Fix the following sparse warning:

    drivers/platform/chrome/cros_ec_dev.c:64:45: sparse: Unknown escape '%'

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Olof Johansson <olofj@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Olof Johansson <olof@lixom.net>

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 <wfrichar@chromium.org>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

This adds the first few sysfs attributes for the Chrome OS EC. These
controls are made available under /sys/devices/virtual/chromeos/cros_ec

    flashinfo   - display current flash info
    reboot      - tell the EC to reboot in various ways
    version     - information about the EC software and hardware

Future changes will build on this to add additional controls.

From a root shell, you should be able to do things like this:

    cd /sys/devices/virtual/chromeos/cros_ec
    cat flashinfo
    cat version
    echo rw > reboot
    cat version
    echo ro > reboot
    cat version
    echo rw > reboot
    cat version
    echo cold > reboot

That last command will reboot the AP too.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

This patch adds a device interface to access the
Chrome OS Embedded Controller from user-space.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Simon Glass <sjg@google.com>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>