linux-kernel - Re: [PATCH v1 4/5] gpio: xilinx: Switch to use bitmap APIs

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Message-ID: <YG8cWBkcF8ulHW0D@smile.fi.intel.com>
Date:   Thu, 8 Apr 2021 18:08:08 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     linux-gpio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     Shubhrajyoti Datta <shubhrajyoti.datta@...inx.com>,
        Srinivas Neeli <srinivas.neeli@...inx.com>,
        Michal Simek <michal.simek@...inx.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Yury Norov <yury.norov@...il.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Syed Nayyar Waris <syednwaris@...il.com>,
        vilhelm.gray@...il.com
Subject: Re: [PATCH v1 4/5] gpio: xilinx: Switch to use bitmap APIs

On Thu, Apr 08, 2021 at 05:56:00PM +0300, Andy Shevchenko wrote:
> It seems that Xilinx GPIO driver operates with bit arrays longer than 32 and
> thus can leverage bitmap APIs for that. It makes code better to understand.
> 
> The ->probe() function is modified to try read properties for both channels
> since is_dual check makes only sense for the amount of pins used for the second
> channel. On top of that kzalloc() guarantees zero initial values for the fields
> in the private data structure, hence drop unneeded conditionals and assignments.
> 
> The change is inspired by Syed Nayyar Waris' ideas about bitmap API extension.

As I was afraid in the cover letter, I found some mistakes already.
In any case, I'll wait for the comments and test of other patches if possible.

Out of curiosity, below I point out the issues.

...

> +	return bitmap_bitremap(gpio, chip->sw_map, chip->hw_map, chip->gc.ngpio);

Seems we have to use 64 instead of ngpio here.

...

> +	bitmap_replace(state, chip->state, hw_bits, hw_mask, gc->ngpio);

Ditto.

...

> +	bitmap_copy(chip->state, state, gc->ngpio);

Ditto.

...

> +	for_each_set_bit(bit, all, 64)
> +		generic_handle_irq(irq_find_mapping(gc->irq.domain, bit));

Here should be used gpio actually and ngpio IIUC.

-- 
With Best Regards,
Andy Shevchenko