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From: Tony Lindgren <tony@atomide.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Alexandre Courbot <gnurou@gmail.com>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Kevin Hilman <khilman@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	linux-gpio@vger.kernel.org, kernel@pengutronix.de,
	Santosh Shilimkar <ssantosh@kernel.org>,
	linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2 v2] gpio: omap: make gpio numbering deterministical by using of aliases
Date: Tue, 21 Jun 2016 04:28:59 -0700	[thread overview]
Message-ID: <20160621112858.GO22406@atomide.com> (raw)
In-Reply-To: <1465930632-18941-2-git-send-email-u.kleine-koenig@pengutronix.de>

* Uwe Kleine-König <u.kleine-koenig@pengutronix.de> [160614 12:03]:
> Traditionally the n-th gpio device probed by the omap gpio driver got
> the gpio number range [n*32 .. n*32+31].
> When order of the devices probed by the driver changes (which can happen
> already now when some devices have a pinctrl and so the first probe
> attempt returns -ENODEV) the numbering changes.
> 
> To ensure a deterministical numbering use of_alias_get_id to determine
> the base for a given device. If no respective alias exists fall back to
> the traditional numbering.
> 
> For the unusual case where only a part of the gpio devices have a
> matching alias some of them might fail to probe. But if none of them has
> an alias or all, there is no conflict which should be good enough to
> maintain backward compatibility.

I think doing this is a good idea to prevent nasty suprises when
upgrading a kernel on some device:

Acked-by: Tony Lindgren <tony@atomide.com>

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linux-arm-kernel@lists.infradead.org
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WARNING: multiple messages have this Message-ID (diff)
From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2 v2] gpio: omap: make gpio numbering deterministical by using of aliases
Date: Tue, 21 Jun 2016 04:28:59 -0700	[thread overview]
Message-ID: <20160621112858.GO22406@atomide.com> (raw)
In-Reply-To: <1465930632-18941-2-git-send-email-u.kleine-koenig@pengutronix.de>

* Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de> [160614 12:03]:
> Traditionally the n-th gpio device probed by the omap gpio driver got
> the gpio number range [n*32 .. n*32+31].
> When order of the devices probed by the driver changes (which can happen
> already now when some devices have a pinctrl and so the first probe
> attempt returns -ENODEV) the numbering changes.
> 
> To ensure a deterministical numbering use of_alias_get_id to determine
> the base for a given device. If no respective alias exists fall back to
> the traditional numbering.
> 
> For the unusual case where only a part of the gpio devices have a
> matching alias some of them might fail to probe. But if none of them has
> an alias or all, there is no conflict which should be good enough to
> maintain backward compatibility.

I think doing this is a good idea to prevent nasty suprises when
upgrading a kernel on some device:

Acked-by: Tony Lindgren <tony@atomide.com>

  reply	other threads:[~2016-06-21 11:28 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-14 18:57 [PATCH 0/2 v2] gpio-omap: ensure a stable gpio numbering Uwe Kleine-König
2016-06-14 18:57 ` Uwe Kleine-König
2016-06-14 18:57 ` [PATCH 1/2 v2] gpio: omap: make gpio numbering deterministical by using of aliases Uwe Kleine-König
2016-06-14 18:57   ` Uwe Kleine-König
2016-06-21 11:28   ` Tony Lindgren [this message]
2016-06-21 11:28     ` Tony Lindgren
2016-06-21 17:01   ` Grygorii Strashko
2016-06-21 17:01     ` Grygorii Strashko
2016-06-23  8:54   ` Linus Walleij
2016-06-23  8:54     ` Linus Walleij
2016-06-14 18:57 ` [PATCH 2/2 v2] ARM: dts: add aliases for ti,omap[234]-gpio devices Uwe Kleine-König
2016-06-14 18:57   ` Uwe Kleine-König

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