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input: Add ChromeOS EC keyboard driver

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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 2013-02-25 14:08:41 -08:00 committed by Samuel Ortiz
parent 4384041533
commit 6af6dc2d2a
4 changed files with 419 additions and 0 deletions
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72
Documentation/devicetree/bindings/input/cros-ec-keyb.txt Normal file
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@ -0,0 +1,72 @@
ChromeOS EC Keyboard
Google's ChromeOS EC Keyboard is a simple matrix keyboard implemented on
a separate EC (Embedded Controller) device. It provides a message for reading
key scans from the EC. These are then converted into keycodes for processing
by the kernel.
This binding is based on matrix-keymap.txt and extends/modifies it as follows:
Required properties:
- compatible: "google,cros-ec-keyb"
Optional properties:
- google,needs-ghost-filter: True to enable a ghost filter for the matrix
keyboard. This is recommended if the EC does not have its own logic or
hardware for this.
Example:
cros-ec-keyb {
compatible = "google,cros-ec-keyb";
keypad,num-rows = <8>;
keypad,num-columns = <13>;
google,needs-ghost-filter;
/*
* Keymap entries take the form of 0xRRCCKKKK where
* RR=Row CC=Column KKKK=Key Code
* The values below are for a US keyboard layout and
* are taken from the Linux driver. Note that the
* 102ND key is not used for US keyboards.
*/
linux,keymap = <
/* CAPSLCK F1 B F10 */
0x0001003a 0x0002003b 0x00030030 0x00040044
/* N = R_ALT ESC */
0x00060031 0x0008000d 0x000a0064 0x01010001
/* F4 G F7 H */
0x0102003e 0x01030022 0x01040041 0x01060023
/* ' F9 BKSPACE L_CTRL */
0x01080028 0x01090043 0x010b000e 0x0200001d
/* TAB F3 T F6 */
0x0201000f 0x0202003d 0x02030014 0x02040040
/* ] Y 102ND [ */
0x0205001b 0x02060015 0x02070056 0x0208001a
/* F8 GRAVE F2 5 */
0x02090042 0x03010029 0x0302003c 0x03030006
/* F5 6 - \ */
0x0304003f 0x03060007 0x0308000c 0x030b002b
/* R_CTRL A D F */
0x04000061 0x0401001e 0x04020020 0x04030021
/* S K J ; */
0x0404001f 0x04050025 0x04060024 0x04080027
/* L ENTER Z C */
0x04090026 0x040b001c 0x0501002c 0x0502002e
/* V X , M */
0x0503002f 0x0504002d 0x05050033 0x05060032
/* L_SHIFT / . SPACE */
0x0507002a 0x05080035 0x05090034 0x050B0039
/* 1 3 4 2 */
0x06010002 0x06020004 0x06030005 0x06040003
/* 8 7 0 9 */
0x06050009 0x06060008 0x0608000b 0x0609000a
/* L_ALT DOWN RIGHT Q */
0x060a0038 0x060b006c 0x060c006a 0x07010010
/* E R W I */
0x07020012 0x07030013 0x07040011 0x07050017
/* U R_SHIFT P O */
0x07060016 0x07070036 0x07080019 0x07090018
/* UP LEFT */
0x070b0067 0x070c0069>;
};

12
drivers/input/keyboard/Kconfig
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@ -628,4 +628,16 @@ config KEYBOARD_W90P910
To compile this driver as a module, choose M here: the
module will be called w90p910_keypad.
config KEYBOARD_CROS_EC
tristate "ChromeOS EC keyboard"
select INPUT_MATRIXKMAP
depends on MFD_CROS_EC
help
Say Y here to enable the matrix keyboard used by ChromeOS devices
and implemented on the ChromeOS EC. You must enable one bus option
(MFD_CROS_EC_I2C or MFD_CROS_EC_SPI) to use this.
To compile this driver as a module, choose M here: the
module will be called cros_ec_keyb.
endif

1
drivers/input/keyboard/Makefile
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@ -11,6 +11,7 @@ obj-$(CONFIG_KEYBOARD_AMIGA) += amikbd.o
obj-$(CONFIG_KEYBOARD_ATARI) += atakbd.o
obj-$(CONFIG_KEYBOARD_ATKBD) += atkbd.o
obj-$(CONFIG_KEYBOARD_BFIN) += bf54x-keys.o
obj-$(CONFIG_KEYBOARD_CROS_EC) += cros_ec_keyb.o
obj-$(CONFIG_KEYBOARD_DAVINCI) += davinci_keyscan.o
obj-$(CONFIG_KEYBOARD_EP93XX) += ep93xx_keypad.o
obj-$(CONFIG_KEYBOARD_GOLDFISH_EVENTS) += goldfish_events.o

334
drivers/input/keyboard/cros_ec_keyb.c Normal file
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@ -0,0 +1,334 @@
/*
* ChromeOS EC keyboard driver
*
* Copyright (C) 2012 Google, Inc
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* This driver uses the Chrome OS EC byte-level message-based protocol for
* communicating the keyboard state (which keys are pressed) from a keyboard EC
* to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
* but everything else (including deghosting) is done here. The main
* motivation for this is to keep the EC firmware as simple as possible, since
* it cannot be easily upgraded and EC flash/IRAM space is relatively
* expensive.
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/kernel.h>
#include <linux/notifier.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/input/matrix_keypad.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
/*
* @rows: Number of rows in the keypad
* @cols: Number of columns in the keypad
* @row_shift: log2 or number of rows, rounded up
* @keymap_data: Matrix keymap data used to convert to keyscan values
* @ghost_filter: true to enable the matrix key-ghosting filter
* @dev: Device pointer
* @idev: Input device
* @ec: Top level ChromeOS device to use to talk to EC
* @event_notifier: interrupt event notifier for transport devices
*/
struct cros_ec_keyb {
unsigned int rows;
unsigned int cols;
int row_shift;
const struct matrix_keymap_data *keymap_data;
bool ghost_filter;
struct device *dev;
struct input_dev *idev;
struct cros_ec_device *ec;
struct notifier_block notifier;
};
static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb *ckdev,
uint8_t *buf, int row)
{
int pressed_in_row = 0;
int row_has_teeth = 0;
int col, mask;
mask = 1 << row;
for (col = 0; col < ckdev->cols; col++) {
if (buf[col] & mask) {
pressed_in_row++;
row_has_teeth |= buf[col] & ~mask;
if (pressed_in_row > 1 && row_has_teeth) {
/* ghosting */
dev_dbg(ckdev->dev,
"ghost found at: r%d c%d, pressed %d, teeth 0x%x\n",
row, col, pressed_in_row,
row_has_teeth);
return true;
}
}
}
return false;
}
/*
* Returns true when there is at least one combination of pressed keys that
* results in ghosting.
*/
static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
{
int row;
/*
* Ghosting happens if for any pressed key X there are other keys
* pressed both in the same row and column of X as, for instance,
* in the following diagram:
*
* . . Y . g .
* . . . . . .
* . . . . . .
* . . X . Z .
*
* In this case only X, Y, and Z are pressed, but g appears to be
* pressed too (see Wikipedia).
*
* We can detect ghosting in a single pass (*) over the keyboard state
* by maintaining two arrays. pressed_in_row counts how many pressed
* keys we have found in a row. row_has_teeth is true if any of the
* pressed keys for this row has other pressed keys in its column. If
* at any point of the scan we find that a row has multiple pressed
* keys, and at least one of them is at the intersection with a column
* with multiple pressed keys, we're sure there is ghosting.
* Conversely, if there is ghosting, we will detect such situation for
* at least one key during the pass.
*
* (*) This looks linear in the number of keys, but it's not. We can
* cheat because the number of rows is small.
*/
for (row = 0; row < ckdev->rows; row++)
if (cros_ec_keyb_row_has_ghosting(ckdev, buf, row))
return true;
return false;
}
/*
* Compares the new keyboard state to the old one and produces key
* press/release events accordingly. The keyboard state is 13 bytes (one byte
* per column)
*/
static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
uint8_t *kb_state, int len)
{
struct input_dev *idev = ckdev->idev;
int col, row;
int new_state;
int num_cols;
num_cols = len;
if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
/*
* Simple-minded solution: ignore this state. The obvious
* improvement is to only ignore changes to keys involved in
* the ghosting, but process the other changes.
*/
dev_dbg(ckdev->dev, "ghosting found\n");
return;
}
for (col = 0; col < ckdev->cols; col++) {
for (row = 0; row < ckdev->rows; row++) {
int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
const unsigned short *keycodes = idev->keycode;
int code;
code = keycodes[pos];
new_state = kb_state[col] & (1 << row);
if (!!new_state != test_bit(code, idev->key)) {
dev_dbg(ckdev->dev,
"changed: [r%d c%d]: byte %02x\n",
row, col, new_state);
input_report_key(idev, code, new_state);
}
}
}
input_sync(ckdev->idev);
}
static int cros_ec_keyb_open(struct input_dev *dev)
{
struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
return blocking_notifier_chain_register(&ckdev->ec->event_notifier,
&ckdev->notifier);
}
static void cros_ec_keyb_close(struct input_dev *dev)
{
struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
&ckdev->notifier);
}
static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
{
return ckdev->ec->command_recv(ckdev->ec, EC_CMD_MKBP_STATE,
kb_state, ckdev->cols);
}
static int cros_ec_keyb_work(struct notifier_block *nb,
unsigned long state, void *_notify)
{
int ret;
struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
notifier);
uint8_t kb_state[ckdev->cols];
ret = cros_ec_keyb_get_state(ckdev, kb_state);
if (ret >= 0)
cros_ec_keyb_process(ckdev, kb_state, ret);
return NOTIFY_DONE;
}
/* Clear any keys in the buffer */
static void cros_ec_keyb_clear_keyboard(struct cros_ec_keyb *ckdev)
{
uint8_t old_state[ckdev->cols];
uint8_t new_state[ckdev->cols];
unsigned long duration;
int i, ret;
/*
* Keep reading until we see that the scan state does not change.
* That indicates that we are done.
*
* Assume that the EC keyscan buffer is at most 32 deep.
*/
duration = jiffies;
ret = cros_ec_keyb_get_state(ckdev, new_state);
for (i = 1; !ret && i < 32; i++) {
memcpy(old_state, new_state, sizeof(old_state));
ret = cros_ec_keyb_get_state(ckdev, new_state);
if (0 == memcmp(old_state, new_state, sizeof(old_state)))
break;
}
duration = jiffies - duration;
dev_info(ckdev->dev, "Discarded %d keyscan(s) in %dus\n", i,
jiffies_to_usecs(duration));
}
static int cros_ec_keyb_probe(struct platform_device *pdev)
{
struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
struct device *dev = ec->dev;
struct cros_ec_keyb *ckdev;
struct input_dev *idev;
struct device_node *np;
int err;
np = pdev->dev.of_node;
if (!np)
return -ENODEV;
ckdev = devm_kzalloc(&pdev->dev, sizeof(*ckdev), GFP_KERNEL);
if (!ckdev)
return -ENOMEM;
err = matrix_keypad_parse_of_params(&pdev->dev, &ckdev->rows,
&ckdev->cols);
if (err)
return err;
idev = devm_input_allocate_device(&pdev->dev);
if (!idev)
return -ENOMEM;
ckdev->ec = ec;
ckdev->notifier.notifier_call = cros_ec_keyb_work;
ckdev->dev = dev;
dev_set_drvdata(&pdev->dev, ckdev);
idev->name = ec->ec_name;
idev->phys = ec->phys_name;
__set_bit(EV_REP, idev->evbit);
idev->id.bustype = BUS_VIRTUAL;
idev->id.version = 1;
idev->id.product = 0;
idev->dev.parent = &pdev->dev;
idev->open = cros_ec_keyb_open;
idev->close = cros_ec_keyb_close;
ckdev->ghost_filter = of_property_read_bool(np,
"google,needs-ghost-filter");
err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
NULL, idev);
if (err) {
dev_err(dev, "cannot build key matrix\n");
return err;
}
ckdev->row_shift = get_count_order(ckdev->cols);
input_set_capability(idev, EV_MSC, MSC_SCAN);
input_set_drvdata(idev, ckdev);
ckdev->idev = idev;
err = input_register_device(ckdev->idev);
if (err) {
dev_err(dev, "cannot register input device\n");
return err;
}
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int cros_ec_keyb_resume(struct device *dev)
{
struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
/*
* When the EC is not a wake source, then it could not have caused the
* resume, so we clear the EC's key scan buffer. If the EC was a
* wake source (e.g. the lid is open and the user might press a key to
* wake) then the key scan buffer should be preserved.
*/
if (ckdev->ec->was_wake_device)
cros_ec_keyb_clear_keyboard(ckdev);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
static struct platform_driver cros_ec_keyb_driver = {
.probe = cros_ec_keyb_probe,
.driver = {
.name = "cros-ec-keyb",
.pm = &cros_ec_keyb_pm_ops,
},
};
module_platform_driver(cros_ec_keyb_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
MODULE_ALIAS("platform:cros-ec-keyb");