From: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
To: Dmitry Eremin-Solenikov
<dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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Jingoo
Subject: Re: [PATCH 02/15] GPIO: port LoCoMo gpio support from old driver
Date: Mon, 3 Nov 2014 14:43:21 +0100 [thread overview]
Message-ID: <CACRpkdb7v3LmOhbhQ9TPk1_bnLnpwizawW6RQvhQRLSjRewAaQ@mail.gmail.com> (raw)
In-Reply-To: <CALT56yOgMUA7o2dzfHph=S2zkDV4zERzMh4ishpPwpAx7Cqj6Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Fri, Oct 31, 2014 at 10:39 AM, Dmitry Eremin-Solenikov
<dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> 2014-10-31 10:48 GMT+03:00 Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>:
>> On Tue, Oct 28, 2014 at 1:01 AM, Dmitry Eremin-Solenikov
>> <dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>
>>> Add gpiolib driver for gpio pins placed on the LoCoMo GA.
>>>
>>> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>>
>
> [skipped]
>
>> (etc, everywhere this pattern occurs).
>>> +static void locomo_gpio_set(struct gpio_chip *chip,
>>> + unsigned offset, int value)
>>> +{
>>> + struct locomo_gpio *lg = container_of(chip, struct locomo_gpio, gpio);
>>> + unsigned long flags;
>>> +
>>> + spin_lock_irqsave(&lg->lock, flags);
>>> +
>>> + __locomo_gpio_set(chip, offset, value);
>>> +
>>> + spin_unlock_irqrestore(&lg->lock, flags);
>>
>> If you actually always have to be getting and releasing a spin lock around
>> the register writes, contemplate using regmap-mmio because that
>> is part of what it does.
>>
>> But is this locking really necessary?
>
> I have a custom of doing such locking and never having to think about
> somebody breaking into RMW cycles.
>
> Also isn't regmap an overkill here? Wouldn't regmap also do a lock/unlock
> around each register read/write/RMW?
Yes that's the point: if you use regmap mmio you get the RMW-locking
for free, with the regmap implementation.
Yours,
Linus Walleij
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next prev parent reply other threads:[~2014-11-03 13:43 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-28 0:01 [PATCH 00/15] new locomo driver Dmitry Eremin-Solenikov
2014-10-28 0:01 ` [PATCH 01/15] mfd: add new driver for Sharp LoCoMo Dmitry Eremin-Solenikov
[not found] ` <1414454528-24240-2-git-send-email-dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-10-31 7:42 ` Linus Walleij
2014-10-31 9:54 ` Dmitry Eremin-Solenikov
[not found] ` <CALT56yNX8v4mZn=o1ZoVLHPmg6wq0dgFNowpqNuFtU=eCc+d8w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-03 13:41 ` Linus Walleij
2014-11-05 20:02 ` Dmitry Eremin-Solenikov
2014-11-05 20:24 ` Mark Brown
2014-11-14 12:47 ` Dmitry Eremin-Solenikov
2014-11-14 15:10 ` Mark Brown
2014-11-14 15:30 ` Dmitry Eremin-Solenikov
2014-11-05 20:32 ` Lars-Peter Clausen
2014-11-05 20:42 ` Lars-Peter Clausen
2014-10-28 0:01 ` [PATCH 02/15] GPIO: port LoCoMo gpio support from old driver Dmitry Eremin-Solenikov
2014-10-31 7:48 ` Linus Walleij
[not found] ` <CACRpkdY7tRadod2vQfEytmw-ubaMAvr_=XTczD5bUMkqie0xkg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-31 9:39 ` Dmitry Eremin-Solenikov
[not found] ` <CALT56yOgMUA7o2dzfHph=S2zkDV4zERzMh4ishpPwpAx7Cqj6Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-03 13:43 ` Linus Walleij [this message]
[not found] ` <CACRpkdb7v3LmOhbhQ9TPk1_bnLnpwizawW6RQvhQRLSjRewAaQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-05 21:33 ` Dmitry Eremin-Solenikov
2014-11-06 6:03 ` Mark Brown
2014-11-11 13:16 ` Dmitry Eremin-Solenikov
[not found] ` <CALT56yPr42FV66USngocw=eWPt81d5R2MJxmzBnv02HOMmXAkA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-11-11 13:23 ` Mark Brown
2014-11-14 10:11 ` Linus Walleij
2014-11-14 12:48 ` Dmitry Eremin-Solenikov
2014-10-28 0:01 ` [PATCH 03/15] leds: port locomo leds driver to new locomo core Dmitry Eremin-Solenikov
[not found] ` <1414454528-24240-1-git-send-email-dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-10-28 0:01 ` [PATCH 04/15] input: convert LoCoMo keyboard driver to use " Dmitry Eremin-Solenikov
2014-10-28 0:09 ` Dmitry Torokhov
2014-10-28 0:02 ` [PATCH 08/15] ARM: sa1100: make collie use new locomo drivers Dmitry Eremin-Solenikov
2014-10-28 0:02 ` [PATCH 12/15] ARM: pxa: poodle: don't preallocate IRQ space for locomo Dmitry Eremin-Solenikov
2014-10-28 19:13 ` Robert Jarzmik
2014-10-28 0:02 ` [PATCH 13/15] ARM: drop old LoCoMo driver Dmitry Eremin-Solenikov
2014-10-28 0:02 ` [PATCH 14/15] gpio: locomo: implement per-pin irq handling Dmitry Eremin-Solenikov
2014-10-31 8:00 ` Linus Walleij
2014-10-31 9:35 ` Dmitry Eremin-Solenikov
2014-10-28 0:02 ` [PATCH 15/15] spi: add locomo SPI driver Dmitry Eremin-Solenikov
[not found] ` <1414454528-24240-16-git-send-email-dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-10-28 11:03 ` Mark Brown
2014-10-28 0:01 ` [PATCH 05/15] video: backlight: add new locomo backlight driver Dmitry Eremin-Solenikov
2014-10-28 0:24 ` Jingoo Han
2014-10-28 0:01 ` [PATCH 06/15] video: lcd: add LoCoMo LCD driver Dmitry Eremin-Solenikov
2014-10-28 0:30 ` Jingoo Han
2014-10-28 16:47 ` Dmitry Eremin-Solenikov
2014-10-28 0:02 ` [PATCH 07/15] video: backlight: drop old locomo bl/lcd driver Dmitry Eremin-Solenikov
2014-10-28 0:02 ` [PATCH 09/15] ARM: sa1100: don't preallocate IRQ space for locomo Dmitry Eremin-Solenikov
2014-10-31 7:50 ` Linus Walleij
2014-10-31 9:33 ` Dmitry Eremin-Solenikov
2014-10-28 0:02 ` [PATCH 10/15] ARM: pxa: poodle: use new LoCoMo driver Dmitry Eremin-Solenikov
2014-10-28 0:02 ` [PATCH 11/15] sound: soc: poodle: make use of new locomo GPIO interface Dmitry Eremin-Solenikov
[not found] ` <1414454528-24240-12-git-send-email-dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-10-28 14:58 ` Mark Brown
[not found] ` <20141028145850.GU18557-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2014-10-28 16:45 ` Dmitry Eremin-Solenikov
2014-10-29 3:03 ` Alexandre Courbot
[not found] ` <CAAVeFuKgARoMFzf+663iP6cULs93d4WSQS8ESjUb9VcxguWurA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-31 9:52 ` Linus Walleij
2014-10-31 9:58 ` Dmitry Eremin-Solenikov
2014-11-01 5:42 ` Alexandre Courbot
2014-10-28 0:13 ` [PATCH 00/15] new locomo driver Russell King - ARM Linux
[not found] ` <20141028001338.GZ27405-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2014-10-28 0:28 ` Dmitry Eremin-Solenikov
2014-10-28 0:29 ` Mark Brown
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