From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751763Ab2DYGoa (ORCPT ); Wed, 25 Apr 2012 02:44:30 -0400 Received: from mail.karo-electronics.de ([81.173.242.67]:62210 "EHLO mail.karo-electronics.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750821Ab2DYGo2 (ORCPT ); Wed, 25 Apr 2012 02:44:28 -0400 Message-ID: <20375.40225.227084.644318@ipc1.ka-ro> Date: Wed, 25 Apr 2012 08:43:45 +0200 From: =?utf-8?Q?Lothar_Wa=C3=9Fmann?= To: Andrew Lunn Cc: viresh kumar , Russell King - ARM Linux , sshtylyov@mvista.com, spear-devel@list.st.com, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, mturquette@linaro.org, akpm@linux-foundation.org, jgarzik@redhat.com, linux-arm-kernel@lists.infradead.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH V3 07/12] ata/sata_mv: Remove conditional compilation of clk code In-Reply-To: <20120425052802.GF13489@lunn.ch> References: <20120424120019.GE24089@lunn.ch> <20120424201802.GE3628@n2100.arm.linux.org.uk> <20120425052802.GF13489@lunn.ch> X-Mailer: VM 8.1.0 under 23.2.1 (i486-pc-linux-gnu) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Andrew Lunn writes: > > This is what i was thinking too and thats why floated this version of patch. > > But as Andrew said, clk API support is enabled for them, but still they > > don't have a clk for sata. To get this working, there are two solutions: > > - Create dummy clk for sata for that platform, so clk_get doesn't fail. > > - Check for error before every call to clk APIs after clk_get(). > > > > Andrew favored the second one. Which means, even on platforms > > with clk API defined and clk enable required, if there are some issues > > with lookup table, and clk_get() fails, system may hang when registers > > are accessed. For this i favored first one. > > I'm not too sure how you are going to achieve 1) > > config SATA_MV > tristate "Marvell SATA support" > help > This option enables support for the Marvell Serial ATA family. > Currently supports 88SX[56]0[48][01] PCI(-X) chips, > as well as the newer [67]042 PCI-X/PCIe and SOC devices. > > So this driver can be used with anything which has a PCI(-X) or PCIe > bus, or Orion SoC and a few PowerPC SoCs. > > The SoCs are not too bad, we know which ones they are and we can add > dummy entries to their device tree. However, how do you want to handle > the PCI devices? Create the dummy entry somewhere in the middle of the > PCI core? > > Thought not. > AFAICT the PCI archs do not have HAVE_CLK enabled. Thus they will have a dummy clk API in place that provides the driver with a non-error clk_get() return value. Lothar Waßmann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Geschäftsführer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info@karo-electronics.de ___________________________________________________________