linux-kernel - Re: [RFC 4/7] mfd: ocelot-spi: Change the regmap stride to reflect the real one

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Message-ID: <826e295b-6a0b-4015-85bc-5ba6015678dc@lunn.ch>
Date:   Mon, 27 Mar 2023 02:02:55 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Maxime Chevallier <maxime.chevallier@...tlin.com>
Cc:     Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        rafael@...nel.org, Colin Foster <colin.foster@...advantage.com>,
        Vladimir Oltean <vladimir.oltean@....com>,
        Lee Jones <lee@...nel.org>, davem@...emloft.net,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        thomas.petazzoni@...tlin.com
Subject: Re: [RFC 4/7] mfd: ocelot-spi: Change the regmap stride to reflect
 the real one

> > >  static const struct regmap_config ocelot_spi_regmap_config = {
> > >  	.reg_bits = 24,
> > > -	.reg_stride = 4,
> > > +	.reg_stride = 1,
> > >  	.reg_shift = REGMAP_DOWNSHIFT(2),
> > >  	.val_bits = 32,  
> > 
> > This does not look like a bisectable change? Or did it never work
> > before?
> 
> Actually this works in all cases because of "regmap: check for alignment
> on translated register addresses" in this series. Before this series,
> I think using a stride of 1 would have worked too, as any 4-byte-aligned
> accesses are also 1-byte aligned.

This is the sort of think which is good to explain in the commit
message. That is the place to answer questions reviewers are likely to
ask for things which are not obvious from just the patch.

    Andrew