linux/drivers/hid/hid-google-hammer.c
Nicolas Boichat df7b622906 HID: google: Get HID report on probe to confirm tablet switch state
This forces reading the base folded state anytime the device is
probed, to make sure it's in sync.

This is useful after a reboot, if the device re-enumerates for
any reason (e.g. ESD shock), or if the driver is unbound/rebound
(debugging/testing).

Without this, the tablet switch state is only synchronized after a
key is pressed (since the device would then send a report that
includes the switch state), leading to strange UX (e.g. UI
mode changes when a key is pressed after reboot).

This is not a problem on detachable base attach, as the device,
by itself, sends a report after it is booted up.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2021-02-02 11:30:23 +01:00

629 lines
15 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* HID driver for Google Hammer device.
*
* Copyright (c) 2017 Google Inc.
* Author: Wei-Ning Huang <wnhuang@google.com>
*/
/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*/
#include <linux/acpi.h>
#include <linux/hid.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeup.h>
#include <asm/unaligned.h>
#include "hid-ids.h"
/*
* C(hrome)B(ase)A(ttached)S(witch) - switch exported by Chrome EC and reporting
* state of the "Whiskers" base - attached or detached. Whiskers USB device also
* reports position of the keyboard - folded or not. Combining base state and
* position allows us to generate proper "Tablet mode" events.
*/
struct cbas_ec {
struct device *dev; /* The platform device (EC) */
struct input_dev *input;
bool base_present;
bool base_folded;
struct notifier_block notifier;
};
static struct cbas_ec cbas_ec;
static DEFINE_SPINLOCK(cbas_ec_lock);
static DEFINE_MUTEX(cbas_ec_reglock);
static bool cbas_parse_base_state(const void *data)
{
u32 switches = get_unaligned_le32(data);
return !!(switches & BIT(EC_MKBP_BASE_ATTACHED));
}
static int cbas_ec_query_base(struct cros_ec_device *ec_dev, bool get_state,
bool *state)
{
struct ec_params_mkbp_info *params;
struct cros_ec_command *msg;
int ret;
msg = kzalloc(sizeof(*msg) + max(sizeof(u32), sizeof(*params)),
GFP_KERNEL);
if (!msg)
return -ENOMEM;
msg->command = EC_CMD_MKBP_INFO;
msg->version = 1;
msg->outsize = sizeof(*params);
msg->insize = sizeof(u32);
params = (struct ec_params_mkbp_info *)msg->data;
params->info_type = get_state ?
EC_MKBP_INFO_CURRENT : EC_MKBP_INFO_SUPPORTED;
params->event_type = EC_MKBP_EVENT_SWITCH;
ret = cros_ec_cmd_xfer_status(ec_dev, msg);
if (ret >= 0) {
if (ret != sizeof(u32)) {
dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n",
ret, sizeof(u32));
ret = -EPROTO;
} else {
*state = cbas_parse_base_state(msg->data);
ret = 0;
}
}
kfree(msg);
return ret;
}
static int cbas_ec_notify(struct notifier_block *nb,
unsigned long queued_during_suspend,
void *_notify)
{
struct cros_ec_device *ec = _notify;
unsigned long flags;
bool base_present;
if (ec->event_data.event_type == EC_MKBP_EVENT_SWITCH) {
base_present = cbas_parse_base_state(
&ec->event_data.data.switches);
dev_dbg(cbas_ec.dev,
"%s: base: %d\n", __func__, base_present);
if (device_may_wakeup(cbas_ec.dev) ||
!queued_during_suspend) {
pm_wakeup_event(cbas_ec.dev, 0);
spin_lock_irqsave(&cbas_ec_lock, flags);
/*
* While input layer dedupes the events, we do not want
* to disrupt the state reported by the base by
* overriding it with state reported by the LID. Only
* report changes, as we assume that on attach the base
* is not folded.
*/
if (base_present != cbas_ec.base_present) {
input_report_switch(cbas_ec.input,
SW_TABLET_MODE,
!base_present);
input_sync(cbas_ec.input);
cbas_ec.base_present = base_present;
}
spin_unlock_irqrestore(&cbas_ec_lock, flags);
}
}
return NOTIFY_OK;
}
static __maybe_unused int cbas_ec_resume(struct device *dev)
{
struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
bool base_present;
int error;
error = cbas_ec_query_base(ec, true, &base_present);
if (error) {
dev_warn(dev, "failed to fetch base state on resume: %d\n",
error);
} else {
spin_lock_irq(&cbas_ec_lock);
cbas_ec.base_present = base_present;
/*
* Only report if base is disconnected. If base is connected,
* it will resend its state on resume, and we'll update it
* in hammer_event().
*/
if (!cbas_ec.base_present) {
input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
input_sync(cbas_ec.input);
}
spin_unlock_irq(&cbas_ec_lock);
}
return 0;
}
static SIMPLE_DEV_PM_OPS(cbas_ec_pm_ops, NULL, cbas_ec_resume);
static void cbas_ec_set_input(struct input_dev *input)
{
/* Take the lock so hammer_event() does not race with us here */
spin_lock_irq(&cbas_ec_lock);
cbas_ec.input = input;
spin_unlock_irq(&cbas_ec_lock);
}
static int __cbas_ec_probe(struct platform_device *pdev)
{
struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
struct input_dev *input;
bool base_supported;
int error;
error = cbas_ec_query_base(ec, false, &base_supported);
if (error)
return error;
if (!base_supported)
return -ENXIO;
input = devm_input_allocate_device(&pdev->dev);
if (!input)
return -ENOMEM;
input->name = "Whiskers Tablet Mode Switch";
input->id.bustype = BUS_HOST;
input_set_capability(input, EV_SW, SW_TABLET_MODE);
error = input_register_device(input);
if (error) {
dev_err(&pdev->dev, "cannot register input device: %d\n",
error);
return error;
}
/* Seed the state */
error = cbas_ec_query_base(ec, true, &cbas_ec.base_present);
if (error) {
dev_err(&pdev->dev, "cannot query base state: %d\n", error);
return error;
}
if (!cbas_ec.base_present)
cbas_ec.base_folded = false;
dev_dbg(&pdev->dev, "%s: base: %d, folded: %d\n", __func__,
cbas_ec.base_present, cbas_ec.base_folded);
input_report_switch(input, SW_TABLET_MODE,
!cbas_ec.base_present || cbas_ec.base_folded);
cbas_ec_set_input(input);
cbas_ec.dev = &pdev->dev;
cbas_ec.notifier.notifier_call = cbas_ec_notify;
error = blocking_notifier_chain_register(&ec->event_notifier,
&cbas_ec.notifier);
if (error) {
dev_err(&pdev->dev, "cannot register notifier: %d\n", error);
cbas_ec_set_input(NULL);
return error;
}
device_init_wakeup(&pdev->dev, true);
return 0;
}
static int cbas_ec_probe(struct platform_device *pdev)
{
int retval;
mutex_lock(&cbas_ec_reglock);
if (cbas_ec.input) {
retval = -EBUSY;
goto out;
}
retval = __cbas_ec_probe(pdev);
out:
mutex_unlock(&cbas_ec_reglock);
return retval;
}
static int cbas_ec_remove(struct platform_device *pdev)
{
struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
mutex_lock(&cbas_ec_reglock);
blocking_notifier_chain_unregister(&ec->event_notifier,
&cbas_ec.notifier);
cbas_ec_set_input(NULL);
mutex_unlock(&cbas_ec_reglock);
return 0;
}
static const struct acpi_device_id cbas_ec_acpi_ids[] = {
{ "GOOG000B", 0 },
{ }
};
MODULE_DEVICE_TABLE(acpi, cbas_ec_acpi_ids);
static struct platform_driver cbas_ec_driver = {
.probe = cbas_ec_probe,
.remove = cbas_ec_remove,
.driver = {
.name = "cbas_ec",
.acpi_match_table = ACPI_PTR(cbas_ec_acpi_ids),
.pm = &cbas_ec_pm_ops,
},
};
#define MAX_BRIGHTNESS 100
struct hammer_kbd_leds {
struct led_classdev cdev;
struct hid_device *hdev;
u8 buf[2] ____cacheline_aligned;
};
static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
enum led_brightness br)
{
struct hammer_kbd_leds *led = container_of(cdev,
struct hammer_kbd_leds,
cdev);
int ret;
led->buf[0] = 0;
led->buf[1] = br;
/*
* Request USB HID device to be in Full On mode, so that sending
* hardware output report and hardware raw request won't fail.
*/
ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
if (ret < 0) {
hid_err(led->hdev, "failed: device not resumed %d\n", ret);
return ret;
}
ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
if (ret == -ENOSYS)
ret = hid_hw_raw_request(led->hdev, 0, led->buf,
sizeof(led->buf),
HID_OUTPUT_REPORT,
HID_REQ_SET_REPORT);
if (ret < 0)
hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
ret);
/* Request USB HID device back to Normal Mode. */
hid_hw_power(led->hdev, PM_HINT_NORMAL);
return ret;
}
static int hammer_register_leds(struct hid_device *hdev)
{
struct hammer_kbd_leds *kbd_backlight;
int error;
kbd_backlight = kzalloc(sizeof(*kbd_backlight), GFP_KERNEL);
if (!kbd_backlight)
return -ENOMEM;
kbd_backlight->hdev = hdev;
kbd_backlight->cdev.name = "hammer::kbd_backlight";
kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
kbd_backlight->cdev.brightness_set_blocking =
hammer_kbd_brightness_set_blocking;
kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
/* Set backlight to 0% initially. */
hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
error = led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
if (error)
goto err_free_mem;
hid_set_drvdata(hdev, kbd_backlight);
return 0;
err_free_mem:
kfree(kbd_backlight);
return error;
}
static void hammer_unregister_leds(struct hid_device *hdev)
{
struct hammer_kbd_leds *kbd_backlight = hid_get_drvdata(hdev);
if (kbd_backlight) {
led_classdev_unregister(&kbd_backlight->cdev);
kfree(kbd_backlight);
}
}
#define HID_UP_GOOGLEVENDOR 0xffd10000
#define HID_VD_KBD_FOLDED 0x00000019
#define HID_USAGE_KBD_FOLDED (HID_UP_GOOGLEVENDOR | HID_VD_KBD_FOLDED)
/* HID usage for keyboard backlight (Alphanumeric display brightness) */
#define HID_AD_BRIGHTNESS 0x00140046
static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
struct hid_field *field,
struct hid_usage *usage,
unsigned long **bit, int *max)
{
if (usage->hid == HID_USAGE_KBD_FOLDED) {
/*
* We do not want to have this usage mapped as it will get
* mixed in with "base attached" signal and delivered over
* separate input device for tablet switch mode.
*/
return -1;
}
return 0;
}
static void hammer_folded_event(struct hid_device *hdev, bool folded)
{
unsigned long flags;
spin_lock_irqsave(&cbas_ec_lock, flags);
/*
* If we are getting events from Whiskers that means that it
* is attached to the lid.
*/
cbas_ec.base_present = true;
cbas_ec.base_folded = folded;
hid_dbg(hdev, "%s: base: %d, folded: %d\n", __func__,
cbas_ec.base_present, cbas_ec.base_folded);
if (cbas_ec.input) {
input_report_switch(cbas_ec.input, SW_TABLET_MODE, folded);
input_sync(cbas_ec.input);
}
spin_unlock_irqrestore(&cbas_ec_lock, flags);
}
static int hammer_event(struct hid_device *hid, struct hid_field *field,
struct hid_usage *usage, __s32 value)
{
if (usage->hid == HID_USAGE_KBD_FOLDED) {
hammer_folded_event(hid, value);
return 1; /* We handled this event */
}
return 0;
}
static bool hammer_has_usage(struct hid_device *hdev, unsigned int report_type,
unsigned application, unsigned usage)
{
struct hid_report_enum *re = &hdev->report_enum[report_type];
struct hid_report *report;
int i, j;
list_for_each_entry(report, &re->report_list, list) {
if (report->application != application)
continue;
for (i = 0; i < report->maxfield; i++) {
struct hid_field *field = report->field[i];
for (j = 0; j < field->maxusage; j++)
if (field->usage[j].hid == usage)
return true;
}
}
return false;
}
static bool hammer_has_folded_event(struct hid_device *hdev)
{
return hammer_has_usage(hdev, HID_INPUT_REPORT,
HID_GD_KEYBOARD, HID_USAGE_KBD_FOLDED);
}
static bool hammer_has_backlight_control(struct hid_device *hdev)
{
return hammer_has_usage(hdev, HID_OUTPUT_REPORT,
HID_GD_KEYBOARD, HID_AD_BRIGHTNESS);
}
static void hammer_get_folded_state(struct hid_device *hdev)
{
struct hid_report *report;
char *buf;
int len, rlen;
int a;
report = hdev->report_enum[HID_INPUT_REPORT].report_id_hash[0x0];
if (!report || report->maxfield < 1)
return;
len = hid_report_len(report) + 1;
buf = kmalloc(len, GFP_KERNEL);
if (!buf)
return;
rlen = hid_hw_raw_request(hdev, report->id, buf, len, report->type, HID_REQ_GET_REPORT);
if (rlen != len) {
hid_warn(hdev, "Unable to read base folded state: %d (expected %d)\n", rlen, len);
goto out;
}
for (a = 0; a < report->maxfield; a++) {
struct hid_field *field = report->field[a];
if (field->usage->hid == HID_USAGE_KBD_FOLDED) {
u32 value = hid_field_extract(hdev, buf+1,
field->report_offset, field->report_size);
hammer_folded_event(hdev, value);
break;
}
}
out:
kfree(buf);
}
static int hammer_probe(struct hid_device *hdev,
const struct hid_device_id *id)
{
int error;
error = hid_parse(hdev);
if (error)
return error;
error = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
if (error)
return error;
/*
* We always want to poll for, and handle tablet mode events from
* devices that have folded usage, even when nobody has opened the input
* device. This also prevents the hid core from dropping early tablet
* mode events from the device.
*/
if (hammer_has_folded_event(hdev)) {
hdev->quirks |= HID_QUIRK_ALWAYS_POLL;
error = hid_hw_open(hdev);
if (error)
return error;
hammer_get_folded_state(hdev);
}
if (hammer_has_backlight_control(hdev)) {
error = hammer_register_leds(hdev);
if (error)
hid_warn(hdev,
"Failed to register keyboard backlight: %d\n",
error);
}
return 0;
}
static void hammer_remove(struct hid_device *hdev)
{
unsigned long flags;
if (hammer_has_folded_event(hdev)) {
hid_hw_close(hdev);
/*
* If we are disconnecting then most likely Whiskers is
* being removed. Even if it is not removed, without proper
* keyboard we should not stay in clamshell mode.
*
* The reason for doing it here and not waiting for signal
* from EC, is that on some devices there are high leakage
* on Whiskers pins and we do not detect disconnect reliably,
* resulting in devices being stuck in clamshell mode.
*/
spin_lock_irqsave(&cbas_ec_lock, flags);
if (cbas_ec.input && cbas_ec.base_present) {
input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
input_sync(cbas_ec.input);
}
cbas_ec.base_present = false;
spin_unlock_irqrestore(&cbas_ec_lock, flags);
}
hammer_unregister_leds(hdev);
hid_hw_stop(hdev);
}
static const struct hid_device_id hammer_devices[] = {
{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MAGNEMITE) },
{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MASTERBALL) },
{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MOONBALL) },
{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
{ }
};
MODULE_DEVICE_TABLE(hid, hammer_devices);
static struct hid_driver hammer_driver = {
.name = "hammer",
.id_table = hammer_devices,
.probe = hammer_probe,
.remove = hammer_remove,
.input_mapping = hammer_input_mapping,
.event = hammer_event,
};
static int __init hammer_init(void)
{
int error;
error = platform_driver_register(&cbas_ec_driver);
if (error)
return error;
error = hid_register_driver(&hammer_driver);
if (error) {
platform_driver_unregister(&cbas_ec_driver);
return error;
}
return 0;
}
module_init(hammer_init);
static void __exit hammer_exit(void)
{
hid_unregister_driver(&hammer_driver);
platform_driver_unregister(&cbas_ec_driver);
}
module_exit(hammer_exit);
MODULE_LICENSE("GPL");