GPIO: Handling multiple lines at once

GPIO: Handling multiple lines at once

[Roland Stigge]

Hi,

in the standard gpio interface (see Documentation/gpio.txt), we have an
interface to manipulate single GPIO lines.

Several drivers are implementing an interface for devices that can
handle multiple lines at once. E.g. Maxim MAX7301
(drivers/gpio/max7301.c). There, you can get/set/configure 8 bits at
once which is really helpful if you are handling 8 bit data as
bytes/characters via the lines.

Is there an appropriate interface for this case that I'm somehow missing
from the docs and the code?

Or do I need to create it myself?

Or is this a use case not considered "GPIO" at all?

Please CC me.

Thanks in advance!

Roland

Re: GPIO: Handling multiple lines at once

[Ben Nizette]

On 19/01/2011, at 3:15 AM, Roland Stigge wrote:

> Hi,
> 
> in the standard gpio interface (see Documentation/gpio.txt), we have an
> interface to manipulate single GPIO lines.
> 
> Several drivers are implementing an interface for devices that can
> handle multiple lines at once. E.g. Maxim MAX7301
> (drivers/gpio/max7301.c). There, you can get/set/configure 8 bits at
> once which is really helpful if you are handling 8 bit data as
> bytes/characters via the lines.
> 
> Is there an appropriate interface for this case that I'm somehow missing
> from the docs and the code?

Such code isn't upstream, no.

> 
> Or do I need to create it myself?
> 
> Or is this a use case not considered "GPIO" at all?

It's a use case considered less useful than the single-pin case and much much harder to get right.  Search the archives for examples of previous attempts to add this functionality and their failings, if you feel you can correct them please give it a shot!

	--Ben.

> 
> Please CC me.
> 
> Thanks in advance!
> 
> Roland
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