Re: PCF857x and 16-bit GPIO expanders

From: Felipe Balbi
Date: Thu Sep 19 2013 - 08:46:08 EST


Hi,

On Thu, Sep 19, 2013 at 01:43:41PM +0530, George Cherian wrote:
> On 9/18/2013 11:06 PM, Felipe Balbi wrote:
> >Hi,
> >
> >On Wed, Sep 18, 2013 at 07:18:04PM +0200, Laurent Pinchart wrote:
> >>On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
> >>>On Tue, Sep 17, 2013 at 9:07 PM, Felipe Balbi <balbi@xxxxxx> wrote:
> >>>>has anyone ever successfully using gpio-pcf857x.c driver with 16-bit
> >>>>gpio expanders ? We're having some issues here where toggling the last
> >>>>gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I
> >>>>can't come up with any explanation of why would it hang...
> >>>Bouncing the question to George, Laurent and Kuninori...
> >>I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as
> >>I know.
> >>
> >>I can try toggling I/O 15, but that will need to wait until next week as I'm
> >>currently travelling without access to the hardware.
> >alright, that'd help me a lot :-) Just want to make sure if we're having
> >a board issue, or PCF8575 is a bit screwy ;-)
> Is it on dra7x-evm if so which pcf device (i2c address)?

0x21 IIRC, it's pin 15 on that goes to a discrete mux. I want to toggle
the mux ;-)

--
balbi

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