linux-kernel - Re: [PATCH] rtc: pcf8563: disable CLKOUT

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Message-ID: <20151013201703.GA3421@piout.net>
Date:	Tue, 13 Oct 2015 22:17:03 +0200
From:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:	Heiko Schocher <hs@...x.de>
Cc:	linux-kernel@...r.kernel.org, Georg.Soffel@...ch-si.com,
	rtc-linux@...glegroups.com,
	Alessandro Zummo <a.zummo@...ertech.it>,
	devicetree@...r.kernel.org
Subject: Re: [PATCH] rtc: pcf8563: disable CLKOUT

Hi,

On 13/10/2015 at 07:08:58 +0200, Heiko Schocher wrote :
> Disable the CLKOUT of the RTC after power-up.
> After power-up/reset of the RTC, CLKOUT is enabled by default,
> with CLKOUT enabled the RTC chip has 2-3 times higher power
> consumption. If you do not need CLKOUT, you can disable the
> CLKOUT with setting "disable-clkout" property.
> 

I think you can simply unconditionally disable clkout. My preferred way
of doing what you suggest is probably to register a clock in the CCF. If
the clock is not used, it will be automatically disabled.
It will also provide a generic way of setting the clkout frequency (some
RTC are able to output 32kHZ, 1kHz and 1Hz).

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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