Re: [PATCH 3/4] dt-bindings: gpio: max3191x: Document new driver

[Lukas Wunner <lukas@wunner.de>]

Hi Rob,

gentle ping on this question:

On Tue, Sep 05, 2017 at 10:16:24AM +0200, Lukas Wunner wrote:
> Hi Rob,
> 
> sorry to bother you again, one more question popped up regarding the
> MAX3191x DT bindings:
> 
> On Tue, Aug 22, 2017 at 07:48:47PM -0500, Rob Herring wrote:
> > On Mon, Aug 21, 2017 at 03:12:00PM +0200, Lukas Wunner wrote:
> > > Add device tree bindings for Maxim MAX3191x industrial serializer.
> [snip]
> > > +Optional properties:
> > > + - maxim,nchips:	Number of chips in the daisy-chain (default is 1).
> 
> Many I/O chips are daisy-chainable, so I've been wondering if a
> common property should be introduced?
> 
> The existing gpio-74x164.c uses "registers-number" to convey the number
> of chips in the daisy chain.  (Sans vendor prefix, multiple vendors sell
> compatible versions of this chip.)
> 
> gpio-pisosr.c takes a different approach and calculates the number of
> chips in the daisy-chain by taking the common "ngpios" property
> (Documentation/devicetree/bindings/gpio/gpio.txt) and dividing it by 8
> (which assumes that each chip has 8 inputs).
> 
> Thanks,
> 
> Lukas