Re: [PATCH] hwmon: (max6650) Add support for gpiodef

[Laszlo Papp]

On Thu, Nov 14, 2013 at 7:00 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> What are those pins used for ?

I would like to drive them dynamically like the rest of the features
exposed to the sysfs in a similar way.

For instance, one may need to output a logic-low level on the pin 0 to
get an operation working. One use case could be (and is) enabling or
disabling the fans dynamically based on the temperature, etc
condition. Imagine that if you have a 12 V fan with 5 V board power
supply, and such a pin would be useful to establish the bridge between
them with diodes.

This is just one use case of those, you could also use it for
non-generic gpio functionality, like alarm, "full-on", internal clock,
external clock, etc. I believe it is always a bit tricky with MFD. I
personally prefer to put it into the chip driver because this is not
clearly a generic gpio interface here, and I need to drive it
dynamically.
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