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: NBill Richardson <wfrichar@chromium.org>
Reviewed-by: NOlof Johansson <olofj@chromium.org>
Tested-by: NDoug Anderson <dianders@chromium.org>
Reviewed-by: NBenson Leung <bleung@chromium.org>
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: NGwendal Grignou <gwendal@chromium.org>
Reviewed-by: NGwendal Grignou <gwendal@chromium.org>
Signed-off-by: NOlof 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: NBill Richardson <wfrichar@chromium.org>
Reviewed-by: NOlof Johansson <olofj@chromium.org>
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: NGwendal Grignou <gwendal@chromium.org>
Reviewed-by: NGwendal Grignou <gwendal@chromium.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

This patch adds a device interface to access the
Chrome OS Embedded Controller from user-space.
Signed-off-by: NBill Richardson <wfrichar@chromium.org>
Reviewed-by: NSimon Glass <sjg@google.com>
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: NGwendal Grignou <gwendal@chromium.org>
Tested-by: NGwendal Grignou <gwendal@chromium.org>
Reviewed-by: NGwendal Grignou <gwendal@chromium.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

Chromebooks have an Embedded Controller (EC) that is used to
implement various functions such as keyboard, power and battery.

The AP can communicate with the EC through different bus types
such as I2C, SPI or LPC.

The cros_ec mfd driver is then composed of a core driver that
register the sub-devices as mfd cells and provide a high level
communication interface that is used by the rest of the kernel
and bus specific interfaces modules.

Each connection method then has its own driver, which register
with the EC driver interface-agnostic interface.

Currently, there are drivers to communicate with the EC over
I2C and SPI and this driver adds support for LPC.
Signed-off-by: NBill Richardson <wfrichar@chromium.org>
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: NGwendal Grignou <gwendal@chromium.org>
Reviewed-by: NGwendal Grignou <gwendal@chromium.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

Add the ramoops pstore device so that we get logs of panics across reboots.
Signed-off-by: NOlof Johansson <olof@lixom.net>

It makes sense to split out the Chromebook/Chromebox hardware platform
drivers to a separate subdirectory, since some of it will be shared
between ARM and x86.

This moves over the existing chromeos_laptop driver without making
any other changes, and adds appropriate Kconfig entries for the new
directory. It also adds a MAINTAINERS entry for the new subdir.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NMatthew Garrett <matthew.garrett@nebula.com>