77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Helper code to detect 360 degree hinges (yoga) style 2-in-1 devices using 2 accelerometers
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* to allow the OS to determine the angle between the display and the base of the device.
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*
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* On Windows these are read by a special HingeAngleService process which calls undocumented
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* ACPI methods, to let the firmware know if the 2-in-1 is in tablet- or laptop-mode.
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* The firmware may use this to disable the kbd and touchpad to avoid spurious input in
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* tablet-mode as well as to report SW_TABLET_MODE info to the OS.
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*
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* Since Linux does not call these undocumented methods, the SW_TABLET_MODE info reported
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* by various drivers/platform/x86 drivers is incorrect. These drivers use the detection
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* code in this file to disable SW_TABLET_MODE reporting to avoid reporting broken info
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* (instead userspace can derive the status itself by directly reading the 2 accels).
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*/
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#include <linux/acpi.h>
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#include <linux/i2c.h>
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static int dual_accel_i2c_resource_count(struct acpi_resource *ares, void *data)
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{
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struct acpi_resource_i2c_serialbus *sb;
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int *count = data;
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if (i2c_acpi_get_i2c_resource(ares, &sb))
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*count = *count + 1;
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return 1;
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}
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static int dual_accel_i2c_client_count(struct acpi_device *adev)
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{
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int ret, count = 0;
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LIST_HEAD(r);
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ret = acpi_dev_get_resources(adev, &r, dual_accel_i2c_resource_count, &count);
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if (ret < 0)
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return ret;
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acpi_dev_free_resource_list(&r);
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return count;
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}
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static bool dual_accel_detect_bosc0200(void)
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{
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struct acpi_device *adev;
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int count;
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adev = acpi_dev_get_first_match_dev("BOSC0200", NULL, -1);
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if (!adev)
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return false;
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count = dual_accel_i2c_client_count(adev);
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acpi_dev_put(adev);
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return count == 2;
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}
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static bool dual_accel_detect(void)
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{
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/* Systems which use a pair of accels with KIOX010A / KIOX020A ACPI ids */
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if (acpi_dev_present("KIOX010A", NULL, -1) &&
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acpi_dev_present("KIOX020A", NULL, -1))
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return true;
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/* Systems which use a single DUAL250E ACPI device to model 2 accels */
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if (acpi_dev_present("DUAL250E", NULL, -1))
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return true;
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/* Systems which use a single BOSC0200 ACPI device to model 2 accels */
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if (dual_accel_detect_bosc0200())
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return true;
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return false;
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}
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