Re: [PATCH v3 18/27] mtd: nand: omap2: Implement NAND ready using gpiolib

From: Boris Brezillon
Date: Tue Oct 27 2015 - 04:12:48 EST

Hi Roger,

On Tue, 27 Oct 2015 10:03:02 +0200
Roger Quadros <rogerq@xxxxxx> wrote:

> On 26/10/15 22:49, Brian Norris wrote:
> >
> > Others have been looking at using GPIOs for the ready/busy pin too. At a
> > minimum, we need an updated DT binding doc for this, since I see you're
> > adding this via device tree in a later patch (I don't see any DT binding
> > patch for this; but I could just be overlooking it). It'd also be great
> > if this support was moved to nand_dt_init() so other platforms can
> > benefit, but I won't require that.
> >
> > Also, previous [0] proposers had suggested 'rb-gpios', not 'ready-gpio'
> > (the hardware docs typically call it 'rb' for ready/busy, FWIW). I don't
> > really care, but the name should be going into a doc, so we can choose
> > the same one everywhere.
> >
> > EDIT: looks like the discussion was partly here [1] and it seems we're
> > landing on "rb-gpios" in the latest version [2]. Can we stick with that?
> Why should it be "rb-gpios" and not "rb-gpio"?
> I don't think there are multiple gpios for r/b# function.

Because it's supposed to be a generic binding, and some NAND chips
embed several dies, thus exposing several CS and RB pins, hence the
rb-gpios name.
Also, as described here [1], the convention is to name your property
<name>-gpios even if you only need one gpio.

Best Regards,



Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
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