From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753364Ab2LSTA5 (ORCPT ); Wed, 19 Dec 2012 14:00:57 -0500 Received: from server.prisktech.co.nz ([115.188.14.127]:55041 "EHLO server.prisktech.co.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751997Ab2LSTAv (ORCPT ); Wed, 19 Dec 2012 14:00:51 -0500 Message-ID: <1355943649.2451.1.camel@gitbox> Subject: Re: Inconsistency in clk framework From: Tony Prisk To: Russell King - ARM Linux Cc: Mike Turquette , linux-kernel@vger.kernel.org, Arm Kernel Mailing List Date: Thu, 20 Dec 2012 08:00:49 +1300 In-Reply-To: <1355938492.27893.8.camel@gitbox> References: <1355890233.25599.4.camel@gitbox> <20121219092636.GW14363@n2100.arm.linux.org.uk> <1355938492.27893.8.camel@gitbox> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2012-12-20 at 06:34 +1300, Tony Prisk wrote: > On Wed, 2012-12-19 at 09:26 +0000, Russell King - ARM Linux wrote: > > On Wed, Dec 19, 2012 at 05:10:33PM +1300, Tony Prisk wrote: > > > Hi Mike, > > > > > > In attempting to remove some IS_ERR_OR_NULL references, it was pointed > > > out that clk_get() can return NULL if CONFIG_HAVE_CLK is not defined. > > > > That is correct - but why is that a problem? As far as users are > > concerned, NULL is a valid clock. If HAVE_CLK is undefined, do you > > want all your drivers to suddenly stop working? > > That will be where the misunderstanding has occurred - I didn't consider > NULL to be a valid clock. > > Given that NULL is a valid clock, I guess all tests against get_clk and > of_get_clk results should be IS_ERR_OR_NULL. Correct? > For the sake of clarity, I should rephrase: If the driver can't operate with a NULL clk, it should use a IS_ERR_OR_NULL test to test for failure, rather than IS_ERR. Regards Tony P