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GPIO: Handling multiple lines at once

DISCUSSION Roland Stigge 2 participants 2 messages Jan 18, 2011 – Jan 19, 2011

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#0 lore raw

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

#1 lore raw
Quoted 5 lines · Roland Stigge

Hi,

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

Quoted 8 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.

Quoted 4 lines

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.
Quoted 11 lines

Please CC me.

Thanks in advance!

Roland
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