Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755946AbaKROWv (ORCPT ); Tue, 18 Nov 2014 09:22:51 -0500 Received: from mail-ie0-f181.google.com ([209.85.223.181]:41029 "EHLO mail-ie0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755196AbaKROWt (ORCPT ); Tue, 18 Nov 2014 09:22:49 -0500 Date: Tue, 18 Nov 2014 14:22:42 +0000 From: Lee Jones To: Javier Martinez Canillas Cc: Doug Anderson , Bill Richardson , Olof Johansson , Simon Glass , Gwendal Grignou , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] mfd: cros_ec: Expose Chrome OS Lightbar to users Message-ID: <20141118142242.GC24004@x1> References: <1416238213-15263-1-git-send-email-javier.martinez@collabora.co.uk> <1416238213-15263-4-git-send-email-javier.martinez@collabora.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1416238213-15263-4-git-send-email-javier.martinez@collabora.co.uk> 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 On Mon, 17 Nov 2014, Javier Martinez Canillas wrote: > From: Bill Richardson > > This adds some sysfs entries to provide userspace control of the > four-element LED "lightbar" on the Chromebook Pixel. This only instantiates > the lightbar controls if the device actually exists. > > To prevent DoS attacks, this interface is limited to 20 accesses/second, > although that rate can be adjusted by a privileged user. > > On Chromebooks without a lightbar, this should have no effect. On the > Chromebook Pixel, you should be able to do things like this: > > $ cd /sys/devices/virtual/chromeos/cros_ec/lightbar > $ echo 0x80 > brightness > $ echo 255 > brightness > $ > $ cat sequence > S0 > $ echo konami > sequence > $ cat sequence > KONAMI > $ > $ cat sequence > S0 > > And > > $ cd /sys/devices/virtual/chromeos/cros_ec/lightbar > $ echo stop > sequence > $ echo "4 255 255 255" > led_rgb > $ echo "0 255 0 0 1 0 255 0 2 0 0 255 3 255 255 0" > led_rgb > $ echo run > sequence > > Test the DoS prevention with this: > > $ cd /sys/devices/virtual/chromeos/cros_ec/lightbar > $ echo 500 > interval_msec > $ time (cat version version version version version version version) > > Signed-off-by: Bill Richardson > Reviewed-by: Olof Johansson > Tested-by: Doug Anderson > Reviewed-by: Benson Leung > Signed-off-by: Javier Martinez Canillas > --- > drivers/mfd/Makefile | 2 +- > drivers/mfd/cros_ec_dev.c | 2 + > drivers/mfd/cros_ec_dev.h | 3 + > drivers/mfd/cros_ec_lightbar.c | 347 +++++++++++++++++++++++++++++++++++++++++ By the sounds of the description, it doesn't seem as though this driver lives in MFD. I suggest another home, such as drivers/led. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/