From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Tue, 19 Apr 2016 22:19:58 +0100
Subject: [PATCH] ARM: imx25-pinfunc: remove SION from all modes
In-Reply-To: <1461095114-11745-1-git-send-email-u.kleine-koenig@pengutronix.de>
References: <1461095114-11745-1-git-send-email-u.kleine-koenig@pengutronix.de>
Message-ID: <20160419211958.GD19428@n2100.arm.linux.org.uk>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Apr 19, 2016 at 09:45:14PM +0200, Uwe Kleine-K?nig wrote:
> With the SION bit set a pin can be read as GPIO even though it's not muxed
> as GPIO. This is useful at times. The downside however is that the signal
> is not only routed to the GPIO IP but also all other IPs that can make use
> of the pin. This resulted in more than one issue for me in the past. Things
> like spi transfers that result in usb reenumeration or setting a GPIO to a
> value that triggers an RTS irq for an UART.

Isn't SION required for all GPIOs such that reading the value of a GPIO
pin returns the actual state of the pin, not the output value written
to it?

What about the ethernet pins?  I know that on iMX6, SION is required for
correct functionality of certain phy clocking modes, and I wouldn't be
surprised if this was true in earlier designs as well.

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