mirror of https://gitee.com/openkylin/linux.git
input: Add ChromeOS EC keyboard driver
Use the key-matrix layer to interpret key scan information from the EC and inject input based on the FDT-supplied key map. This driver registers itself with the ChromeOS EC driver to perform communications. The matrix-keypad FDT binding is used with a small addition to control ghosting. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Luigi Semenzato <semenzato@chromium.org> Signed-off-by: Vincent Palatin <vpalatin@chromium.org> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Simon Glass
Samuel Ortiz
parent
4384041533
commit
6af6dc2d2a
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@ -0,0 +1,72 @@
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ChromeOS EC Keyboard
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Google's ChromeOS EC Keyboard is a simple matrix keyboard implemented on
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a separate EC (Embedded Controller) device. It provides a message for reading
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key scans from the EC. These are then converted into keycodes for processing
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by the kernel.
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This binding is based on matrix-keymap.txt and extends/modifies it as follows:
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Required properties:
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- compatible: "google,cros-ec-keyb"
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Optional properties:
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- google,needs-ghost-filter: True to enable a ghost filter for the matrix
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keyboard. This is recommended if the EC does not have its own logic or
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hardware for this.
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Example:
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cros-ec-keyb {
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compatible = "google,cros-ec-keyb";
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keypad,num-rows = <8>;
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keypad,num-columns = <13>;
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google,needs-ghost-filter;
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/*
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* Keymap entries take the form of 0xRRCCKKKK where
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* RR=Row CC=Column KKKK=Key Code
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* The values below are for a US keyboard layout and
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* are taken from the Linux driver. Note that the
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* 102ND key is not used for US keyboards.
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*/
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linux,keymap = <
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/* CAPSLCK F1 B F10 */
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0x0001003a 0x0002003b 0x00030030 0x00040044
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/* N = R_ALT ESC */
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0x00060031 0x0008000d 0x000a0064 0x01010001
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/* F4 G F7 H */
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0x0102003e 0x01030022 0x01040041 0x01060023
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/* ' F9 BKSPACE L_CTRL */
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0x01080028 0x01090043 0x010b000e 0x0200001d
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/* TAB F3 T F6 */
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0x0201000f 0x0202003d 0x02030014 0x02040040
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/* ] Y 102ND [ */
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0x0205001b 0x02060015 0x02070056 0x0208001a
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/* F8 GRAVE F2 5 */
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0x02090042 0x03010029 0x0302003c 0x03030006
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/* F5 6 - \ */
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0x0304003f 0x03060007 0x0308000c 0x030b002b
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/* R_CTRL A D F */
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0x04000061 0x0401001e 0x04020020 0x04030021
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/* S K J ; */
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0x0404001f 0x04050025 0x04060024 0x04080027
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/* L ENTER Z C */
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0x04090026 0x040b001c 0x0501002c 0x0502002e
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/* V X , M */
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0x0503002f 0x0504002d 0x05050033 0x05060032
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/* L_SHIFT / . SPACE */
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0x0507002a 0x05080035 0x05090034 0x050B0039
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/* 1 3 4 2 */
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0x06010002 0x06020004 0x06030005 0x06040003
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/* 8 7 0 9 */
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0x06050009 0x06060008 0x0608000b 0x0609000a
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/* L_ALT DOWN RIGHT Q */
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0x060a0038 0x060b006c 0x060c006a 0x07010010
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/* E R W I */
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0x07020012 0x07030013 0x07040011 0x07050017
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/* U R_SHIFT P O */
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0x07060016 0x07070036 0x07080019 0x07090018
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/* UP LEFT */
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0x070b0067 0x070c0069>;
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};
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@ -628,4 +628,16 @@ config KEYBOARD_W90P910
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To compile this driver as a module, choose M here: the
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module will be called w90p910_keypad.
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config KEYBOARD_CROS_EC
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tristate "ChromeOS EC keyboard"
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select INPUT_MATRIXKMAP
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depends on MFD_CROS_EC
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help
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Say Y here to enable the matrix keyboard used by ChromeOS devices
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and implemented on the ChromeOS EC. You must enable one bus option
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(MFD_CROS_EC_I2C or MFD_CROS_EC_SPI) to use this.
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To compile this driver as a module, choose M here: the
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module will be called cros_ec_keyb.
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endif
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@ -11,6 +11,7 @@ obj-$(CONFIG_KEYBOARD_AMIGA) += amikbd.o
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obj-$(CONFIG_KEYBOARD_ATARI) += atakbd.o
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obj-$(CONFIG_KEYBOARD_ATKBD) += atkbd.o
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obj-$(CONFIG_KEYBOARD_BFIN) += bf54x-keys.o
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obj-$(CONFIG_KEYBOARD_CROS_EC) += cros_ec_keyb.o
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obj-$(CONFIG_KEYBOARD_DAVINCI) += davinci_keyscan.o
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obj-$(CONFIG_KEYBOARD_EP93XX) += ep93xx_keypad.o
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obj-$(CONFIG_KEYBOARD_GOLDFISH_EVENTS) += goldfish_events.o
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@ -0,0 +1,334 @@
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/*
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* ChromeOS EC keyboard driver
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*
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* Copyright (C) 2012 Google, Inc
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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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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* This driver uses the Chrome OS EC byte-level message-based protocol for
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* communicating the keyboard state (which keys are pressed) from a keyboard EC
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* to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
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* but everything else (including deghosting) is done here. The main
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* motivation for this is to keep the EC firmware as simple as possible, since
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* it cannot be easily upgraded and EC flash/IRAM space is relatively
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* expensive.
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/input.h>
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#include <linux/kernel.h>
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#include <linux/notifier.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/input/matrix_keypad.h>
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#include <linux/mfd/cros_ec.h>
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#include <linux/mfd/cros_ec_commands.h>
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/*
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* @rows: Number of rows in the keypad
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* @cols: Number of columns in the keypad
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* @row_shift: log2 or number of rows, rounded up
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* @keymap_data: Matrix keymap data used to convert to keyscan values
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* @ghost_filter: true to enable the matrix key-ghosting filter
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* @dev: Device pointer
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* @idev: Input device
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* @ec: Top level ChromeOS device to use to talk to EC
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* @event_notifier: interrupt event notifier for transport devices
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*/
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struct cros_ec_keyb {
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unsigned int rows;
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unsigned int cols;
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int row_shift;
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const struct matrix_keymap_data *keymap_data;
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bool ghost_filter;
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struct device *dev;
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struct input_dev *idev;
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struct cros_ec_device *ec;
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struct notifier_block notifier;
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};
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static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb *ckdev,
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uint8_t *buf, int row)
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{
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int pressed_in_row = 0;
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int row_has_teeth = 0;
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int col, mask;
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mask = 1 << row;
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for (col = 0; col < ckdev->cols; col++) {
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if (buf[col] & mask) {
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pressed_in_row++;
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row_has_teeth |= buf[col] & ~mask;
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if (pressed_in_row > 1 && row_has_teeth) {
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/* ghosting */
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dev_dbg(ckdev->dev,
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"ghost found at: r%d c%d, pressed %d, teeth 0x%x\n",
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row, col, pressed_in_row,
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row_has_teeth);
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return true;
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}
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}
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}
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return false;
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}
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/*
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* Returns true when there is at least one combination of pressed keys that
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* results in ghosting.
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*/
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static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
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{
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int row;
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/*
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* Ghosting happens if for any pressed key X there are other keys
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* pressed both in the same row and column of X as, for instance,
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* in the following diagram:
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*
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* . . Y . g .
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* . . . . . .
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* . . . . . .
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* . . X . Z .
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*
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* In this case only X, Y, and Z are pressed, but g appears to be
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* pressed too (see Wikipedia).
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*
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* We can detect ghosting in a single pass (*) over the keyboard state
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* by maintaining two arrays. pressed_in_row counts how many pressed
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* keys we have found in a row. row_has_teeth is true if any of the
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* pressed keys for this row has other pressed keys in its column. If
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* at any point of the scan we find that a row has multiple pressed
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* keys, and at least one of them is at the intersection with a column
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* with multiple pressed keys, we're sure there is ghosting.
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* Conversely, if there is ghosting, we will detect such situation for
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* at least one key during the pass.
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*
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* (*) This looks linear in the number of keys, but it's not. We can
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* cheat because the number of rows is small.
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*/
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for (row = 0; row < ckdev->rows; row++)
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if (cros_ec_keyb_row_has_ghosting(ckdev, buf, row))
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return true;
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return false;
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}
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/*
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* Compares the new keyboard state to the old one and produces key
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* press/release events accordingly. The keyboard state is 13 bytes (one byte
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* per column)
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*/
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static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
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uint8_t *kb_state, int len)
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{
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struct input_dev *idev = ckdev->idev;
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int col, row;
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int new_state;
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int num_cols;
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num_cols = len;
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if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
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/*
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* Simple-minded solution: ignore this state. The obvious
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* improvement is to only ignore changes to keys involved in
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* the ghosting, but process the other changes.
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*/
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dev_dbg(ckdev->dev, "ghosting found\n");
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return;
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}
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for (col = 0; col < ckdev->cols; col++) {
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for (row = 0; row < ckdev->rows; row++) {
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int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
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const unsigned short *keycodes = idev->keycode;
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int code;
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code = keycodes[pos];
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new_state = kb_state[col] & (1 << row);
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if (!!new_state != test_bit(code, idev->key)) {
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dev_dbg(ckdev->dev,
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"changed: [r%d c%d]: byte %02x\n",
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row, col, new_state);
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input_report_key(idev, code, new_state);
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}
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}
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}
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input_sync(ckdev->idev);
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}
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static int cros_ec_keyb_open(struct input_dev *dev)
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{
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struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
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return blocking_notifier_chain_register(&ckdev->ec->event_notifier,
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&ckdev->notifier);
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}
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static void cros_ec_keyb_close(struct input_dev *dev)
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{
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struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
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blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
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&ckdev->notifier);
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}
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static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
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{
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return ckdev->ec->command_recv(ckdev->ec, EC_CMD_MKBP_STATE,
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kb_state, ckdev->cols);
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}
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static int cros_ec_keyb_work(struct notifier_block *nb,
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unsigned long state, void *_notify)
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{
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int ret;
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struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
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notifier);
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uint8_t kb_state[ckdev->cols];
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ret = cros_ec_keyb_get_state(ckdev, kb_state);
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if (ret >= 0)
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cros_ec_keyb_process(ckdev, kb_state, ret);
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return NOTIFY_DONE;
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}
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/* Clear any keys in the buffer */
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static void cros_ec_keyb_clear_keyboard(struct cros_ec_keyb *ckdev)
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{
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uint8_t old_state[ckdev->cols];
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uint8_t new_state[ckdev->cols];
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unsigned long duration;
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int i, ret;
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/*
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* Keep reading until we see that the scan state does not change.
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* That indicates that we are done.
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*
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* Assume that the EC keyscan buffer is at most 32 deep.
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*/
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duration = jiffies;
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ret = cros_ec_keyb_get_state(ckdev, new_state);
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for (i = 1; !ret && i < 32; i++) {
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memcpy(old_state, new_state, sizeof(old_state));
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ret = cros_ec_keyb_get_state(ckdev, new_state);
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if (0 == memcmp(old_state, new_state, sizeof(old_state)))
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break;
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}
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duration = jiffies - duration;
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dev_info(ckdev->dev, "Discarded %d keyscan(s) in %dus\n", i,
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jiffies_to_usecs(duration));
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}
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static int cros_ec_keyb_probe(struct platform_device *pdev)
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{
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struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
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struct device *dev = ec->dev;
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struct cros_ec_keyb *ckdev;
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struct input_dev *idev;
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struct device_node *np;
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int err;
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np = pdev->dev.of_node;
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if (!np)
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return -ENODEV;
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ckdev = devm_kzalloc(&pdev->dev, sizeof(*ckdev), GFP_KERNEL);
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if (!ckdev)
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return -ENOMEM;
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err = matrix_keypad_parse_of_params(&pdev->dev, &ckdev->rows,
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&ckdev->cols);
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if (err)
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return err;
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idev = devm_input_allocate_device(&pdev->dev);
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if (!idev)
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return -ENOMEM;
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ckdev->ec = ec;
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ckdev->notifier.notifier_call = cros_ec_keyb_work;
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ckdev->dev = dev;
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dev_set_drvdata(&pdev->dev, ckdev);
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idev->name = ec->ec_name;
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idev->phys = ec->phys_name;
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__set_bit(EV_REP, idev->evbit);
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idev->id.bustype = BUS_VIRTUAL;
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idev->id.version = 1;
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idev->id.product = 0;
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idev->dev.parent = &pdev->dev;
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idev->open = cros_ec_keyb_open;
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idev->close = cros_ec_keyb_close;
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ckdev->ghost_filter = of_property_read_bool(np,
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"google,needs-ghost-filter");
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err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
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NULL, idev);
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if (err) {
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dev_err(dev, "cannot build key matrix\n");
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return err;
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}
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ckdev->row_shift = get_count_order(ckdev->cols);
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input_set_capability(idev, EV_MSC, MSC_SCAN);
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input_set_drvdata(idev, ckdev);
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ckdev->idev = idev;
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err = input_register_device(ckdev->idev);
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if (err) {
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dev_err(dev, "cannot register input device\n");
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return err;
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}
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int cros_ec_keyb_resume(struct device *dev)
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{
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struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
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/*
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* When the EC is not a wake source, then it could not have caused the
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* resume, so we clear the EC's key scan buffer. If the EC was a
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* wake source (e.g. the lid is open and the user might press a key to
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* wake) then the key scan buffer should be preserved.
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*/
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if (ckdev->ec->was_wake_device)
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cros_ec_keyb_clear_keyboard(ckdev);
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
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static struct platform_driver cros_ec_keyb_driver = {
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.probe = cros_ec_keyb_probe,
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.driver = {
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.name = "cros-ec-keyb",
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.pm = &cros_ec_keyb_pm_ops,
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},
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};
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module_platform_driver(cros_ec_keyb_driver);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
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MODULE_ALIAS("platform:cros-ec-keyb");
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