From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v6 0/8] mfd: introduce a driver for LPSS devices on SPT Date: Tue, 28 Jul 2015 08:46:25 +0100 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-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <2258476.9C4JjWNs6u@vostro.rjw.lan> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-pm@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: > >=20 > > > On Mon, 27 Jul 2015, Rafael J. Wysocki wrote: > > >=20 > > > > On Monday, July 27, 2015 05:24:13 PM Lee Jones wrote: > > > > > On Mon, 27 Jul 2015, Mika Westerberg wrote: > > > > >=20 > > > > > > On Mon, Jul 27, 2015 at 04:27:33PM +0100, Lee Jones wrote: > > > > > > > FAO Stephen Boyd, > > > > > > >=20 > > > > > > > > Stephen, can you, please, have a look into patch 8 rega= rding to clock name > > > > > > > > matching and other stuff Lee asked? > > > > > > >=20 > > > > > > > Patch 8: > > > > > > >=20 > > > > > > > "Can you review the clock implementation please? I= t looks > > > > > > > fragile to me as it relies heavily on device names = constructed > > > > > > > of MFD cell names and IDA numbers cat'ed together!" > > > > > >=20 > > > > > > Lee, can you suggest an alternative then? > > > > > >=20 > > > > > > Why we are doing it like this is that number of different L= PSS devices > > > > > > changes from SoC to SoC. In addition to that the device (ca= lled "slice") > > > > > > might have iDMA block or not. > > > > > >=20 > > > > > > Since the drivers in question (pxa2xx-spi, i2c-designware a= nd 8250_dw) > > > > > > use standard clk framework to request their clocks the Linu= x device must > > > > > > have clock registered which matches the device in advance. > > > > > >=20 > > > > > > 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 ID= A here along > > > > > > with the cell name (or driver name). > > > > >=20 > > > > > I'm sure there are perfectly viable reasons for you doing thi= s. 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 waiti= ng all > > > > > this time. > > > > >=20 > > > > > 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. > > > > >=20 > > > > > Until that happens, I'm stuck! > > > >=20 > > > > Well, what if we had no one at hand to review that code? Would= that mean it > > > > would not be applicable forever? > > >=20 > > > No, but that's not the case is it? > > >=20 > > > I don't understand why Mike and Stephen aren't helping! > >=20 > > I'll wait until tomorrow and if we haven't heard anything I'll make= a > > decision. >=20 > OK, thanks! >=20 > 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= =2E >=20 > What's happening here is that Andy and Mika are taking the responsibi= lity > for fixing the new code if it turns out to be buggy and so it's their > problem if it happens to be broken. >=20 > And you can still revert commits that introduce bugs as a last resort= =2E 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). --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog