Re: register access issues in pca953x gpio driver

[Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>]

Hello Mark,

On Fri, Mar 27, 2020 at 01:03:21PM +0000, Mark Brown wrote:
> On Fri, Mar 27, 2020 at 08:49:22AM +0100, Uwe Kleine-König wrote:
> 
> > @broonie: I don't know regmap good enough to instantly know the right
> > magic to do this. Can you give a rough overview what would be needed?
> 
> If you want to dynamically change if the register is autoincrementing
> you're going to have to add stuff to regmap for that, it understands
> devices that autoincrement and devices that don't autoincrement but
> there's currently nothing for transitioning between the two.

I'm not entirely sure, but I think they all support autoincrementing but
some need the flag set and others don't. I imagine that this should be
modeled as register range [0-0x7f] (as AI = 0x80) and the accessor
callbacks have to set AI or not depending on the chip.

Best regards
Uwe

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