Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933640Ab3GPRIW (ORCPT ); Tue, 16 Jul 2013 13:08:22 -0400 Received: from 12.mo1.mail-out.ovh.net ([87.98.162.229]:42829 "EHLO mo1.mail-out.ovh.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933397Ab3GPRIU (ORCPT ); Tue, 16 Jul 2013 13:08:20 -0400 Message-ID: <51E57DFC.5030302@overkiz.com> Date: Tue, 16 Jul 2013 19:08:12 +0200 From: boris brezillon User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Alan Stern CC: Nicolas Ferre , Ludovic Desroches , Jean-Christophe Plagniol-Villard , Greg Kroah-Hartman , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org X-Ovh-Mailout: 178.32.228.1 (mo1.mail-out.ovh.net) Subject: Re: [PATCH v3 6/7] USB: ohci-at91: add usb_clk for transition to common clk framework References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Ovh-Tracer-Id: 9071657025925380198 X-Ovh-Remote: 78.236.240.82 (cha74-5-78-236-240-82.fbx.proxad.net) X-Ovh-Local: 213.186.33.20 (ns0.ovh.net) X-OVH-SPAMSTATE: OK X-OVH-SPAMSCORE: -100 X-OVH-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeijedrvdefucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd X-Spam-Check: DONE|U 0.5/N X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeijedrvdefucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2067 Lines: 54 Hello Alan, On 16/07/2013 18:48, Alan Stern wrote: > On Tue, 16 Jul 2013, Boris BREZILLON wrote: > >> The AT91 PMC (Power Management Controller) provides an USB clock used by >> USB Full Speed host (ohci) and USB Full Speed device (udc). >> The usb drivers (ohci and udc) must configure this clock to 48Mhz. >> This configuration was formely done in mach-at91/clock.c, but this >> implementation will be removed when moving to common clk framework. >> >> This patch add support for usb clock retrieval and configuration, and is >> backward compatible with the current at91 clk implementation (if usb clk >> is not found, it does not configure/enable the usb clk). > But it does print a warning in the system log, right? Yes it does. > >> @@ -144,6 +150,11 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver, >> goto err2; >> } >> >> + uclk = clk_get(&pdev->dev, "usb_clk"); >> + if (IS_ERR(uclk)) { >> + uclk = NULL; >> + dev_warn(&pdev->dev, "failed to get usb_clk\n"); >> + } > Is this really what you want for backward compatibility? Here are some proposition to remove the warning message: 1) replace it with a dev_info and change the message: dev_info(&pdev->dev, "failed to get usb_clk (most likely using old at91 clk implementation)\n"); 2) drop the log and silently ignore the missing clk (I'm not a big fan of this solution as it may lead to some errors if we're using new clk implem and the clock is really missing) 3) rework the current clk_set_rate function to accept clk_set_rate on usb clk and add clk_lookup entries for the usb clk (I'm not a big fan of this solution neither as this modifications will only be used for a short time until the transition to common clk framework is completed). > Alan Stern > Thanks for your review. Best Regards, Boris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/