diff options
| author | Bill Richardson <wfrichar@chromium.org> | 2015-02-02 14:26:28 +0300 |
|---|---|---|
| committer | Olof Johansson <olof@lixom.net> | 2015-02-27 02:45:16 +0300 |
| commit | f3f837e52b14bf84c2db65f622b5c31cd261100c (patch) | |
| tree | ea8c44173cd685e13f683fd63f205b9586a35fa9 /drivers/platform/chrome/cros_ec_dev.h | |
| parent | 71af4b52cc22a8d0f7b66a51427a804741a045b6 (diff) | |
| download | linux-f3f837e52b14bf84c2db65f622b5c31cd261100c.tar.xz | |
platform/chrome: Expose Chrome OS Lightbar to users
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>
Diffstat (limited to 'drivers/platform/chrome/cros_ec_dev.h')
| -rw-r--r-- | drivers/platform/chrome/cros_ec_dev.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_dev.h b/drivers/platform/chrome/cros_ec_dev.h index f03613290ecf..45d67f7e518c 100644 --- a/drivers/platform/chrome/cros_ec_dev.h +++ b/drivers/platform/chrome/cros_ec_dev.h @@ -47,4 +47,7 @@ struct cros_ec_readmem { void ec_dev_sysfs_init(struct cros_ec_device *); void ec_dev_sysfs_remove(struct cros_ec_device *); +void ec_dev_lightbar_init(struct cros_ec_device *); +void ec_dev_lightbar_remove(struct cros_ec_device *); + #endif /* _CROS_EC_DEV_H_ */ |