/* SPDX-License-Identifier: GPL-2.0 */ /* * Helper code to detect 360 degree hinges (yoga) style 2-in-1 devices using 2 accelerometers * to allow the OS to determine the angle between the display and the base of the device. * * On Windows these are read by a special HingeAngleService process which calls undocumented * ACPI methods, to let the firmware know if the 2-in-1 is in tablet- or laptop-mode. * The firmware may use this to disable the kbd and touchpad to avoid spurious input in * tablet-mode as well as to report SW_TABLET_MODE info to the OS. * * Since Linux does not call these undocumented methods, the SW_TABLET_MODE info reported * by various drivers/platform/x86 drivers is incorrect. These drivers use the detection * code in this file to disable SW_TABLET_MODE reporting to avoid reporting broken info * (instead userspace can derive the status itself by directly reading the 2 accels). */ #include <linux/acpi.h> #include <linux/i2c.h> static bool dual_accel_detect_bosc0200(void) { struct acpi_device *adev; int count; adev = acpi_dev_get_first_match_dev("BOSC0200", NULL, -1); if (!adev) return false; count = i2c_acpi_client_count(adev); acpi_dev_put(adev); return count == 2; } static bool dual_accel_detect(void) { /* Systems which use a pair of accels with KIOX010A / KIOX020A ACPI ids */ if (acpi_dev_present("KIOX010A", NULL, -1) && acpi_dev_present("KIOX020A", NULL, -1)) return true; /* Systems which use a single DUAL250E ACPI device to model 2 accels */ if (acpi_dev_present("DUAL250E", NULL, -1)) return true; /* Systems which use a single BOSC0200 ACPI device to model 2 accels */ if (dual_accel_detect_bosc0200()) return true; return false; }