a case, the correct use is regmap_update_bits(..., mask, mask).
> 
> This driver is performing such a mistake with the CS42L56_AIN*_REF_MASK
> masks, which equal 0x10, 0x20, 0x40 and 0x80. Fix the driver to make it
> consistent with the API. Please note that this change is untested,
> as I do not have this piece of hardware. Testers are welcome!
> 
> Signed-off-by: Florian Vaussard <florian.vaussard@...g-vd.ch>
> ---

Looks good to me:

Reviewed-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>

Thanks,
Charles