linux-kernel - Re: [PATCH 3/4] gpio: tqmx86: introduce tqmx86_gpio

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Message-ID: <4ea6c6b1-fe2d-445d-8e8a-b00c3c2584ad@sirena.org.uk>
Date: Fri, 20 Dec 2024 13:57:24 +0000
From: Mark Brown <broonie@...nel.org>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: Matthias Schiffer <matthias.schiffer@...tq-group.com>,
	Bartosz Golaszewski <brgl@...ev.pl>, linux@...tq-group.com,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] gpio: tqmx86: introduce tqmx86_gpio_clrsetbits()
 helper

On Fri, Dec 20, 2024 at 02:43:15PM +0100, Linus Walleij wrote:

> I don't see why we can't add
> unsigned in regmap_read_cantfail()
> that always just return the value if this is a common problem for people using
> regmap MMIO specifically? Could perhaps be restricted to mmio.

I can't recall people ever having much problem with just ignoring the
return value if they don't care about it.

> > - I introduced a tqmx86_gpio_clrsetbits() wrapper around regmap_update_bits()
> >   (having arguments for set and clear was more convenient than mask and value
> >    in a few places)

> Isn't that what regmap fields are for?
> regmap_field_set_bits()
> regmap_field_clear_bits()

The field API is more for and indirection where bitfields move about,
but there are top level set and clear operations too.

> > - I was still handling locking outside of regmap because we sometimes want to
> >   protect a whole sequence of accesses or other driver state

> So reg_sequence cannot be used in this case? (Other driver state seems
> to imply that.)

Yes, regmap_multi_reg_write() does what it says on the tin.

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