From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from caramon.arm.linux.org.uk ([78.32.30.218]:39131 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752987Ab3ACKFd (ORCPT ); Thu, 3 Jan 2013 05:05:33 -0500 Date: Thu, 3 Jan 2013 10:00:01 +0000 From: Russell King - ARM Linux To: Dan Carpenter Cc: Tony Prisk , Tomasz Stanislawski , Dan Carpenter , Sergei Shtylyov , kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Kyungmin Park , Sylwester Nawrocki , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Subject: Re: [PATCH RESEND 6/6] clk: s5p-g2d: Fix incorrect usage of IS_ERR_OR_NULL Message-ID: <20130103100000.GJ2631@n2100.arm.linux.org.uk> References: <1355852048-23188-1-git-send-email-linux@prisktech.co.nz> <1355852048-23188-7-git-send-email-linux@prisktech.co.nz> <50D62BC9.9010706@mvista.com> <50E32C06.5020104@gmail.com> <1357104713.30504.8.camel@gitbox> <20130103090520.GC7247@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130103090520.GC7247@mwanda> Sender: linux-media-owner@vger.kernel.org List-ID: On Thu, Jan 03, 2013 at 12:05:20PM +0300, Dan Carpenter wrote: > On Wed, Jan 02, 2013 at 06:31:53PM +1300, Tony Prisk wrote: > > Why should a _consumer_ of a clock care? It is _very_ important that > > people get this idea - to a consumer, the struct clk is just an opaque > > cookie. The fact that it appears to be a pointer does _not_ mean that > > the driver can do any kind of dereferencing on that pointer - it should > > never do so. > > > > Thread can be viewed here: > > https://lkml.org/lkml/2012/12/20/105 > > > > Ah. Grand. Thanks... > > Btw. The documentation for clk_get() really should include some of > this information. It *does* contain this information. The problem is that driver authors _ARE_ stupid, lazy morons who don't bother to read documentation. /** * clk_get - lookup and obtain a reference to a clock producer. * @dev: device for clock "consumer" * @id: clock consumer ID * * Returns a struct clk corresponding to the clock producer, or * valid IS_ERR() condition containing errno. The implementation * uses @dev and @id to determine the clock consumer, and thereby * the clock producer. (IOW, @id may be identical strings, but * clk_get may return different clock producers depending on @dev.) * * Drivers must assume that the clock source is not enabled. * * clk_get should not be called from within interrupt context. */