From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v2 04/10] mmc: sunxi: Support controllers that can use both old and new timings Date: Fri, 21 Jul 2017 09:20:39 +0200 Message-ID: <20170721072039.qsko2vtradiosdqk@flea> References: <20170720034452.15920-1-wens@csie.org> <20170720034452.15920-5-wens@csie.org> Reply-To: maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="5aoxigudzrnhotcx" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Content-Disposition: inline In-Reply-To: <20170720034452.15920-5-wens-jdAy2FN1RRM@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Chen-Yu Tsai Cc: Ulf Hansson , Michael Turquette , Stephen Boyd , Rob Herring , Mark Rutland , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Id: devicetree@vger.kernel.org --5aoxigudzrnhotcx Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline 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 Acked-by: Maxime Ripard Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --5aoxigudzrnhotcx--