Re: [PATCH 1/2] dt-bindings: gpio: introduce hog properties with less ambiguity

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

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Hello,

On Tue, May 04, 2021 at 06:24:54PM +0800, Kent Gibson wrote:
> On Tue, May 04, 2021 at 11:14:59AM +0200, Uwe Kleine-König wrote:
> > On Tue, May 04, 2021 at 10:55:46AM +0800, Kent Gibson wrote:
> > > On Mon, May 03, 2021 at 11:05:26PM +0200, Uwe Kleine-König wrote:
> > > > For active low lines the semantic of output-low and output-high is hard
> > > > to grasp because there is a double negation involved and so output-low
> > > > is actually a request to drive the line high (aka inactive).
> > > 
> > > +1 on clarifying the naming.
> > > 
> > > > So introduce output-inactive and output-active with the same semantic as
> > > > output-low and output-high respectively have today, but with a more
> > > > sensible name.
> > > > 
> > > 
> > > You use active/inactive here, but then asserted/deasserted in the patch.
> > 
> > oops, this is an oversight.
> > 
> > > My preference would be the active/inactive, which has more of a level
> > > feel, over the asserted/deasserted which feels more like an edge.
> > > 
> > > And you still use active/inactive in the descriptions, so now we have all
> > > three naming schemes in the mix.  
> > > 
> > > What made you change?
> > 
> > I had active/inactive first, but Linux Walleij requested
> > asserted/deasserted:
> > 
> > https://lore.kernel.org/r/CACRpkdbccHbhYcCyPiSoA7+zGXBtbL_LwLkPB3vQDyOqkTA7EQ@mail.gmail.com
> 
> Thanks - I'd missed that.
> 
> I don't suppose you happen to have a link to the gpiod_set_value()
> discussion that Linus mentions?

I found https://lore.kernel.org/linux-gpio/CACRpkdZAm5AML6cfrX_VrzyADASj1rsVXC3zwtfdo+aRSgX7fQ@mail.gmail.com/
but not that other thread Linus mentions there. I would have expected
https://lore.kernel.org/linux-gpio/?q=GPIO_OUT_ASSERTED to find it, but
it doesn't.

> > While I like active/inactive better than asserted/deasserted, the latter
> > is still way better than high/low, so I didn't discuss.
> > 
> 
> As a native English speaker, I find deasserted to be awkward - though it
> is the appropriate negative of asserted in this context.
> 
> And there is no escaping the naming of the active-low, so I'm curious to

Ack, we shouldn't rename that to assert-low :-)

> know if there is a good reason not to go with active/inactive.

Linus: So we're already 3 out of 3 who would like active/inactive better
than asserted/deasserted. I'm curious about your preference, too.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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