Documentation: gpiolib: sysfs: high can be any nonzero value
diff mbox

Message ID 1429720786-6277-1-git-send-email-dirk.behme@gmail.com
State New
Headers show

Commit Message

Dirk Behme April 22, 2015, 4:39 p.m. UTC
With the commit 79a9becda8940d ("gpiolib: export descriptor-based
GPIO interface") the gpiolib can return any nonzero value for high.
Not only 1. Correct this in the documentation.

Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
---

Note: Commit 79a9becda8940d has been merged in v3.13. If this
      patch is considered to be fine, please think about applying
      it to -stable >= v3.14, too.

 Documentation/gpio/sysfs.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Johan Hovold April 22, 2015, 5:10 p.m. UTC | #1
On Wed, Apr 22, 2015 at 06:39:46PM +0200, Dirk Behme wrote:
> With the commit 79a9becda8940d ("gpiolib: export descriptor-based
> GPIO interface") the gpiolib can return any nonzero value for high.
> Not only 1. Correct this in the documentation.

As _gpiod_get_raw_value returns a bool, I fail to see how that could
happen.

Ah, that was fixed by commit 23600969ff13 ("gpio: clamp returned values
to the boolean range") in 3.15.

Looks like that one should be backported to 3.14 instead.

Thanks,
Johan
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Vladimir Zapolskiy April 22, 2015, 9:12 p.m. UTC | #2
Hi Greg,

On 22.04.2015 20:10, Johan Hovold wrote:
> On Wed, Apr 22, 2015 at 06:39:46PM +0200, Dirk Behme wrote:
>> With the commit 79a9becda8940d ("gpiolib: export descriptor-based
>> GPIO interface") the gpiolib can return any nonzero value for high.
>> Not only 1. Correct this in the documentation.
> 
> As _gpiod_get_raw_value returns a bool, I fail to see how that could
> happen.
> 
> Ah, that was fixed by commit 23600969ff13 ("gpio: clamp returned values
> to the boolean range") in 3.15.
> 
> Looks like that one should be backported to 3.14 instead.
> 

I tested that 23600969ff13 clearly applies to 3.14.y and I confirm that
it fixes the problem.

Would it be possible for you to backport this commit to LTS 3.14.y,
since it fixes quite critical sysfs API regression? Or should I send the
patch to stable@vger.kernel.org ?

Thank you in advance!

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With best wishes,
Vladimir
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Greg Kroah-Hartman May 2, 2015, 4:36 p.m. UTC | #3
On Thu, Apr 23, 2015 at 12:12:46AM +0300, Vladimir Zapolskiy wrote:
> Hi Greg,
> 
> On 22.04.2015 20:10, Johan Hovold wrote:
> > On Wed, Apr 22, 2015 at 06:39:46PM +0200, Dirk Behme wrote:
> >> With the commit 79a9becda8940d ("gpiolib: export descriptor-based
> >> GPIO interface") the gpiolib can return any nonzero value for high.
> >> Not only 1. Correct this in the documentation.
> > 
> > As _gpiod_get_raw_value returns a bool, I fail to see how that could
> > happen.
> > 
> > Ah, that was fixed by commit 23600969ff13 ("gpio: clamp returned values
> > to the boolean range") in 3.15.
> > 
> > Looks like that one should be backported to 3.14 instead.
> > 
> 
> I tested that 23600969ff13 clearly applies to 3.14.y and I confirm that
> it fixes the problem.
> 
> Would it be possible for you to backport this commit to LTS 3.14.y,
> since it fixes quite critical sysfs API regression? Or should I send the
> patch to stable@vger.kernel.org ?

Normally always send this type of thing to stable@vger, but I've now
picked it up, thanks.

greg k-h
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Patch
diff mbox

diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt
index c2c3a97..bc7f31d 100644
--- a/Documentation/gpio/sysfs.txt
+++ b/Documentation/gpio/sysfs.txt
@@ -69,7 +69,7 @@  and have the following read/write attributes:
 		it was exported by kernel code that didn't explicitly
 		allow userspace to reconfigure this GPIO's direction.
 
-	"value" ... reads as either 0 (low) or 1 (high). If the GPIO
+	"value" ... reads as either 0 (low) or nonzero (high). If the GPIO
 		is configured as an output, this value may be written;
 		any nonzero value is treated as high.