From b418f74170d7e066bad802e8563cabdb1b6032c6 Mon Sep 17 00:00:00 2001 From: Gwendal Grignou Date: Mon, 30 Jan 2017 15:47:22 -0800 Subject: [PATCH] platform: chrome: Add Tablet Switch ACPI driver Add a kernel driver for GOOG0006, an ACPI driver reporting an event when the tablet switch status changes. On an ACPI based convertible chromebook check evtest display tablet mode switch changes: Available devices: .. /dev/input/event3: Tablet Mode Switch .. Testing ... (interrupt to exit) Event: time 1484879712.604360, type 5 (EV_SW), code 1 (SW_TABLET_MODE), value 1 Event: time 1484879712.604360, -------------- SYN_REPORT ------------ Event: time 1484879715.132228, type 5 (EV_SW), code 1 (SW_TABLET_MODE), value 0 Event: time 1484879715.132228, -------------- SYN_REPORT ------------ ... Check state is updated at resume time when different from suspend time. Signed-off-by: Gwendal Grignou Signed-off-by: Benson Leung --- drivers/platform/chrome/Kconfig | 10 +++ drivers/platform/chrome/Makefile | 1 + drivers/platform/chrome/chromeos_tbmc.c | 128 ++++++++++++++++++++++++++++++++ 3 files changed, 139 insertions(+) create mode 100644 drivers/platform/chrome/chromeos_tbmc.c diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index e728a96..57aabe6 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -38,6 +38,16 @@ config CHROMEOS_PSTORE If you have a supported Chromebook, choose Y or M here. The module will be called chromeos_pstore. +config CHROMEOS_TBMC + tristate "ChromeOS Tablet Switch Controller" + depends on ACPI + help + This option adds a driver for the tablet switch on + select Chrome OS systems. + + To compile this driver as a module, choose M here: the + module will be called chromeos_tbmc. + config CROS_EC_CTL tristate diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index ff3b369..e44c37a 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -2,6 +2,7 @@ obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o +obj-$(CONFIG_CHROMEOS_TBMC) += chromeos_tbmc.o cros_ec_ctl-objs := cros_ec_sysfs.o cros_ec_lightbar.o \ cros_ec_vbc.o cros_ec_debugfs.o obj-$(CONFIG_CROS_EC_CTL) += cros_ec_ctl.o diff --git a/drivers/platform/chrome/chromeos_tbmc.c b/drivers/platform/chrome/chromeos_tbmc.c new file mode 100644 index 0000000..c87e533 --- /dev/null +++ b/drivers/platform/chrome/chromeos_tbmc.c @@ -0,0 +1,128 @@ +/* + * chromeos_tbmc - Driver to detect Tablet Mode for ChromeOS convertible. + * + * Copyright 2017 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. + * + * On Chromebook using ACPI, this device listens for notification + * from GOOG0006 and issue method TBMC to retrieve the status. + * + * GOOG0006 issues the notification when it receives EC_HOST_EVENT_MODE_CHANGE + * from the EC. + * Method TBMC reads EC_ACPI_MEM_DEVICE_ORIENTATION byte from the shared + * memory region. + */ + +#include +#include +#include +#include +#include + +#define DRV_NAME "chromeos_tbmc" +#define ACPI_DRV_NAME "GOOG0006" + +static int chromeos_tbmc_query_switch(struct acpi_device *adev, + struct input_dev *idev) +{ + unsigned long long state; + acpi_status status; + + status = acpi_evaluate_integer(adev->handle, "TBMC", NULL, &state); + if (ACPI_FAILURE(status)) + return -ENODEV; + + /* input layer checks if event is redundant */ + input_report_switch(idev, SW_TABLET_MODE, state); + input_sync(idev); + + return 0; +} + +static __maybe_unused int chromeos_tbmc_resume(struct device *dev) +{ + struct acpi_device *adev = to_acpi_device(dev); + + return chromeos_tbmc_query_switch(adev, adev->driver_data); +} + +static void chromeos_tbmc_notify(struct acpi_device *adev, u32 event) +{ + switch (event) { + case 0x80: + chromeos_tbmc_query_switch(adev, adev->driver_data); + break; + default: + dev_err(&adev->dev, "Unexpected event: 0x%08X\n", event); + } +} + +static int chromeos_tbmc_open(struct input_dev *idev) +{ + struct acpi_device *adev = input_get_drvdata(idev); + + return chromeos_tbmc_query_switch(adev, idev); +} + +static int chromeos_tbmc_add(struct acpi_device *adev) +{ + struct input_dev *idev; + struct device *dev = &adev->dev; + int ret; + + idev = devm_input_allocate_device(dev); + if (!idev) + return -ENOMEM; + + idev->name = "Tablet Mode Switch"; + idev->phys = acpi_device_hid(adev); + + idev->id.bustype = BUS_HOST; + idev->id.version = 1; + idev->id.product = 0; + idev->open = chromeos_tbmc_open; + + input_set_drvdata(idev, adev); + adev->driver_data = idev; + + input_set_capability(idev, EV_SW, SW_TABLET_MODE); + ret = input_register_device(idev); + if (ret) { + dev_err(dev, "cannot register input device\n"); + return ret; + } + return 0; +} + +static const struct acpi_device_id chromeos_tbmc_acpi_device_ids[] = { + { ACPI_DRV_NAME, 0 }, + { } +}; +MODULE_DEVICE_TABLE(acpi, chromeos_tbmc_acpi_device_ids); + +static const SIMPLE_DEV_PM_OPS(chromeos_tbmc_pm_ops, NULL, + chromeos_tbmc_resume); + +static struct acpi_driver chromeos_tbmc_driver = { + .name = DRV_NAME, + .class = DRV_NAME, + .ids = chromeos_tbmc_acpi_device_ids, + .ops = { + .add = chromeos_tbmc_add, + .notify = chromeos_tbmc_notify, + }, + .drv.pm = &chromeos_tbmc_pm_ops, +}; + +module_acpi_driver(chromeos_tbmc_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("ChromeOS ACPI tablet switch driver"); -- 2.7.4