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From: Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Maxime Ripard
	<maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
Cc: Alessandro Zummo
	<a.zummo-BfzFCNDTiLLj+vYz1yj4TQ@public.gmane.org>,
	Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 0/6] rtc: sun6i: Fix the RTC accuracy
Date: Sun, 22 Jan 2017 15:32:44 +0100	[thread overview]
Message-ID: <20170122143244.n2d4fpxnt62tkwtt@piout.net> (raw)
In-Reply-To: <cover.180d5ae6bc36ead9625d208824f5cbd7114cf92e.1484927680.git-series.maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>

On 20/01/2017 at 16:56:37 +0100, Maxime Ripard wrote :
> Hi,
> 
> The RTC used in the A31 and later SoC has an accuracy issue, which is
> already significant even after a couple of hours.
> 
> This is due to the fact that the oscillator used by default is an internal
> and very inaccurate one.
> 
> A first attempt at fixing that by switching to the external oscillator was
> done in the patch "rtc: sun6i: Switch to the external oscillator". However,
> it turned out to be problematic since it was tracked properly in the clock
> framework, which might lead to some clocks being disabled, even though
> their devices were not notified.
> 
> This is a second attempt, this time by making it part of the CCF. It
> turned out to be a bit more complicated than one would expect since the mux
> found inside the RTC also controls one of the input of the main clock unit.
> Therefore, it needs to be probed before the main clock unit driver.
> 
> Let me know what you think,
> Maxime
> 
> Maxime Ripard (6):
>   rtc: sun6i: Expose the 32kHz oscillator
>   rtc: sun6i: Add some locking
>   rtc: sun6i: Disable the build as a module
>   rtc: sun6i: Force the mux to the external oscillator
>   ARM: sun8i: a23/a33: Enable the real LOSC and use it
>   ARM: sun8i: a23/a33: Add the oscillators accuracy
> 

As Chen-Yu mentioned, maybe you can reorder some patches so they can go
in stable.

>  Documentation/devicetree/bindings/rtc/sun6i-rtc.txt |   8 +-
>  arch/arm/boot/dts/sun8i-a23-a33.dtsi                |  15 +-
>  drivers/rtc/Kconfig                                 |   2 +-
>  drivers/rtc/rtc-sun6i.c                             | 189 +++++++++++--
>  4 files changed, 181 insertions(+), 33 deletions(-)
> 
> base-commit: 99cef370ac9939df2aeb16c96d07e842b2fa8201
> -- 
> git-series 0.8.11

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

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      parent reply	other threads:[~2017-01-22 14:32 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-20 15:56 [PATCH 0/6] rtc: sun6i: Fix the RTC accuracy Maxime Ripard
     [not found] ` <cover.180d5ae6bc36ead9625d208824f5cbd7114cf92e.1484927680.git-series.maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2017-01-20 15:56   ` [PATCH 1/6] rtc: sun6i: Expose the 32kHz oscillator Maxime Ripard
     [not found]     ` <f1b2a5053cf143dccf110ab0d40c082903a958a7.1484927680.git-series.maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2017-01-21  2:14       ` Chen-Yu Tsai
2017-01-22 14:17       ` Alexandre Belloni
2017-01-20 15:56   ` [PATCH 2/6] rtc: sun6i: Add some locking Maxime Ripard
     [not found]     ` <9b5c8ed82f636fd2061a9b7933c0e6b65d868643.1484927680.git-series.maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2017-01-21  2:18       ` Chen-Yu Tsai
2017-01-20 15:56   ` [PATCH 3/6] rtc: sun6i: Disable the build as a module Maxime Ripard
     [not found]     ` <de1e4b4eda6307b664c40d6c4502058f6bb88c60.1484927680.git-series.maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2017-01-21  2:32       ` Chen-Yu Tsai
2017-01-20 15:56   ` [PATCH 4/6] rtc: sun6i: Force the mux to the external oscillator Maxime Ripard
     [not found]     ` <409c56f0ed1c4b0026ad60cb1218c99fe1686408.1484927680.git-series.maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2017-01-21  3:53       ` Chen-Yu Tsai
     [not found]         ` <CAGb2v650f-4RZ6RrRBGcmPz8mJ4KbJwTTj6=w3HeSWUZtLAKcw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-01-22 14:44           ` Alexandre Belloni
2017-01-20 15:56   ` [PATCH 5/6] ARM: sun8i: a23/a33: Enable the real LOSC and use it Maxime Ripard
2017-01-20 15:56   ` [PATCH 6/6] ARM: sun8i: a23/a33: Add the oscillators accuracy Maxime Ripard
2017-01-22 14:32   ` Alexandre Belloni [this message]

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