From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754337AbbG0QHF (ORCPT ); Mon, 27 Jul 2015 12:07:05 -0400 Received: from mga01.intel.com ([192.55.52.88]:53708 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752347AbbG0QHC (ORCPT ); Mon, 27 Jul 2015 12:07:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,555,1432623600"; d="scan'208";a="772138624" Date: Mon, 27 Jul 2015 19:04:47 +0300 From: Mika Westerberg To: Lee Jones 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: <20150727160447.GL1577@lahna.fi.intel.com> References: <1438009443-55317-1-git-send-email-andriy.shevchenko@linux.intel.com> <20150727152733.GB21114@x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150727152733.GB21114@x1> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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).