From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751788Ab2LUJNT (ORCPT ); Fri, 21 Dec 2012 04:13:19 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:38335 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751504Ab2LUJNN (ORCPT ); Fri, 21 Dec 2012 04:13:13 -0500 Date: Fri, 21 Dec 2012 09:13:06 +0000 From: Lee Jones To: Russell King - ARM Linux Cc: Linus Walleij , Steve Glendinning , Robert Marklund , linus.walleij@stericsson.com, arnd@arndb.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 4/4] net/smsc911x: Provide common clock functionality Message-ID: <20121221091306.GO2691@gmail.com> References: <1355937587-31730-1-git-send-email-lee.jones@linaro.org> <1355937587-31730-4-git-send-email-lee.jones@linaro.org> <20121220192441.GC14363@n2100.arm.linux.org.uk> <20121220203514.GN2691@gmail.com> <20121220205113.GD14363@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20121220205113.GD14363@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 Dec 2012, Russell King - ARM Linux wrote: > On Thu, Dec 20, 2012 at 08:35:14PM +0000, Lee Jones wrote: > > On Thu, 20 Dec 2012, Russell King - ARM Linux wrote: > > > > > On Thu, Dec 20, 2012 at 08:12:08PM +0100, Linus Walleij wrote: > > > > On Wed, Dec 19, 2012 at 6:19 PM, Lee Jones wrote: > > > > > > > > > Some platforms provide clocks which require enabling before the > > > > > SMSC911x chip will power on. This patch uses the new common clk > > > > > framework to do just that. If no clock is provided, it will just > > > > > be ignored and the driver will continue to assume that no clock > > > > > is required for the chip to run successfully. > > > > > > > > > > Cc: Steve Glendinning > > > > > Cc: netdev@vger.kernel.org > > > > > Signed-off-by: Lee Jones > > > > > > > > Seems to me like it'll do the trick. > > > > Acked-by: Linus Walleij > > > > > > This looks fairly dangerous. What about those platforms which use this > > > driver, but don't provide a clock for it? > > > > > > It looks like this will result in those platforms losing their ethernet > > > support. There's at least a bunch of the ARM evaluation boards which > > > make use of this driver... > > > > Right, but nothing should regress. If no clock is provided the driver > > moves on during the request and will refuse to prepare, enable and > > disable there after. > > > > Unless I've made a mistake somewhere? If so, I'd be happy to fixup. > > No, but... don't use NULL for that. Use IS_ERR(pdata->clk) instead. I'm a bit confused. I do use IS_ERR, then if there was a problem pdata->clk is set to NULL, then we test for NULL thereafter: > /* Request clock */ > pdata->clk = clk_get(&pdev->dev, NULL); > if (IS_ERR(pdata->clk)) { > netdev_warn(ndev, "couldn't get clock %d\n", PTR_ERR(pdata->clk)); > pdata->clk = NULL; > } Are you saying remove "pdata->clk = NULL;" and test for IS_ERR every time? -- Lee Jones Linaro ST-Ericsson Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog