From: Janek Kotas <jank@cadence.com>
To: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Janek Kotas <jank@cadence.com>, Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-gpio <linux-gpio@vger.kernel.org>,
linux-devicetree <devicetree@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver
Date: Tue, 18 Dec 2018 13:54:25 +0000 [thread overview]
Message-ID: <220ECBA7-CD30-4221-8878-0DA93390DDCC@global.cadence.com> (raw)
In-Reply-To: <CAMpxmJUnfnHmopyOfHRZrN1KoqZx_Bsra1BTiGud6UVmzz1ryA@mail.gmail.com>
> On 18 Dec 2018, at 13:50, Bartosz Golaszewski <bgolaszewski@baylibre.com> wrote:
>
>
> pon., 17 gru 2018 o 23:22 Linus Walleij <linus.walleij@linaro.org> napisał(a):
>>
>> On Mon, Dec 17, 2018 at 4:51 PM Bartosz Golaszewski
>> <bgolaszewski@baylibre.com> wrote:
>>
>>> The driver looks good but is there any particular reason not to use
>>> regmap for register IO?
>>
>> I thought we only use regmap for MMIO when the register range is
>> shared (as in a system controller) so that some registers are for this,
>> some register or even bits in a register for some other driver, so they
>> need the spinlock in the regmap to protect the register range.
>>
>
> This is what syscon is for. Regmap simply abstracts any register IO.
> For instance: there's no locking in this driver. Are we sure it's not
> needed? Regmap provides internal locking for you in the form of a
> mutex or spinlock.
>
> Also: it looks like the interrupts here are quite simple with a single
> bit per interrupt in the status register and the same layout in the
> mask register - it could probably profit from using the
> regmap_irq_chip and not bother with reimplementing irq_chip callbacks.
>
>> It is also nice for shadowing/caching of register contents I guess,
>> wat does this driver get from regmap MMIO?
>>
>
> Code shrinkage IMO.
>
> Note that I'm not blocking this from being merged - I just think that
> using modern frameworks is always a good idea.
I can reimplement the driver using regmap, but It seems in such case
I won’t be able to use the Generic GPIO Infrastructure, would I?
So I would need to provide functions for setting direction, etc.
I think it would make the driver code bigger.
Regards,
Jan
> Best regards,
> Bartosz Golaszewski
>
>> Yours,
>> Linus Walleij
next prev parent reply other threads:[~2018-12-18 13:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-17 15:36 [PATCH v2 0/2] gpio: Add a driver for Cadence GPIO controller Jan Kotas
2018-12-17 15:36 ` [PATCH v2 1/2] dt-bindings: gpio: Add bindings for Cadence GPIO Jan Kotas
2018-12-18 17:33 ` Rob Herring
2018-12-17 15:36 ` [PATCH v2 2/2] gpio: Add Cadence GPIO driver Jan Kotas
2018-12-17 15:51 ` Bartosz Golaszewski
2018-12-17 22:21 ` Linus Walleij
2018-12-18 12:50 ` Bartosz Golaszewski
2018-12-18 13:54 ` Janek Kotas [this message]
2018-12-18 14:06 ` Bartosz Golaszewski
2018-12-21 10:37 ` Linus Walleij
2018-12-21 10:34 ` Linus Walleij
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=220ECBA7-CD30-4221-8878-0DA93390DDCC@global.cadence.com \
--to=jank@cadence.com \
--cc=bgolaszewski@baylibre.com \
--cc=devicetree@vger.kernel.org \
--cc=linus.walleij@linaro.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=robh+dt@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).