linux-kernel - Re: [RFC PATCH 1/4] dt-binding: i2c: add generic properties for GPIO bus recovery

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Message-ID: <20200724205209.GC1551@shell.armlinux.org.uk>
Date:   Fri, 24 Jul 2020 21:52:09 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Wolfram Sang <wsa@...nel.org>
Cc:     Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>,
        linux-i2c@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        robh+dt@...nel.org, ludovic.desroches@...rochip.com,
        nicolas.ferre@...rochip.com, alexandre.belloni@...tlin.com,
        kamel.bouhara@...tlin.com
Subject: Re: [RFC PATCH 1/4] dt-binding: i2c: add generic properties for GPIO
 bus recovery

On Fri, Jul 24, 2020 at 09:39:13PM +0200, Wolfram Sang wrote:
> On Sun, Jul 05, 2020 at 11:19:18PM +0200, Wolfram Sang wrote:
> > 
> > > +- pinctrl
> > > +	add extra pinctrl to configure SCL/SDA pins to GPIO function for bus
> > > +	recovery, call it "gpio" or "recovery" state
> > 
> > I think we should stick with "gpio" only. That is what at91 and imx have
> > in their bindings. pxa uses "recovery" as a pinctrl state name but I
> > can't find any further use or documentation of that. PXA is not fully
> > converted to the best of my knowledge, so maybe it is no problem for PXA
> > to switch to "gpio", too? We should ask Russell King (cced).

Fully converted to what?  The generic handling where the i2c core layer
handles everything to do with recovery, including the switch between
modes?

i2c-pxa _intentionally_ carefully handles the switch between i2c mode and
GPIO mode, and I don't see a generic driver doing that to avoid causing
any additional glitches on the bus.  Given the use case that this recovery
is targetted at, avoiding glitches is very important to keep.

> > Russell, do you object naming the pinctrl state for bus recovery in
> > the pxa i2c driver from "recovery" to "gpio"?
> 
> No response, so far. I suggest now to support the "recovery" naming but
> mark it as deprecated. Opinions?

I don't have a preference on the exact naming.

-- 
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