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

From: Maxime Chevallier <maxime.chevallier@bootlin.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Mark Brown <broonie@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	rafael@kernel.org, Colin Foster <colin.foster@in-advantage.com>,
	Vladimir Oltean <vladimir.oltean@nxp.com>,
	Lee Jones <lee@kernel.org>,
	davem@davemloft.net, Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	thomas.petazzoni@bootlin.com
Subject: Re: [RFC 4/7] mfd: ocelot-spi: Change the regmap stride to reflect the real one
Date: Thu, 30 Mar 2023 11:46:31 +0200	[thread overview]
Message-ID: <20230330114631.6afa041c@pc-7.home> (raw)
In-Reply-To: <826e295b-6a0b-4015-85bc-5ba6015678dc@lunn.ch>

Hello Andrew,

On Mon, 27 Mar 2023 02:02:55 +0200
Andrew Lunn <andrew@lunn.ch> wrote:

> > > >  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.

That's right, I will include this explanation in the next iteration.
Thanks for the review,

Maxime

>     Andrew