Re: Floating inputs on unused GPIO pins

[Laurent Pinchart <laurentp@cse-semaphore.com>]

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Hi Leon,

sorry for the late reply.

On Monday 13 October 2008, Leon Woestenberg wrote:
> Hello Laurent,
> 
> On Mon, Oct 13, 2008 at 3:12 PM, Bill Gatliff <bgat@billgatliff.com> wrote:
> > At least until someone plugs in that expansion module!
> >
> Bill's remark made a neuron connection in my head:
> 
> Can you detect if the module is inserted or not? (By reading a known
> state of some pin)?

I can, although it's a bit more complex than that. The module is connected to the main board I2C bus so I can detect its presence by checking if chips connected to the bus are detected. Using a GPIO would have been much easier, but that's life :-)

> You could then configure the pins dynamically in your driver.

That's what I'm doing. As dynamic pin configuration requires board-specific knowledge in the device driver I would have liked to avoid that if possible.

Best regards, and thanks for your help.

-- 
Laurent Pinchart
CSE Semaphore Belgium

Chaussee de Bruxelles, 732A
B-1410 Waterloo
Belgium

T +32 (2) 387 42 59
F +32 (2) 387 42 75

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