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// SPDX-License-Identifier: GPL-2.0
// ChromeOS EC keyboard driver
//
// Copyright (C) 2012 Google, Inc.
//
// This driver uses the ChromeOS 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/bitops.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/notifier.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/sysrq.h>
#include <linux/input/matrix_keypad.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <asm/unaligned.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
* @valid_keys: bitmap of existing keys for each matrix column
* @old_kb_state: bitmap of keys pressed last scan
* @dev: Device pointer
* @ec: Top level ChromeOS device to use to talk to EC
* @idev: The input device for the matrix keys.
* @bs_idev: The input device for non-matrix buttons and switches (or NULL).
* @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;
uint8_t *valid_keys;
uint8_t *old_kb_state;
struct device *dev;
struct cros_ec_device *ec;
struct input_dev *idev;
struct input_dev *bs_idev;
struct notifier_block notifier;
};
/**
* cros_ec_bs_map - Struct mapping Linux keycodes to EC button/switch bitmap
* #defines
*
* @ev_type: The type of the input event to generate (e.g., EV_KEY).
* @code: A linux keycode
* @bit: A #define like EC_MKBP_POWER_BUTTON or EC_MKBP_LID_OPEN
* @inverted: If the #define and EV_SW have opposite meanings, this is true.
* Only applicable to switches.
*/
struct cros_ec_bs_map {
unsigned int ev_type;
unsigned int code;
u8 bit;
bool inverted;
};
/* cros_ec_keyb_bs - Map EC button/switch #defines into kernel ones */
static const struct cros_ec_bs_map cros_ec_keyb_bs[] = {
/* Buttons */
{
.ev_type = EV_KEY,
.code = KEY_POWER,
.bit = EC_MKBP_POWER_BUTTON,
},
{
.ev_type = EV_KEY,
.code = KEY_VOLUMEUP,
.bit = EC_MKBP_VOL_UP,
},
{
.ev_type = EV_KEY,
.code = KEY_VOLUMEDOWN,
.bit = EC_MKBP_VOL_DOWN,
},
/* Switches */
{
.ev_type = EV_SW,
.code = SW_LID,
.bit = EC_MKBP_LID_OPEN,
.inverted = true,
},
{
.ev_type = EV_SW,
.code = SW_TABLET_MODE,
.bit = EC_MKBP_TABLET_MODE,
},
};
/*
* 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 col1, col2, buf1, buf2;
struct device *dev = ckdev->dev;
uint8_t *valid_keys = ckdev->valid_keys;
/*
* 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).
*/
for (col1 = 0; col1 < ckdev->cols; col1++) {
buf1 = buf[col1] & valid_keys[col1];
for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
buf2 = buf[col2] & valid_keys[col2];
if (hweight8(buf1 & buf2) > 1) {
dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
col1, buf1, col2, buf2);
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 old_state;
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;
new_state = kb_state[col] & (1 << row);
old_state = ckdev->old_kb_state[col] & (1 << row);
if (new_state != old_state) {
dev_dbg(ckdev->dev,
"changed: [r%d c%d]: byte %02x\n",
row, col, new_state);
input_report_key(idev, keycodes[pos],
new_state);
}
}
ckdev->old_kb_state[col] = kb_state[col];
}
input_sync(ckdev->idev);
}
/**
* cros_ec_keyb_report_bs - Report non-matrixed buttons or switches
*
* This takes a bitmap of buttons or switches from the EC and reports events,
* syncing at the end.
*
* @ckdev: The keyboard device.
* @ev_type: The input event type (e.g., EV_KEY).
* @mask: A bitmap of buttons from the EC.
*/
static void cros_ec_keyb_report_bs(struct cros_ec_keyb *ckdev,
unsigned int ev_type, u32 mask)
{
struct input_dev *idev = ckdev->bs_idev;
int i;
for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
if (map->ev_type != ev_type)
continue;
input_event(idev, ev_type, map->code,
!!(mask & BIT(map->bit)) ^ map->inverted);
}
input_sync(idev);
}
static int cros_ec_keyb_work(struct notifier_block *nb,
unsigned long queued_during_suspend, void *_notify)
{
struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
notifier);
u32 val;
unsigned int ev_type;
/*
* If not wake enabled, discard key state changes during
* suspend. Switches will be re-checked in
* cros_ec_keyb_resume() to be sure nothing is lost.
*/
if (queued_during_suspend && !device_may_wakeup(ckdev->dev))
return NOTIFY_OK;
switch (ckdev->ec->event_data.event_type) {
case EC_MKBP_EVENT_KEY_MATRIX:
pm_wakeup_event(ckdev->dev, 0);
if (ckdev->ec->event_size != ckdev->cols) {
dev_err(ckdev->dev,
"Discarded incomplete key matrix event.\n");
return NOTIFY_OK;
}
cros_ec_keyb_process(ckdev,
ckdev->ec->event_data.data.key_matrix,
ckdev->ec->event_size);
break;
case EC_MKBP_EVENT_SYSRQ:
pm_wakeup_event(ckdev->dev, 0);
val = get_unaligned_le32(&ckdev->ec->event_data.data.sysrq);
dev_dbg(ckdev->dev, "sysrq code from EC: %#x\n", val);
handle_sysrq(val);
break;
case EC_MKBP_EVENT_BUTTON:
case EC_MKBP_EVENT_SWITCH:
pm_wakeup_event(ckdev->dev, 0);
if (ckdev->ec->event_data.event_type == EC_MKBP_EVENT_BUTTON) {
val = get_unaligned_le32(
&ckdev->ec->event_data.data.buttons);
ev_type = EV_KEY;
} else {
val = get_unaligned_le32(
&ckdev->ec->event_data.data.switches);
ev_type = EV_SW;
}
cros_ec_keyb_report_bs(ckdev, ev_type, val);
break;
default:
return NOTIFY_DONE;
}
return NOTIFY_OK;
}
/*
* Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW. Used by
* ghosting logic to ignore NULL or virtual keys.
*/
static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
{
int row, col;
int row_shift = ckdev->row_shift;
unsigned short *keymap = ckdev->idev->keycode;
unsigned short code;
BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));
for (col = 0; col < ckdev->cols; col++) {
for (row = 0; row < ckdev->rows; row++) {
code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
if (code && (code != KEY_BATTERY))
ckdev->valid_keys[col] |= 1 << row;
}
dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
col, ckdev->valid_keys[col]);
}
}
/**
* cros_ec_keyb_info - Wrap the EC command EC_CMD_MKBP_INFO
*
* This wraps the EC_CMD_MKBP_INFO, abstracting out all of the marshalling and
* unmarshalling and different version nonsense into something simple.
*
* @ec_dev: The EC device
* @info_type: Either EC_MKBP_INFO_SUPPORTED or EC_MKBP_INFO_CURRENT.
* @event_type: Either EC_MKBP_EVENT_BUTTON or EC_MKBP_EVENT_SWITCH. Actually
* in some cases this could be EC_MKBP_EVENT_KEY_MATRIX or
* EC_MKBP_EVENT_HOST_EVENT too but we don't use in this driver.
* @result: Where we'll store the result; a union
* @result_size: The size of the result. Expected to be the size of one of
* the elements in the union.
*
* Returns 0 if no error or -error upon error.
*/
static int cros_ec_keyb_info(struct cros_ec_device *ec_dev,
enum ec_mkbp_info_type info_type,
enum ec_mkbp_event event_type,
union ec_response_get_next_data *result,
size_t result_size)
{
struct ec_params_mkbp_info *params;
struct cros_ec_command *msg;
int ret;
msg = kzalloc(sizeof(*msg) + max_t(size_t, result_size,
sizeof(*params)), GFP_KERNEL);
if (!msg)
return -ENOMEM;
msg->command = EC_CMD_MKBP_INFO;
msg->version = 1;
msg->outsize = sizeof(*params);
msg->insize = result_size;
params = (struct ec_params_mkbp_info *)msg->data;
params->info_type = info_type;
params->event_type = event_type;
ret = cros_ec_cmd_xfer(ec_dev, msg);
if (ret < 0) {
dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n",
(int)info_type, (int)event_type, ret);
} else if (msg->result == EC_RES_INVALID_VERSION) {
/* With older ECs we just return 0 for everything */
memset(result, 0, result_size);
ret = 0;
} else if (msg->result != EC_RES_SUCCESS) {
dev_warn(ec_dev->dev, "Error getting info %d/%d: %d\n",
(int)info_type, (int)event_type, msg->result);
ret = -EPROTO;
} else if (ret != result_size) {
dev_warn(ec_dev->dev, "Wrong size %d/%d: %d != %zu\n",
(int)info_type, (int)event_type,
ret, result_size);
ret = -EPROTO;
} else {
memcpy(result, msg->data, result_size);
ret = 0;
}
kfree(msg);
return ret;
}
/**
* cros_ec_keyb_query_switches - Query the state of switches and report
*
* This will ask the EC about the current state of switches and report to the
* kernel. Note that we don't query for buttons because they are more
* transitory and we'll get an update on the next release / press.
*
* @ckdev: The keyboard device
*
* Returns 0 if no error or -error upon error.
*/
static int cros_ec_keyb_query_switches(struct cros_ec_keyb *ckdev)
{
struct cros_ec_device *ec_dev = ckdev->ec;
union ec_response_get_next_data event_data = {};
int ret;
ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_CURRENT,
EC_MKBP_EVENT_SWITCH, &event_data,
sizeof(event_data.switches));
if (ret)
return ret;
cros_ec_keyb_report_bs(ckdev, EV_SW,
get_unaligned_le32(&event_data.switches));
return 0;
}
/**
* cros_ec_keyb_resume - Resume the keyboard
*
* We use the resume notification as a chance to query the EC for switches.
*
* @dev: The keyboard device
*
* Returns 0 if no error or -error upon error.
*/
static __maybe_unused int cros_ec_keyb_resume(struct device *dev)
{
struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
if (ckdev->bs_idev)
return cros_ec_keyb_query_switches(ckdev);
return 0;
}
/**
* cros_ec_keyb_register_bs - Register non-matrix buttons/switches
*
* Handles all the bits of the keyboard driver related to non-matrix buttons
* and switches, including asking the EC about which are present and telling
* the kernel to expect them.
*
* If this device has no support for buttons and switches we'll return no error
* but the ckdev->bs_idev will remain NULL when this function exits.
*
* @ckdev: The keyboard device
*
* Returns 0 if no error or -error upon error.
*/
static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev)
{
struct cros_ec_device *ec_dev = ckdev->ec;
struct device *dev = ckdev->dev;
struct input_dev *idev;
union ec_response_get_next_data event_data = {};
const char *phys;
u32 buttons;
u32 switches;
int ret;
int i;
ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
EC_MKBP_EVENT_BUTTON, &event_data,
sizeof(event_data.buttons));
if (ret)
return ret;
buttons = get_unaligned_le32(&event_data.buttons);
ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
EC_MKBP_EVENT_SWITCH, &event_data,
sizeof(event_data.switches));
if (ret)
return ret;
switches = get_unaligned_le32(&event_data.switches);
if (!buttons && !switches)
return 0;
/*
* We call the non-matrix buttons/switches 'input1', if present.
* Allocate phys before input dev, to ensure correct tear-down
* ordering.
*/
phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input1", ec_dev->phys_name);
if (!phys)
return -ENOMEM;
idev = devm_input_allocate_device(dev);
if (!idev)
return -ENOMEM;
idev->name = "cros_ec_buttons";
idev->phys = phys;
__set_bit(EV_REP, idev->evbit);
idev->id.bustype = BUS_VIRTUAL;
idev->id.version = 1;
idev->id.product = 0;
idev->dev.parent = dev;
input_set_drvdata(idev, ckdev);
ckdev->bs_idev = idev;
for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
if ((map->ev_type == EV_KEY && (buttons & BIT(map->bit))) ||
(map->ev_type == EV_SW && (switches & BIT(map->bit))))
input_set_capability(idev, map->ev_type, map->code);
}
ret = cros_ec_keyb_query_switches(ckdev);
if (ret) {
dev_err(dev, "cannot query switches\n");
return ret;
}
ret = input_register_device(ckdev->bs_idev);
if (ret) {
dev_err(dev, "cannot register input device\n");
return ret;
}
return 0;
}
/**
* cros_ec_keyb_register_bs - Register matrix keys
*
* Handles all the bits of the keyboard driver related to matrix keys.
*
* @ckdev: The keyboard device
*
* Returns 0 if no error or -error upon error.
*/
static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
{
struct cros_ec_device *ec_dev = ckdev->ec;
struct device *dev = ckdev->dev;
struct input_dev *idev;
const char *phys;
int err;
err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
if (err)
return err;
ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
if (!ckdev->valid_keys)
return -ENOMEM;
ckdev->old_kb_state = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
if (!ckdev->old_kb_state)
return -ENOMEM;
/*
* We call the keyboard matrix 'input0'. Allocate phys before input
* dev, to ensure correct tear-down ordering.
*/
phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", ec_dev->phys_name);
if (!phys)
return -ENOMEM;
idev = devm_input_allocate_device(dev);
if (!idev)
return -ENOMEM;
idev->name = CROS_EC_DEV_NAME;
idev->phys = phys;
__set_bit(EV_REP, idev->evbit);
idev->id.bustype = BUS_VIRTUAL;
idev->id.version = 1;
idev->id.product = 0;
idev->dev.parent = dev;
ckdev->ghost_filter = of_property_read_bool(dev->of_node,
"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;
cros_ec_keyb_compute_valid_keys(ckdev);
err = input_register_device(ckdev->idev);
if (err) {
dev_err(dev, "cannot register input device\n");
return err;
}
return 0;
}
static int cros_ec_keyb_probe(struct platform_device *pdev)
{
struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
struct device *dev = &pdev->dev;
struct cros_ec_keyb *ckdev;
int err;
if (!dev->of_node)
return -ENODEV;
ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL);
if (!ckdev)
return -ENOMEM;
ckdev->ec = ec;
ckdev->dev = dev;
dev_set_drvdata(dev, ckdev);
err = cros_ec_keyb_register_matrix(ckdev);
if (err) {
dev_err(dev, "cannot register matrix inputs: %d\n", err);
return err;
}
err = cros_ec_keyb_register_bs(ckdev);
if (err) {
dev_err(dev, "cannot register non-matrix inputs: %d\n", err);
return err;
}
ckdev->notifier.notifier_call = cros_ec_keyb_work;
err = blocking_notifier_chain_register(&ckdev->ec->event_notifier,
&ckdev->notifier);
if (err) {
dev_err(dev, "cannot register notifier: %d\n", err);
return err;
}
device_init_wakeup(ckdev->dev, true);
return 0;
}
static int cros_ec_keyb_remove(struct platform_device *pdev)
{
struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev);
blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
&ckdev->notifier);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id cros_ec_keyb_of_match[] = {
{ .compatible = "google,cros-ec-keyb" },
{},
};
MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
#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,
.remove = cros_ec_keyb_remove,
.driver = {
.name = "cros-ec-keyb",
.of_match_table = of_match_ptr(cros_ec_keyb_of_match),
.pm = &cros_ec_keyb_pm_ops,
},
};
module_platform_driver(cros_ec_keyb_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
MODULE_ALIAS("platform:cros-ec-keyb");