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In all cases in which a struct acpi_driver is used for binding a driver to an ACPI device object, a corresponding platform device is created by the ACPI core and that device is regarded as a proper representation of underlying hardware. Accordingly, a struct platform_driver should be used by driver code to bind to that device. There are multiple reasons why drivers should not bind directly to ACPI device objects [1]. Overall, it is better to bind drivers to platform devices than to their ACPI companions, so convert the ChromeOS tablet mode change (TBMC) ACPI driver to a platform one. After this change, the subordinate input device and wakeup source class device will be registered under the platform device used for driver binding instead of its ACPI companion. While this is not expected to alter functionality, it changes sysfs layout and so it will be visible to user space. Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/ [1] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/10827297.nUPlyArG6x@rafael.j.wysocki Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
139 lines
3.5 KiB
C
139 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Driver to detect Tablet Mode for ChromeOS convertible.
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//
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// Copyright (C) 2017 Google, Inc.
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// Author: Gwendal Grignou <gwendal@chromium.org>
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//
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// On Chromebook using ACPI, this device listens for notification
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// from GOOG0006 and issue method TBMC to retrieve the status.
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//
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// GOOG0006 issues the notification when it receives EC_HOST_EVENT_MODE_CHANGE
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// from the EC.
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// Method TBMC reads EC_ACPI_MEM_DEVICE_ORIENTATION byte from the shared
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// memory region.
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#include <linux/acpi.h>
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#include <linux/input.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/printk.h>
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#define DRV_NAME "chromeos_tbmc"
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#define ACPI_DRV_NAME "GOOG0006"
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static int chromeos_tbmc_query_switch(struct acpi_device *adev,
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struct input_dev *idev)
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{
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unsigned long long state;
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acpi_status status;
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status = acpi_evaluate_integer(adev->handle, "TBMC", NULL, &state);
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if (ACPI_FAILURE(status))
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return -ENODEV;
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/* input layer checks if event is redundant */
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input_report_switch(idev, SW_TABLET_MODE, state);
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input_sync(idev);
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return 0;
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}
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static __maybe_unused int chromeos_tbmc_resume(struct device *dev)
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{
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return chromeos_tbmc_query_switch(ACPI_COMPANION(dev), dev_get_drvdata(dev));
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}
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static void chromeos_tbmc_notify(acpi_handle handle, u32 event, void *data)
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{
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struct device *dev = data;
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acpi_pm_wakeup_event(dev);
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switch (event) {
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case 0x80:
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chromeos_tbmc_query_switch(ACPI_COMPANION(dev), dev_get_drvdata(dev));
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break;
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default:
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dev_err(dev, "Unexpected event: 0x%08X\n", event);
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}
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}
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static int chromeos_tbmc_open(struct input_dev *idev)
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{
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struct acpi_device *adev = input_get_drvdata(idev);
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return chromeos_tbmc_query_switch(adev, idev);
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}
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static int chromeos_tbmc_probe(struct platform_device *pdev)
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{
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struct input_dev *idev;
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struct device *dev = &pdev->dev;
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struct acpi_device *adev = ACPI_COMPANION(dev);
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int ret;
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idev = devm_input_allocate_device(dev);
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if (!idev)
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return -ENOMEM;
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idev->name = "Tablet Mode Switch";
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idev->phys = acpi_device_hid(adev);
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idev->id.bustype = BUS_HOST;
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idev->id.version = 1;
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idev->id.product = 0;
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idev->open = chromeos_tbmc_open;
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input_set_drvdata(idev, adev);
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platform_set_drvdata(pdev, idev);
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input_set_capability(idev, EV_SW, SW_TABLET_MODE);
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ret = input_register_device(idev);
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if (ret) {
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dev_err(dev, "cannot register input device\n");
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return ret;
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}
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device_init_wakeup(dev, true);
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ret = acpi_dev_install_notify_handler(adev, ACPI_DEVICE_NOTIFY,
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chromeos_tbmc_notify, dev);
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if (ret) {
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dev_err(dev, "cannot install ACPI notify handler\n");
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device_init_wakeup(dev, false);
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return ret;
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}
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return 0;
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}
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static void chromeos_tbmc_remove(struct platform_device *pdev)
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{
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acpi_dev_remove_notify_handler(ACPI_COMPANION(&pdev->dev),
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ACPI_DEVICE_NOTIFY, chromeos_tbmc_notify);
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device_init_wakeup(&pdev->dev, false);
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}
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static const struct acpi_device_id chromeos_tbmc_acpi_device_ids[] = {
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{ ACPI_DRV_NAME, 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, chromeos_tbmc_acpi_device_ids);
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static SIMPLE_DEV_PM_OPS(chromeos_tbmc_pm_ops, NULL,
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chromeos_tbmc_resume);
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static struct platform_driver chromeos_tbmc_driver = {
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.probe = chromeos_tbmc_probe,
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.remove = chromeos_tbmc_remove,
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.driver = {
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.name = DRV_NAME,
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.acpi_match_table = chromeos_tbmc_acpi_device_ids,
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.pm = &chromeos_tbmc_pm_ops,
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},
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};
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module_platform_driver(chromeos_tbmc_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("ChromeOS ACPI tablet switch driver");
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