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From: Charles Keepax <ckeepax@opensource.cirrus.com>
To: Matthias Reichl <hias@horus.com>, <broonie@kernel.org>,
	<lgirdwood@gmail.com>, <linus.walleij@linaro.org>,
	<patches@opensource.cirrus.com>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] regulator: arizona-ldo1: Use correct device to get enable GPIO
Date: Tue, 19 Jun 2018 15:07:30 +0100	[thread overview]
Message-ID: <20180619140730.GG18740@imbe.wolfsonmicro.main> (raw)
In-Reply-To: <20180619122432.6rgh4zjqrfk45ofs@camel2.lan>

On Tue, Jun 19, 2018 at 02:24:33PM +0200, Matthias Reichl wrote:
> On Tue, Jun 19, 2018 at 10:32:45AM +0100, Charles Keepax wrote:
> > +	config.ena_gpiod = gpiod_get_optional(parent_dev, "wlf,ldoena",
> > +					      GPIOD_OUT_HIGH);
> 
> The WM5102 datasheet lists LDOENA as an active-high input,
> so GPIOD_OUT_HIGH causes arizona-ldo1 to start up enabled.
> Not sure about the other devices from the Arizona family.
> 

Yeah all active high.

> I did some tests monitoring ldoena and reset gpios with my scope:
> 
> With commit e1739e86f0cb reverted ldoena changes from low to high
> about 1.6ms before reset changes from low to high.
> 
> With your patch ldoena goes high about 11.5ms before reset goes high.
> 
> With your patch and GPIOD_OUT_HIGH changed to GPIOD_OUT_LOW
> the delay is again about 1.6ms.
> 
> So I guess it'd be better to adjust the comment and change
> to gpiod flag to GPIOD_OUT_LOW.

Yeah I am inclined to agree would be better to keep the behaviour
the same as it has always been given these parts are fairly
mature I will respin the patch to add that change too.

Thanks,
Charles

      reply	other threads:[~2018-06-19 14:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-19  9:32 [PATCH] regulator: arizona-ldo1: Use correct device to get enable GPIO Charles Keepax
2018-06-19 12:24 ` Matthias Reichl
2018-06-19 14:07   ` Charles Keepax [this message]

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