From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754877AbbG1Hqc (ORCPT ); Tue, 28 Jul 2015 03:46:32 -0400 Received: from mail-wi0-f181.google.com ([209.85.212.181]:34425 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750844AbbG1Hqa (ORCPT ); Tue, 28 Jul 2015 03:46:30 -0400 Date: Tue, 28 Jul 2015 08:46:25 +0100 From: Lee Jones To: "Rafael J. Wysocki" Cc: Mika Westerberg , 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: <20150728074625.GN21114@x1> References: <1438009443-55317-1-git-send-email-andriy.shevchenko@linux.intel.com> <20150727212748.GF21114@x1> <20150727212934.GH21114@x1> <2258476.9C4JjWNs6u@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2258476.9C4JjWNs6u@vostro.rjw.lan> 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 Tue, 28 Jul 2015, Rafael J. Wysocki wrote: > On Monday, July 27, 2015 10:29:34 PM Lee Jones wrote: > > On Mon, 27 Jul 2015, Lee Jones wrote: > > > > > On Mon, 27 Jul 2015, Rafael J. Wysocki wrote: > > > > > > > On Monday, July 27, 2015 05:24:13 PM Lee Jones wrote: > > > > > 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! > > > > > > > > Well, what if we had no one at hand to review that code? Would that mean it > > > > would not be applicable forever? > > > > > > No, but that's not the case is it? > > > > > > I don't understand why Mike and Stephen aren't helping! > > > > I'll wait until tomorrow and if we haven't heard anything I'll make a > > decision. > > OK, thanks! > > BTW, I don't have the time to review every single patch using ACPI > or one of the PM frameworks. If people who use them make mistakes, > it is their burden to fix those mistakes when they show up in testing. > > What's happening here is that Andy and Mika are taking the responsibility > for fixing the new code if it turns out to be buggy and so it's their > problem if it happens to be broken. > > And you can still revert commits that introduce bugs as a last resort. I'm fine with that in principle. My issue here was that it looks wrong to me. I just don't know enough about the inner workings of the CCF to be able to say that for sure, or to provide a suitable alternative. I think, probably the correct thing to do is to have an accompanying clock driver, but who knows (I guess Stephen and Mike to, but are seemingly unwilling to help). -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog