Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932170AbaDYOP0 (ORCPT ); Fri, 25 Apr 2014 10:15:26 -0400 Received: from top.free-electrons.com ([176.31.233.9]:47589 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752861AbaDYOPV (ORCPT ); Fri, 25 Apr 2014 10:15:21 -0400 Date: Fri, 25 Apr 2014 16:15:17 +0200 From: Thomas Petazzoni To: Gregory CLEMENT Cc: Mathias Nyman , Greg Kroah-Hartman , Felipe Balbi , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Lior Amsalem , Tawfik Bayouk , devicetree@vger.kernel.org, Nadav Haklai , Rob Herring , Ezequiel Garcia , Grant Likely , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 02/18] usb: host: xhci-plat: Add clocks support Message-ID: <20140425161517.20821c65@skate> In-Reply-To: <1398434836-18908-3-git-send-email-gregory.clement@free-electrons.com> References: <1398434836-18908-1-git-send-email-gregory.clement@free-electrons.com> <1398434836-18908-3-git-send-email-gregory.clement@free-electrons.com> Organization: Free Electrons X-Mailer: Claws Mail 3.9.1 (GTK+ 2.24.20; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dear Gregory CLEMENT, On Fri, 25 Apr 2014 16:07:00 +0200, Gregory CLEMENT wrote: > Some platform (such as the Armada 38x ones) can gate the clock of > their USB controller. This patch add the support for the clock, by > enabling them during probe and disabling them on remove. > > As not all platforms have clock support then enabling and disabling > the clocks have been placed in separate functions. Then if the clocks > are not supported we still can use the same calls, and there is no > > Signed-off-by: Gregory CLEMENT > --- > drivers/usb/host/xhci-plat.c | 52 ++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 50 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c > index f5351af4b2c5..bb5d563f729c 100644 > --- a/drivers/usb/host/xhci-plat.c > +++ b/drivers/usb/host/xhci-plat.c > @@ -11,6 +11,7 @@ > * version 2 as published by the Free Software Foundation. > */ > > +#include > #include > #include > #include > @@ -85,6 +86,42 @@ static const struct hc_driver xhci_plat_xhci_driver = { > .bus_resume = xhci_bus_resume, > }; > > +#if defined(CONFIG_HAVE_CLK) > +static int try_enable_clk(struct platform_device *pdev) > +{ > + struct clk *clk = devm_clk_get(&pdev->dev, NULL); > + > + /* Not all platforms have a clk so it is not an error if the clock > + does not exists. */ > + if (!IS_ERR(clk)) Instead, do: if (IS_ERR(clk)) return 0; return clk_prepare_enable(clk); > + if (clk_prepare_enable(clk)) > + return -ENODEV; > + return 0; > +} > + > +static int try_disable_clk(struct platform_device *pdev) > +{ > + struct clk *clk = devm_clk_get(&pdev->dev, NULL); No, this isn't correct: you shouldn't be getting the clock to disable/unprepare it, otherwise you have an unbalanced number of get()/put() calls on the clocks. Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- 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/