From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752901AbbHaIIM (ORCPT <rfc822;w@1wt.eu>);
	Mon, 31 Aug 2015 04:08:12 -0400
Received: from lb3-smtp-cloud2.xs4all.net ([194.109.24.29]:56857 "EHLO
	lb3-smtp-cloud2.xs4all.net" rhost-flags-OK-OK-OK-OK)
	by vger.kernel.org with ESMTP id S1752036AbbHaIIK (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 31 Aug 2015 04:08:10 -0400
Message-ID: <1441008481.8272.10.camel@tiscali.nl>
Subject: Re: [PATCH 3/7] dmaengine: st_fdma: Add STMicroelectronics FDMA
 engine driver support
From: Paul Bolle <pebolle@tiscali.nl>
To: Maxime Coquelin <maxime.coquelin@st.com>,
        Peter Griffin <peter.griffin@linaro.org>
Cc: lee.jones@linaro.org, devicetree@vger.kernel.org,
        dmaengine@vger.kernel.org, ludovic.barre@st.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        srinivas.kandagatla@gmail.com, patrice.chotard@st.com,
        vinod.koul@intel.com, dan.j.williams@intel.com
Date: Mon, 31 Aug 2015 10:08:01 +0200
In-Reply-To: <55E40715.1040204@st.com>
References: <1436371888-27863-1-git-send-email-peter.griffin@linaro.org>
	 <1436371888-27863-4-git-send-email-peter.griffin@linaro.org>
	 <1436429872.20619.77.camel@tiscali.nl> <55E40715.1040204@st.com>
Content-Type: text/plain; charset="UTF-8"
X-Mailer: Evolution 3.16.5 (3.16.5-1.fc22) 
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Maxime,

On ma, 2015-08-31 at 09:49 +0200, Maxime Coquelin wrote:
> On 07/09/2015 10:17 AM, Paul Bolle wrote:
> > > > +static int __exit st_fdma_remove(struct platform_device *pdev)
> > > > +{
> > > > +	struct st_fdma_dev *fdev = platform_get_drvdata(pdev);
> > > > +
> > > > +	wait_for_completion(&fdev->fw_ack);
> > > > +
> > > > +	st_fdma_clk_disable(fdev);
> > > > +
> > > > +	return 0;
> > > > +}
> > Since this driver is built-in only this means st_fdma_remove() can 
> > never be used, right?

> It's not because a driver is built-in only that it does not need a 
> remove callback.
> An instance can be probed/removed any time via driver's bind/unbind 
> SysFS entries.
> Am I missing something?

(This discussion is moot because Peter already stated that a new version
will be modular.)

It follows from the __exit tag that st_fdma_remove() should never be
part of the kernel image (in this version of the patch), doesn't it?

(I don't know what happens in this situation if an unbind sysfs entry is
used to remove a driver. I've never tried that.)


Paul Bolle