From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Stuebner Subject: Re: [PATCH 3/4] phy: rockchip-emmc: configure default output tap delay Date: Fri, 17 Jun 2016 01:36:45 +0200 Message-ID: <1614232.pce5aJ6WZ3@phil> References: <1463092986-61777-1-git-send-email-briannorris@chromium.org> <1463092986-61777-3-git-send-email-briannorris@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <1463092986-61777-3-git-send-email-briannorris@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: Brian Norris Cc: Kishon Vijay Abraham I , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, Doug Anderson , Shawn Lin , linux-arm-kernel@lists.infradead.org, Brian Norris List-Id: linux-rockchip.vger.kernel.org Am Donnerstag, 12. Mai 2016, 15:43:05 schrieb Brian Norris: > The output tap delay controls helps maintain the hold requirements for > eMMC. The exact value is dependent on the SoC and other factors, though > it isn't really an exact science. But the default of 0 is not very good, > as it doesn't give the eMMC much hold time, so let's bump up to 4 > (approx 90 degree phase?). If we need to configure this any further > (e.g., based on board or speed factors), we may need to consider a > device tree representation. > > Suggested-by: Shawn Lin > Signed-off-by: Brian Norris on my rk3399-evb board the emmc still runs nicely with this patch, so Tested-by: Heiko Stuebner