From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751996AbdHGVmH (ORCPT ); Mon, 7 Aug 2017 17:42:07 -0400 Received: from mail-pg0-f54.google.com ([74.125.83.54]:37937 "EHLO mail-pg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751834AbdHGVmF (ORCPT ); Mon, 7 Aug 2017 17:42:05 -0400 From: Kevin Hilman To: Jerome Brunet Cc: Ulf Hansson , Carlo Caione , linux-mmc@vger.kernel.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 13/14] mmc: meson-gx: work around clk-stop issue Organization: BayLibre References: <20170804174353.16486-1-jbrunet@baylibre.com> <20170804174353.16486-14-jbrunet@baylibre.com> Date: Mon, 07 Aug 2017 14:41:57 -0700 In-Reply-To: <20170804174353.16486-14-jbrunet@baylibre.com> (Jerome Brunet's message of "Fri, 4 Aug 2017 19:43:52 +0200") Message-ID: <7hzibbnjh6.fsf@baylibre.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jerome Brunet writes: > It seems that the signal clock is also used and required, somehow, by > the controller it self. > > It is shown during init, when writing to CFG while the divider is set > to 0 will crash the SoC. During voltage switch, the controller may crash > and the card may then fail to exit busy state if the clock is stopped. > > To avoid this, it is best to keep the clock running for the controller, > except during rate change. However, we still need to be able to gate > the clock out of the SoC. Let's use the pinmux for this, and fallback > to gpio mode (pulled-down) when we need to gate the clock > > Signed-off-by: Jerome Brunet Curious "feature" of the IP, but the solution looks good to me. Reviewed-by: Kevin Hilman Kevin