122 lines · c
1// SPDX-License-Identifier: GPL-2.02// Driver to detect Tablet Mode for ChromeOS convertible.3//4// Copyright (C) 2017 Google, Inc.5// Author: Gwendal Grignou <gwendal@chromium.org>6//7// On Chromebook using ACPI, this device listens for notification8// from GOOG0006 and issue method TBMC to retrieve the status.9//10// GOOG0006 issues the notification when it receives EC_HOST_EVENT_MODE_CHANGE11// from the EC.12// Method TBMC reads EC_ACPI_MEM_DEVICE_ORIENTATION byte from the shared13// memory region.14 15#include <linux/acpi.h>16#include <linux/input.h>17#include <linux/io.h>18#include <linux/module.h>19#include <linux/printk.h>20 21#define DRV_NAME "chromeos_tbmc"22#define ACPI_DRV_NAME "GOOG0006"23 24static int chromeos_tbmc_query_switch(struct acpi_device *adev,25 struct input_dev *idev)26{27 unsigned long long state;28 acpi_status status;29 30 status = acpi_evaluate_integer(adev->handle, "TBMC", NULL, &state);31 if (ACPI_FAILURE(status))32 return -ENODEV;33 34 /* input layer checks if event is redundant */35 input_report_switch(idev, SW_TABLET_MODE, state);36 input_sync(idev);37 38 return 0;39}40 41static __maybe_unused int chromeos_tbmc_resume(struct device *dev)42{43 struct acpi_device *adev = to_acpi_device(dev);44 45 return chromeos_tbmc_query_switch(adev, adev->driver_data);46}47 48static void chromeos_tbmc_notify(struct acpi_device *adev, u32 event)49{50 acpi_pm_wakeup_event(&adev->dev);51 switch (event) {52 case 0x80:53 chromeos_tbmc_query_switch(adev, adev->driver_data);54 break;55 default:56 dev_err(&adev->dev, "Unexpected event: 0x%08X\n", event);57 }58}59 60static int chromeos_tbmc_open(struct input_dev *idev)61{62 struct acpi_device *adev = input_get_drvdata(idev);63 64 return chromeos_tbmc_query_switch(adev, idev);65}66 67static int chromeos_tbmc_add(struct acpi_device *adev)68{69 struct input_dev *idev;70 struct device *dev = &adev->dev;71 int ret;72 73 idev = devm_input_allocate_device(dev);74 if (!idev)75 return -ENOMEM;76 77 idev->name = "Tablet Mode Switch";78 idev->phys = acpi_device_hid(adev);79 80 idev->id.bustype = BUS_HOST;81 idev->id.version = 1;82 idev->id.product = 0;83 idev->open = chromeos_tbmc_open;84 85 input_set_drvdata(idev, adev);86 adev->driver_data = idev;87 88 input_set_capability(idev, EV_SW, SW_TABLET_MODE);89 ret = input_register_device(idev);90 if (ret) {91 dev_err(dev, "cannot register input device\n");92 return ret;93 }94 device_init_wakeup(dev, true);95 return 0;96}97 98static const struct acpi_device_id chromeos_tbmc_acpi_device_ids[] = {99 { ACPI_DRV_NAME, 0 },100 { }101};102MODULE_DEVICE_TABLE(acpi, chromeos_tbmc_acpi_device_ids);103 104static SIMPLE_DEV_PM_OPS(chromeos_tbmc_pm_ops, NULL,105 chromeos_tbmc_resume);106 107static struct acpi_driver chromeos_tbmc_driver = {108 .name = DRV_NAME,109 .class = DRV_NAME,110 .ids = chromeos_tbmc_acpi_device_ids,111 .ops = {112 .add = chromeos_tbmc_add,113 .notify = chromeos_tbmc_notify,114 },115 .drv.pm = &chromeos_tbmc_pm_ops,116};117 118module_acpi_driver(chromeos_tbmc_driver);119 120MODULE_LICENSE("GPL v2");121MODULE_DESCRIPTION("ChromeOS ACPI tablet switch driver");122