linux-kernel - Re: [PATCH v4 6/7] gpio: exar: switch to using regmap

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Message-ID: <20201110151022.GY4077@smile.fi.intel.com>
Date:   Tue, 10 Nov 2020 17:10:22 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Jan Kiszka <jan.kiszka@...mens.com>,
        David Laight <David.Laight@...lab.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v4 6/7] gpio: exar: switch to using regmap

On Tue, Nov 10, 2020 at 05:04:47PM +0200, Andy Shevchenko wrote:
> On Tue, Nov 10, 2020 at 03:55:51PM +0100, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > 
> > We can simplify the code in gpio-exar by using regmap. This allows us to
> > drop the mutex (regmap provides its own locking) and we can also reuse
> > regmap's bit operations instead of implementing our own update function.
> 
> ...
> 
> > +static const struct regmap_config exar_regmap_config = {
> > +	.name		= "exar-gpio",
> > +	.reg_bits	= 16,
> 
> As per previous version comment.
> 
> Hold on, the registers are 16-bit wide, but their halves are sparsed!
> So, I guess 8 and 8 with helpers to get hi and lo parts are essential.
> 
> 
> TABLE 5: DEVICE CONFIGURATION REGISTERS SHOWN IN BYTE ALIGNMENT
> 
> > +	.val_bits	= 8,
> > +};
> 
> This is basically represents two banks out of 6 8-bit registers each.

...which makes me wonder if gpio-regmap can be utilized here...

-- 
With Best Regards,
Andy Shevchenko