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From: "Uwe Kleine-König" <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
To: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>,
	Wim Van Sebroeck <wim-IQzOog9fTRqzQB+pC5nmwQ@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Alexander Shiyan <shc_work-JGs/UdohzUI@public.gmane.org>,
	Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>,
	Ian Campbell
	<ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>,
	Mike Looijmans <mike.looijmans-Oq418RWZeHk@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
	Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Subject: Re: [RFC] improve binding for linux,wdt-gpio
Date: Thu, 30 Jul 2015 23:30:39 +0200	[thread overview]
Message-ID: <20150730213039.GR15360@pengutronix.de> (raw)
In-Reply-To: <1438115628-2819-1-git-send-email-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

Hello,

while hacking on the gpio driver I found yet another ambiguity:

On Tue, Jul 28, 2015 at 10:33:48PM +0200, Uwe Kleine-König wrote:
> -  - level: Low or high level starts counting WDT timeout,
> -    the opposite level disables the WDT. Active level is determined
> -    by the GPIO flags.
The driver as is does the following when

	gpio = <&gpiocontroler 5 GPIO_ACTIVE_LOW>

is specified in the device tree:

	priv->active_low = flags & OF_GPIO_ACTIVE_LOW;

So active_low is 1 for us with the above device tree snippet.

Then in the disable callback the driver does:

	gpio_set_value_cansleep(priv->gpio, !priv->active_low);

so the gpio is set to 0 to disable the chip. I would have expected it
the other way round! (Is this only me?) So the documentation should
point that out that the active level of the GPIO is supposed to disable the
chip.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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      parent reply	other threads:[~2015-07-30 21:30 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-28 20:33 [RFC] improve binding for linux,wdt-gpio Uwe Kleine-König
     [not found] ` <1438115628-2819-1-git-send-email-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2015-07-28 21:21   ` Guenter Roeck
     [not found]     ` <20150728212155.GA18137-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2015-07-29  7:35       ` Uwe Kleine-König
     [not found]         ` <20150729073513.GB15360-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2015-07-29 15:49           ` Guenter Roeck
     [not found]             ` <55B8F603.4000003-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2015-07-30  6:59               ` Uwe Kleine-König
     [not found]                 ` <20150730065951.GI15360-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2015-07-30  7:25                   ` Guenter Roeck
     [not found]                     ` <55B9D153.5080202-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2015-07-30  7:33                       ` Uwe Kleine-König
2015-07-30  6:15           ` Mike Looijmans
     [not found]             ` <55B9C102.50608-Oq418RWZeHk@public.gmane.org>
2015-07-30  7:25               ` Uwe Kleine-König
2015-07-30 21:30   ` Uwe Kleine-König [this message]

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