From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752370Ab2A0RF7 (ORCPT ); Fri, 27 Jan 2012 12:05:59 -0500 Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:48068 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751368Ab2A0RF4 (ORCPT ); Fri, 27 Jan 2012 12:05:56 -0500 X-Mail-Handler: MailHop Outbound by DynDNS X-Originating-IP: 98.234.237.12 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/mailhop/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX1/Za9fBKBZHt1KS3UFJxqUc Date: Fri, 27 Jan 2012 09:05:45 -0800 From: Tony Lindgren To: Shawn Guo Cc: Stephen Warren , Dong Aisheng , "devicetree-discuss@lists.ozlabs.org" , "Linus Walleij (linus.walleij@linaro.org)" , "linux-kernel@vger.kernel.org" , "rob.herring@calxeda.com" , "Grant Likely (grant.likely@secretlab.ca)" , Thomas Abraham , "kernel@pengutronix.de" , "Simon Glass (sjg@chromium.org)" , "cjb@laptop.org" , Dong Aisheng-B29396 , "Sascha Hauer (s.hauer@pengutronix.de)" , "linux-arm-kernel@lists.infradead.org" Subject: Re: Pinmux bindings proposal V2 Message-ID: <20120127170545.GH13504@atomide.com> References: <74CDBE0F657A3D45AFBB94109FB122FF1780DAB4CE@HQMAIL01.nvidia.com> <20120123210052.GS22818@atomide.com> <74CDBE0F657A3D45AFBB94109FB122FF178CB81C0D@HQMAIL01.nvidia.com> <20120124012038.GT22818@atomide.com> <74CDBE0F657A3D45AFBB94109FB122FF178CB81EDB@HQMAIL01.nvidia.com> <20120125000407.GU22818@atomide.com> <74CDBE0F657A3D45AFBB94109FB122FF178CB82433@HQMAIL01.nvidia.com> <20120127020832.GJ29812@atomide.com> <20120127065752.GB32740@S2101-09.ap.freescale.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120127065752.GB32740@S2101-09.ap.freescale.net> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, * Shawn Guo [120126 22:15]: > On Thu, Jan 26, 2012 at 06:08:33PM -0800, Tony Lindgren wrote: > > * Stephen Warren [120126 11:03]: > ... > > > Second, as I mentioned before, while some of the states are certainly > > > PM-related, I don't think all will be, e.g. the case of running an SD > > > controller at different clock rates to the SD card, and needing to > > > set different pin parameters based on the clock rate. Is runtime PM > > > intended cover that kind of thing? The idea here is that the common > > > pinctrl binding can allow the driver to require different named states > > > for those different clock rate cases. > > > > For the PM related states, those should be Linux generic. For rate > > setting sounds like that's really something you should set up as clocks > > in the Tegra wrapper driver for SDHCI? > > > That's right. > > > Ideally the SDHCI driver would be completely arch independent, and > > then the SoC specific wrapper driver would know how to communicate to > > the pinmux/pinconf framwork or clock framework what it needs using > > Linux generic APIs. > > But that wrapper driver should not be bothered to call pinmux/pinconf > APIs on pin basis to change the pinctrl configuration. The elegant > way would be something like the following in case that it switches > the bus frequency from 50 MHz to 100 MHz. > > pmx = pinmux_get(dev, "esdhc_50mhz"); > ... > pinmux_put(pmx); > pmx = pinmux_get(dev, "esdhc_100mhz"); > ... > > The specific mux and config settings of states esdhc_50mhz and > esdhc_100mhz would be retrieved from device tree. Yes whatever mux names can be used, same as with clock framework for clock names. But that means you'll have to constantly get/put the mux which is not efficient. Wouldn't it be cleaner to just clk_get esdhc_clk during init, then do clk_set_rate on it to toggle the rates? > > So I'd rather stay out of random named states for > > the pins coming from device tree; If we still need them, they should > > be common bindings rather than things like "xyz_clock_hack". > > > The binding defines the syntax, and I do not see the necessity to > force the particular state name, which is really pinctrl client > device specific. Do you have some other custom pin state example other than the clock rate change example above? Regards, Tony