linux-kernel - Re: [RFC 4/4] gpio: sifive: Add GPIO driver for SiFive SoCs

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Date:   Wed, 10 Oct 2018 15:28:50 +0200
From:   Andreas Schwab <schwab@...e.de>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     Atish Patra <atish.patra@....com>, palmer@...ive.com,
        linux-riscv@...ts.infradead.org, linux-pwm@...r.kernel.org,
        linux-gpio@...r.kernel.org, linus.walleij@...aro.org,
        robh+dt@...nel.org, thierry.reding@...il.com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        mark.rutland@....com
Subject: Re: [RFC 4/4] gpio: sifive: Add GPIO driver for SiFive SoCs

On Okt 10 2018, Christoph Hellwig <hch@...radead.org> wrote:

> On Wed, Oct 10, 2018 at 03:01:29PM +0200, Andreas Schwab wrote:
>> On Okt 09 2018, Atish Patra <atish.patra@....com> wrote:
>> 
>> > +static void sifive_set_ie(struct sifive_gpio *chip, unsigned int offset)
>> > +{
>> > +	unsigned long flags;
>> > +	unsigned int trigger;
>> > +
>> > +	raw_spin_lock_irqsave(&chip->lock, flags);
>> > +	trigger = (chip->enabled & BIT(offset)) ? chip->trigger[offset] : 0;
>> 
>> This should use test_bit instead.
>
> Given that this apparently needs the spinlock for atomciy with more than
> just the bitmap test_bit would be rather pointless.

BIT and test_bit/assign_bit are not compatible.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@...e.de
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