From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH 2/5] input: twl6040-vibra: add handler to unregister input if module is removed Date: Tue, 19 Apr 2016 00:57:05 -0700 Message-ID: <20160419075705.GA13933@dtor-ws> References: <89f53877b821049c789256dd1b0c0b1dbb604de9.1461009340.git.hns@goldelico.com> <20160418211257.GA1006@dtor-ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: "H. Nikolaus Schaller" Cc: Fabio Estevam , Peter Ujfalusi , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pyra-handheld.com, letux-kernel@openphoenux.org List-Id: linux-input@vger.kernel.org On Tue, Apr 19, 2016 at 09:33:10AM +0200, H. Nikolaus Schaller wrote: > > > Am 18.04.2016 um 23:12 schrieb Dmitry Torokhov : > > > > On Mon, Apr 18, 2016 at 09:55:38PM +0200, H. Nikolaus Schaller wrote: > >> commit 1f9e1470ab34 ("Input: twl6040-vibra - use devm functions") > >> > >> converted everything to devm but we still need to call > >> input_unregister_device(info->input_dev) > > > > No, this is not needed, because devm-managed input devices will be > > unregistered automatically. > > Well, it would, if the current driver would use devm for registration. But it appears not to do it that way (line 375): > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/input/misc/twl6040-vibra.c?id=refs/tags/v4.6-rc4#n375 > > So we either have to fix line 375 or add the proposed explicit unregister call. > > Research shows me that you did propose devm_input_register_device() some years ago but this API was never included: > > https://lkml.org/lkml/2012/10/29/855 That's because we have what I mentioned in _OR_ portion of that email: /** * devm_input_allocate_device - allocate managed input device * @dev: device owning the input device being created * * Returns prepared struct input_dev or %NULL. * * Managed input devices do not need to be explicitly unregistered or ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * freed as it will be done automatically when owner device unbinds from * its driver (or binding fails). Once managed input device is allocated, * it is ready to be set up and registered in the same fashion as regular * input device. There are no special devm_input_device_[un]register() * variants, regular ones work with both managed and unmanaged devices, * should you need them. In most cases however, managed input device need * not be explicitly unregistered or freed. * * NOTE: the owner device is set up as parent of input device and users * should not override it. */ Thanks. -- Dmitry