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Message-ID: <20170721072039.qsko2vtradiosdqk@flea>
Date: Fri, 21 Jul 2017 09:20:39 +0200
From: Maxime Ripard <maxime.ripard@...e-electrons.com>
To: Chen-Yu Tsai <wens@...e.org>
Cc: Ulf Hansson <ulf.hansson@...aro.org>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...eaurora.org>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
linux-arm-kernel@...ts.infradead.org, linux-mmc@...r.kernel.org,
linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v2 04/10] mmc: sunxi: Support controllers that can use
both old and new timings
On Thu, Jul 20, 2017 at 11:44:46AM +0800, Chen-Yu Tsai wrote:
> On the SoCs that introduced the new timing mode for MMC controllers,
> both the old (where the clock delays are set in the CCU) and new
> (where the clock delays are set in the MMC controller) timing modes
> are available, and we have to support them both. However there are
> two bits that control which mode is active. One is in the CCU, the
> other is in the MMC controller. The settings on both sides must be
> the same, or nothing will work.
>
> The sunxi-ng clock driver provides an API to query and set the
> active timing mode. At probe time, we try to set the active mode
> to the "new timing mode". If it succeeds, we can then use the MMC
> controller in the new mode. If not, we fall back to the old mode.
>
> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
Acked-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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