From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753884AbbG0QYX (ORCPT ); Mon, 27 Jul 2015 12:24:23 -0400 Received: from mail-wi0-f169.google.com ([209.85.212.169]:38857 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753275AbbG0QYT (ORCPT ); Mon, 27 Jul 2015 12:24:19 -0400 Date: Mon, 27 Jul 2015 17:24:13 +0100 From: Lee Jones To: Mika Westerberg Cc: Andy Shevchenko , linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, Greg Kroah-Hartman , Vinod Koul , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Heikki Krogerus , Jarkko Nikula , "Wysocki, Rafael J" , mturquette@baylibre.com, sboyd@codeaurora.org Subject: Re: [PATCH v6 0/8] mfd: introduce a driver for LPSS devices on SPT Message-ID: <20150727162413.GE21114@x1> References: <1438009443-55317-1-git-send-email-andriy.shevchenko@linux.intel.com> <20150727152733.GB21114@x1> <20150727160447.GL1577@lahna.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150727160447.GL1577@lahna.fi.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 27 Jul 2015, Mika Westerberg wrote: > On Mon, Jul 27, 2015 at 04:27:33PM +0100, Lee Jones wrote: > > FAO Stephen Boyd, > > > > > Stephen, can you, please, have a look into patch 8 regarding to clock name > > > matching and other stuff Lee asked? > > > > Patch 8: > > > > "Can you review the clock implementation please? It looks > > fragile to me as it relies heavily on device names constructed > > of MFD cell names and IDA numbers cat'ed together!" > > Lee, can you suggest an alternative then? > > Why we are doing it like this is that number of different LPSS devices > changes from SoC to SoC. In addition to that the device (called "slice") > might have iDMA block or not. > > Since the drivers in question (pxa2xx-spi, i2c-designware and 8250_dw) > use standard clk framework to request their clocks the Linux device must > have clock registered which matches the device in advance. > > Because we add the host controller device dynamically (from the MFD > driver) based on how many devices are actually present, we need somehow > predict what would be the correct name and instance number for that > device to get the clock for it. That's the reason we use IDA here along > with the cell name (or driver name). I'm sure there are perfectly viable reasons for you doing this. And I don't know the CCF well enough to know whether it's the best idea or not, or else I would have made a suggestion rather than waiting all this time. It's for this reason that I needed Mike (now Stephen) to take a look and give me either an Ack, to say it's the best solution, or to provide a better alternative. Until that happens, I'm stuck! -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog