| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | /* |
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| 3 | * Helper code to detect 360 degree hinges (yoga) style 2-in-1 devices using 2 accelerometers |
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| 4 | * to allow the OS to determine the angle between the display and the base of the device. |
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| 5 | * |
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| 6 | * On Windows these are read by a special HingeAngleService process which calls undocumented |
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| 7 | * ACPI methods, to let the firmware know if the 2-in-1 is in tablet- or laptop-mode. |
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| 8 | * The firmware may use this to disable the kbd and touchpad to avoid spurious input in |
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| 9 | * tablet-mode as well as to report SW_TABLET_MODE info to the OS. |
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| 10 | * |
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| 11 | * Since Linux does not call these undocumented methods, the SW_TABLET_MODE info reported |
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| 12 | * by various drivers/platform/x86 drivers is incorrect. These drivers use the detection |
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| 13 | * code in this file to disable SW_TABLET_MODE reporting to avoid reporting broken info |
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| 14 | * (instead userspace can derive the status itself by directly reading the 2 accels). |
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| 15 | */ |
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| 16 | |
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| 17 | #include <linux/acpi.h> |
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| 18 | #include <linux/i2c.h> |
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| 19 | |
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| 20 | static bool dual_accel_detect_bosc0200(void) |
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| 21 | { |
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| 22 | struct acpi_device *adev; |
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| 23 | int count; |
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| 24 | |
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| 25 | adev = acpi_dev_get_first_match_dev(hid: "BOSC0200" , NULL, hrv: -1); |
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| 26 | if (!adev) |
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| 27 | return false; |
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| 28 | |
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| 29 | count = i2c_acpi_client_count(adev); |
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| 30 | |
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| 31 | acpi_dev_put(adev); |
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| 32 | |
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| 33 | return count == 2; |
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| 34 | } |
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| 35 | |
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| 36 | static bool dual_accel_detect(void) |
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| 37 | { |
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| 38 | /* Systems which use a pair of accels with KIOX010A / KIOX020A ACPI ids */ |
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| 39 | if (acpi_dev_present(hid: "KIOX010A" , NULL, hrv: -1) && |
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| 40 | acpi_dev_present(hid: "KIOX020A" , NULL, hrv: -1)) |
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| 41 | return true; |
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| 42 | |
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| 43 | /* Systems which use a single DUAL250E ACPI device to model 2 accels */ |
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| 44 | if (acpi_dev_present(hid: "DUAL250E" , NULL, hrv: -1)) |
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| 45 | return true; |
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| 46 | |
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| 47 | /* Systems which use a single BOSC0200 ACPI device to model 2 accels */ |
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| 48 | if (dual_accel_detect_bosc0200()) |
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| 49 | return true; |
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| 50 | |
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| 51 | return false; |
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| 52 | } |
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| 53 | |
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