Re: [stable] [PATCH] cs5535-gpio: apply CS5536 errata workaroundfor GPIOs

From: Greg KH
Date: Mon Nov 29 2010 - 22:37:52 EST


On Mon, Nov 29, 2010 at 05:19:30PM -0800, Andres Salomon wrote:
>
> The AMD Geode CS5536 Companion Device Silicon Revision B1 Specification Update
> mentions the follow as issue #36:
>
> "Atomic write transactions to the atomic GPIO High Bank Feature Bit registers
> should only affect the bits selected [...]"
> "after Suspend, an atomic write transaction [...] will clear all non-selected
> bits of the accessed register."
>
> In other words, writing to the high bank for a single GPIO bit will clear
> every other GPIO bit (but only sometimes after a suspend). The workaround
> described is obvious and simple; do a read-modify-write. This patch does
> that, and documents why we're doing it.
>
> Signed-off-by: Andres Salomon <dilinger@xxxxxxxxxx>

Please read Documentation/stable_kernel_rules.txt for how to get patches
into the stable kernel releases (hint, this wasn't the proper way...)

thanks,

greg k-h
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