From: Linus Walleij <linus.walleij@linaro.org>
To: David Daney <ddaney@caviumnetworks.com>
Cc: David Daney <ddaney.cavm@gmail.com>,
Alexandre Courbot <gnurou@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
David Daney <david.daney@cavium.com>,
Marc Zyngier <marc.zyngier@arm.com>
Subject: Re: [PATCH v2 2/3] gpio: Add gpio driver support for ThunderX and OCTEON-TX
Date: Wed, 11 Jan 2017 16:07:24 +0100 [thread overview]
Message-ID: <CACRpkdYDM4EnyumV0_Sq+_QWq=mBRMEFayb5E+ZycYnrfuxcKA@mail.gmail.com> (raw)
In-Reply-To: <245af7b3-cfb7-e606-f1b8-f68b2ec0b8d1@caviumnetworks.com>
On Mon, Jan 9, 2017 at 9:02 PM, David Daney <ddaney@caviumnetworks.com> wrote:
>> if (test_bit(line, gpio->invert_mask))
>> return !(read_bits & BIT(bank_bit));
>> else
>> return !!(read_bits & BIT(bank_bit));
>>
>> OK maybe not much clearer but seems clearer to me.
>
> As I really dislike the "!!" idiom, would you settle for:
>
> if (test_bit(line, gpio->invert_mask))
> return (read_bits & BIT(bank_bit)) == 0;
> else
> return (read_bits & BIT(bank_bit)) != 0;
Not the biggest issue in the world. But I maintain a huge stack
of GPIO drivers and it drives me crazy that each one has to bear
the mark of the authors habits rather than mine.
>> I think this is overkill. Use hierarchical irqdomain.
>
> I will look into it. I suspect it will require more lines of driver code to
> implement it than what I have here (that does actually work).
I understand. But at the same time, the kernel needs to have the
right idea of what it is dealing with here.
The generic IRQ handling code will take a shorter fastpath if
you are using hierarchical irqdomain (I think?) but I can't claim
to be an expert. When in doubt, consult Marc Z.
Yours,
Linus Walleij
next prev parent reply other threads:[~2017-01-11 15:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-06 23:22 [PATCH v2 0/3] GPIO: Add driver for ThunderX and OCTEON-TX SoCs David Daney
2017-01-06 23:22 ` [PATCH v2 1/3] dt-bindings: gpio: Add binding documentation for gpio-thunderx David Daney
2017-01-09 19:36 ` Linus Walleij
2017-01-09 19:44 ` David Daney
2017-01-10 8:42 ` Linus Walleij
2017-01-10 5:35 ` Rob Herring
2017-01-06 23:22 ` [PATCH v2 2/3] gpio: Add gpio driver support for ThunderX and OCTEON-TX David Daney
2017-01-09 19:35 ` Linus Walleij
2017-01-09 20:02 ` David Daney
2017-01-11 15:07 ` Linus Walleij [this message]
2017-01-06 23:23 ` [PATCH v2 3/3] MAINTAINERS: Add entry for THUNDERX GPIO Driver David Daney
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