linux-kernel - Re: [PATCH v1 2/5] ASoC: cs35l56: Add struct to index firmware registers

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Message-ID: <f9fcff2f-34b6-4291-82d1-3b40c0f7e8e6@sirena.org.uk>
Date: Tue, 8 Apr 2025 17:00:53 +0100
From: Mark Brown <broonie@...nel.org>
To: Richard Fitzgerald <rf@...nsource.cirrus.com>
Cc: Stefan Binding <sbinding@...nsource.cirrus.com>,
	linux-sound@...r.kernel.org, linux-kernel@...r.kernel.org,
	patches@...nsource.cirrus.com
Subject: Re: [PATCH v1 2/5] ASoC: cs35l56: Add struct to index firmware
 registers

On Tue, Apr 08, 2025 at 01:58:23PM +0100, Richard Fitzgerald wrote:
> On 07/04/2025 8:16 pm, Mark Brown wrote:

> > This is fine but note that this is the use case that the regmap_field_
> > APIs were created for, that also helps deal with things if anyone is
> > clever and resizes fields or shifts within registers.  It's purely a
> > question of taste if you want to use that.

> The regmap_field stuff looks like a lot of unnecessary complexity and
> overhead just for 6 registers with alternate addresses.

Yeah, like I say it's a taste thing.

> (In fact, the regmap_field stuff looks like an over-complex way of
> solving a non-problem. The original commit is talking about replacing
> masks and shifts "all over the code" to make the code neater. But
> really, all those extra structs and pointers and allocated memory just
> to replace a logical & or | ? Every struct regmap_field has a pointer
> to the struct regmap !!?! So if I've got 100 fields there are 100 copies
> of the struct regmap pointer that my driver already has.)

It was for cases where the shifts and widths may also change, there's a
bit more than applying a mask.  Like you say it's got some overhead
hence the taste thing.

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