From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752840Ab2DGV4r (ORCPT ); Sat, 7 Apr 2012 17:56:47 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:44580 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751324Ab2DGV4q (ORCPT ); Sat, 7 Apr 2012 17:56:46 -0400 Date: Sat, 7 Apr 2012 14:56:41 -0700 From: Dmitry Torokhov To: Shuah Khan Cc: Andrew Morton , neilb@suse.de, rpurdie@linux.intel.com, LKML Subject: Re: [PATCH RESEND] LEDS-One-Shot-Timer-Trigger-implementation Message-ID: <20120407215641.GA4539@core.coreip.homeip.net> References: <1333310039.2879.4.camel@lorien2> <20120406165353.ab667eb0.akpm@linux-foundation.org> <1333808024.2728.39.camel@lorien2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1333808024.2728.39.camel@lorien2> 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 Hi Shuah, On Sat, Apr 07, 2012 at 08:13:44AM -0600, Shuah Khan wrote: > > > > +This feature will help implement vibrate functionality which requires one > > > +time activation of vibrate mode without a continuous vibrate on/off cycles. > > > > They make vibrating LED? ;) > > > > What's going on here? You're proposing to repurpose the LEDs code to > > drive vibration devices? Or some devices couple a LED with a vibration > > device? > > I owe you filling in the blanks type explanation. Let me describe the > use-case I am trying to address first. Vibrater function on phones is > implemented using PWM pins on SoC or PMIC. When there is no such > hardware present, a software solution is needed. Currently two drivers > timed-gpio and timed-output (under staging/android in Linux 3.3) > together implement the software vibrate feature. The main functionality > it implements is the one time enables of timer to prevent user space > crashes leaving the phone in vibrate mode causing the battery to drain. > leds as it is implemented currently, is not suitable to address this > use-case as it doesn't support one time enables. So why do not you use memoryless force feedback framework that other devices use (see drivers/input/misc/*vibra.c drivers). Thanks. -- Dmitry