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From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3.9] Driver for 7-segment displays connected over GPIOs
Date: Mon, 7 Jan 2013 18:43:52 +0100	[thread overview]
Message-ID: <20130107184352.2e90abfb@skate> (raw)
In-Reply-To: <20130107184022.72b23aa9@skate>


On Mon, 7 Jan 2013 18:40:22 +0100, Thomas Petazzoni wrote:

> > > Not having a kernel driver means that gazillions of applications
> > > re-invent the same piece of code over and over again, have to hardcode
> > > the GPIO numbers for a given piece of hardware, while the kernel
> > > abstract all of this very nicely.
> > 
> > That sounds like a wonderful use of a userspace library to do this
> > properly.  Much like libusb does, right?
> > 
> > I still think as this can be done in userspace, it probably should be.
> 
> Understood. Patches discarded.

Thinking more about this. How would your userspace library know on which
GPIOs your 7-seg segment device is connected? Should it parse the
Device Tree from userspace? Given by the user-space application who
would have to hardcode the GPIO numbers, completely defeating the
hardware abstraction layer that the kernel intends to be?

Thanks,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

WARNING: multiple messages have this Message-ID (diff)
From: Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Greg Kroah-Hartman
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
Cc: Lior Amsalem <alior-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>,
	Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>,
	Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>,
	devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH 3.9] Driver for 7-segment displays connected over GPIOs
Date: Mon, 7 Jan 2013 18:43:52 +0100	[thread overview]
Message-ID: <20130107184352.2e90abfb@skate> (raw)
In-Reply-To: <20130107184022.72b23aa9@skate>


On Mon, 7 Jan 2013 18:40:22 +0100, Thomas Petazzoni wrote:

> > > Not having a kernel driver means that gazillions of applications
> > > re-invent the same piece of code over and over again, have to hardcode
> > > the GPIO numbers for a given piece of hardware, while the kernel
> > > abstract all of this very nicely.
> > 
> > That sounds like a wonderful use of a userspace library to do this
> > properly.  Much like libusb does, right?
> > 
> > I still think as this can be done in userspace, it probably should be.
> 
> Understood. Patches discarded.

Thinking more about this. How would your userspace library know on which
GPIOs your 7-seg segment device is connected? Should it parse the
Device Tree from userspace? Given by the user-space application who
would have to hardcode the GPIO numbers, completely defeating the
hardware abstraction layer that the kernel intends to be?

Thanks,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

  reply	other threads:[~2013-01-07 17:43 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-07 16:42 [PATCH 3.9] Driver for 7-segment displays connected over GPIOs Thomas Petazzoni
2013-01-07 16:42 ` Thomas Petazzoni
2013-01-07 16:42 ` [PATCH 3.9 1/3] misc: new driver for GPIO-connected 7-segment displays Thomas Petazzoni
2013-01-07 16:42   ` Thomas Petazzoni
2013-01-07 19:43   ` Arnd Bergmann
2013-01-07 19:43     ` Arnd Bergmann
2013-01-07 19:58     ` Thomas Petazzoni
2013-01-07 19:58       ` Thomas Petazzoni
2013-01-07 21:41       ` Arnd Bergmann
2013-01-07 21:41         ` Arnd Bergmann
2013-02-08 22:38         ` Grant Likely
2013-02-08 22:38           ` Grant Likely
2013-02-08 22:35   ` Grant Likely
2013-02-08 22:35     ` Grant Likely
2013-01-07 16:42 ` [PATCH 3.9 2/3] arm: mvebu: add the 7-segment display DT informations to Armada 370 DB Thomas Petazzoni
2013-01-07 16:42   ` Thomas Petazzoni
2013-01-07 16:42 ` [PATCH 3.9 3/3] arm: mvebu: add the 7-segment display DT informations to Armada XP DB Thomas Petazzoni
2013-01-07 16:42   ` Thomas Petazzoni
2013-02-08 22:39   ` Grant Likely
2013-02-08 22:39     ` Grant Likely
2013-01-07 16:48 ` [PATCH 3.9] Driver for 7-segment displays connected over GPIOs Greg Kroah-Hartman
2013-01-07 16:48   ` Greg Kroah-Hartman
2013-01-07 17:07   ` Thomas Petazzoni
2013-01-07 17:07     ` Thomas Petazzoni
2013-01-07 17:23     ` Greg Kroah-Hartman
2013-01-07 17:23       ` Greg Kroah-Hartman
2013-01-07 17:40       ` Thomas Petazzoni
2013-01-07 17:40         ` Thomas Petazzoni
2013-01-07 17:43         ` Thomas Petazzoni [this message]
2013-01-07 17:43           ` Thomas Petazzoni
2013-01-07 17:56           ` H Hartley Sweeten
2013-01-07 17:56             ` H Hartley Sweeten
2013-01-07 18:02             ` Jason Cooper
2013-01-07 18:02               ` Jason Cooper
2013-01-07 18:06           ` Russell King - ARM Linux
2013-01-07 18:06             ` Russell King - ARM Linux
2013-01-07 17:53       ` Thomas Petazzoni
2013-01-07 17:53         ` Thomas Petazzoni
2013-01-07 18:36         ` Greg Kroah-Hartman
2013-01-07 18:36           ` Greg Kroah-Hartman
2013-01-07 18:38           ` Thomas Petazzoni
2013-01-07 18:38             ` Thomas Petazzoni
2013-01-07 23:05 ` Linus Walleij
2013-01-07 23:05   ` Linus Walleij
2013-02-09 16:28   ` Pavel Machek
2013-02-09 16:28     ` Pavel Machek

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