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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>
54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
/*
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* cros_ec_dev - expose the Chrome OS Embedded Controller to userspace
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*
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* Copyright (C) 2014 Google, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _CROS_EC_DEV_H_
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#define _CROS_EC_DEV_H_
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#include <linux/ioctl.h>
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#include <linux/types.h>
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#include <linux/mfd/cros_ec.h>
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#define CROS_EC_DEV_NAME "cros_ec"
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#define CROS_EC_DEV_VERSION "1.0.0"
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/*
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* @offset: within EC_LPC_ADDR_MEMMAP region
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* @bytes: number of bytes to read. zero means "read a string" (including '\0')
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* (at most only EC_MEMMAP_SIZE bytes can be read)
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* @buffer: where to store the result
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* ioctl returns the number of bytes read, negative on error
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*/
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struct cros_ec_readmem {
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uint32_t offset;
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uint32_t bytes;
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uint8_t buffer[EC_MEMMAP_SIZE];
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};
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#define CROS_EC_DEV_IOC 0xEC
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#define CROS_EC_DEV_IOCXCMD _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
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#define CROS_EC_DEV_IOCRDMEM _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)
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void ec_dev_sysfs_init(struct cros_ec_device *);
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void ec_dev_sysfs_remove(struct cros_ec_device *);
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void ec_dev_lightbar_init(struct cros_ec_device *);
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void ec_dev_lightbar_remove(struct cros_ec_device *);
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#endif /* _CROS_EC_DEV_H_ */
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