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From: Johan Hovold <johan@kernel.org>
To: Octavian Purdila <octavian.purdila@intel.com>
Cc: Johan Hovold <johan@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Alexandre Courbot <gnurou@gmail.com>,
	wsa@the-dreams.de, Samuel Ortiz <sameo@linux.intel.com>,
	Lee Jones <lee.jones@linaro.org>, Arnd Bergmann <arnd@arndb.de>,
	Daniel Baluta <daniel.baluta@intel.com>,
	Laurentiu Palcu <laurentiu.palcu@intel.com>,
	linux-usb@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>,
	linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org
Subject: Re: [PATCH v4 3/3] gpio: add support for the Diolan DLN-2 USB GPIO driver
Date: Thu, 18 Sep 2014 14:46:11 +0200	[thread overview]
Message-ID: <20140918124611.GA26817@localhost> (raw)
In-Reply-To: <CAE1zot+_hX6TVkW-B6H9NzgyLhF54oQJZt+x_xXGjEB6A5dAZA@mail.gmail.com>

On Thu, Sep 18, 2014 at 03:43:07PM +0300, Octavian Purdila wrote:
> On Thu, Sep 18, 2014 at 1:54 PM, Johan Hovold <johan@kernel.org> wrote:
> > On Tue, Sep 09, 2014 at 10:24:46PM +0300, Octavian Purdila wrote:

> > Either way, it looks like this could race with get_direction() if you
> > get a set_direction() while get_direction() is retrieving the direction
> > from the device.
> >
> > This would break gpio_get().
> >
> I don't think gpio_set_direction() and gpio_get() are allowed to race.

I wrote that set_direction() and get_direction() could race, which in
turn would break gpio_get() as you would be caching the wrong
direction setting.

But perhaps gpiolib prevents this from happening.

Johan

  reply	other threads:[~2014-09-18 12:48 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-09 19:24 [PATCH v4 0/3] mfd: add support for Diolan DLN-2 Octavian Purdila
2014-09-09 19:24 ` [PATCH v4 1/3] mfd: add support for Diolan DLN-2 devices Octavian Purdila
2014-09-16 23:21   ` Lee Jones
2014-09-17  7:25     ` Octavian Purdila
2014-09-17  7:38       ` Johan Hovold
2014-09-17 15:56       ` Lee Jones
2014-09-17  9:10   ` Johan Hovold
2014-09-17 15:46     ` Lee Jones
2014-09-18 11:31   ` Johan Hovold
2014-09-18 14:21   ` Johan Hovold
2014-09-09 19:24 ` [PATCH v4 2/3] i2c: add support for Diolan DLN-2 USB-I2C adapter Octavian Purdila
2014-09-17  9:44   ` Johan Hovold
2014-09-17 10:07     ` Octavian Purdila
2014-09-18  8:19       ` Johan Hovold
2014-09-18  8:49         ` Octavian Purdila
2014-09-18  9:13           ` Johan Hovold
2014-09-09 19:24 ` [PATCH v4 3/3] gpio: add support for the Diolan DLN-2 USB GPIO driver Octavian Purdila
2014-09-18 10:54   ` Johan Hovold
2014-09-18 12:43     ` Octavian Purdila
2014-09-18 12:46       ` Johan Hovold [this message]
2014-09-18 15:54         ` Octavian Purdila
2014-09-19  7:11           ` Johan Hovold

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