From: David Brownell <david-b@pacbell.net>
To: avorontsov@ru.mvista.com
Cc: Greg Kroah-Hartman <greg@kroah.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
linuxppc-dev@ozlabs.org,
Andrew Morton <akpm@linux-foundation.org>,
Li Yang <leoli@freescale.com>, Timur Tabi <timur@freescale.com>
Subject: Re: [PATCH 2/4] powerpc/qe: new call to revert a gpio to a dedicated function
Date: Wed, 24 Sep 2008 11:54:59 -0700 [thread overview]
Message-ID: <200809241155.00814.david-b@pacbell.net> (raw)
In-Reply-To: <20080924114231.GA8469@oksana.dev.rtsoft.ru>
On Wednesday 24 September 2008, Anton Vorontsov wrote:
> > what do you mean by dedicated function.. be a bit clearer in the commit
> > log.
>
> This term is from the QE spec, I didn't invent anything. ;-)
>
> "Each pin in the I/O ports can be configured as a general-purpose
> I/O signal or as a dedicated peripheral interface signal. ...many
> dedicated peripheral functions are multiplexed onto the ports."
Which, to me, highlights the point I've made previously: the
right abstraction for you to work with is "pin", not GPIO.
You need to switch a QE "pin" from one of its roles to the other.
Evil things, like oopsing, will happen if you try to use this call
on a GPIO that's not backed by a QE pin.
WARNING: multiple messages have this Message-ID (diff)
From: David Brownell <david-b@pacbell.net>
To: avorontsov@ru.mvista.com
Cc: Kumar Gala <galak@kernel.crashing.org>,
Andrew Morton <akpm@linux-foundation.org>,
Greg Kroah-Hartman <greg@kroah.com>,
Timur Tabi <timur@freescale.com>, Li Yang <leoli@freescale.com>,
Laurent Pinchart <laurentp@cse-semaphore.com>,
linuxppc-dev@ozlabs.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] powerpc/qe: new call to revert a gpio to a dedicated function
Date: Wed, 24 Sep 2008 11:54:59 -0700 [thread overview]
Message-ID: <200809241155.00814.david-b@pacbell.net> (raw)
In-Reply-To: <20080924114231.GA8469@oksana.dev.rtsoft.ru>
On Wednesday 24 September 2008, Anton Vorontsov wrote:
> > what do you mean by dedicated function.. be a bit clearer in the commit
> > log.
>
> This term is from the QE spec, I didn't invent anything. ;-)
>
> "Each pin in the I/O ports can be configured as a general-purpose
> I/O signal or as a dedicated peripheral interface signal. ...many
> dedicated peripheral functions are multiplexed onto the ports."
Which, to me, highlights the point I've made previously: the
right abstraction for you to work with is "pin", not GPIO.
You need to switch a QE "pin" from one of its roles to the other.
Evil things, like oopsing, will happen if you try to use this call
on a GPIO that's not backed by a QE pin.
next prev parent reply other threads:[~2008-09-24 18:55 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-24 0:02 [PATCH 0/4] FHCI USB Host support patches Anton Vorontsov
2008-09-24 0:02 ` Anton Vorontsov
2008-09-24 0:03 ` [PATCH 1/4] gpiolib: make gpio_to_chip() public Anton Vorontsov
2008-09-24 0:03 ` Anton Vorontsov
2008-09-24 0:03 ` [PATCH 2/4] powerpc/qe: new call to revert a gpio to a dedicated function Anton Vorontsov
2008-09-24 0:03 ` Anton Vorontsov
2008-09-24 4:07 ` Kumar Gala
2008-09-24 4:07 ` Kumar Gala
2008-09-24 11:42 ` Anton Vorontsov
2008-09-24 11:42 ` Anton Vorontsov
2008-09-24 14:00 ` Kumar Gala
2008-09-24 14:00 ` Kumar Gala
2008-09-24 14:11 ` Anton Vorontsov
2008-09-24 14:11 ` Anton Vorontsov
2008-09-24 18:54 ` David Brownell [this message]
2008-09-24 18:54 ` David Brownell
2008-09-24 18:54 ` David Brownell
2008-09-24 18:54 ` David Brownell
2008-09-24 23:29 ` Anton Vorontsov
2008-09-24 23:29 ` Anton Vorontsov
2008-09-25 4:13 ` David Brownell
2008-09-25 4:13 ` David Brownell
2008-09-24 0:03 ` [PATCH 3/4] USB: Protect hcd.h from multiple inclusions Anton Vorontsov
2008-09-24 0:03 ` Anton Vorontsov
2008-09-24 3:35 ` David Brownell
2008-09-24 3:35 ` David Brownell
2008-09-24 0:03 ` [PATCH 4/4] USB: driver for Freescale QUICC Engine USB Host Controller Anton Vorontsov
2008-09-24 0:03 ` Anton Vorontsov
-- strict thread matches above, loose matches on Subject: below --
2008-09-24 18:20 [PATCH v3 0/4] FHCI USB Host support patches Anton Vorontsov
2008-09-24 18:21 ` [PATCH 2/4] powerpc/qe: new call to revert a gpio to a dedicated function Anton Vorontsov
2008-09-24 18:21 ` Anton Vorontsov
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