86 lines
2.6 KiB
C
86 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/* IIO ACPI helper functions */
|
|
|
|
#include <linux/acpi.h>
|
|
#include <linux/dev_printk.h>
|
|
#include <linux/iio/iio.h>
|
|
#include <linux/sprintf.h>
|
|
|
|
/**
|
|
* iio_read_acpi_mount_matrix() - Read accelerometer mount matrix info from ACPI
|
|
* @dev: Device structure
|
|
* @orientation: iio_mount_matrix struct to fill
|
|
* @acpi_method: ACPI method name to read the matrix from, usually "ROTM"
|
|
*
|
|
* Try to read the mount-matrix by calling the specified method on the device's
|
|
* ACPI firmware-node. If the device has no ACPI firmware-node; or the method
|
|
* does not exist then this will fail silently. This expects the method to
|
|
* return data in the ACPI "ROTM" format defined by Microsoft:
|
|
* https://learn.microsoft.com/en-us/windows-hardware/drivers/sensors/sensors-acpi-entries
|
|
* This is a Microsoft extension and not part of the official ACPI spec.
|
|
* The method name is configurable because some dual-accel setups define 2 mount
|
|
* matrices in a single ACPI device using separate "ROMK" and "ROMS" methods.
|
|
*
|
|
* Returns: true if the matrix was successfully, false otherwise.
|
|
*/
|
|
bool iio_read_acpi_mount_matrix(struct device *dev,
|
|
struct iio_mount_matrix *orientation,
|
|
char *acpi_method)
|
|
{
|
|
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
|
|
struct acpi_device *adev = ACPI_COMPANION(dev);
|
|
char *str;
|
|
union acpi_object *obj, *elements;
|
|
acpi_status status;
|
|
int i, j, val[3];
|
|
bool ret = false;
|
|
|
|
if (!adev || !acpi_has_method(adev->handle, acpi_method))
|
|
return false;
|
|
|
|
status = acpi_evaluate_object(adev->handle, acpi_method, NULL, &buffer);
|
|
if (ACPI_FAILURE(status)) {
|
|
dev_err(dev, "Failed to get ACPI mount matrix: %d\n", status);
|
|
return false;
|
|
}
|
|
|
|
obj = buffer.pointer;
|
|
if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 3) {
|
|
dev_err(dev, "Unknown ACPI mount matrix package format\n");
|
|
goto out_free_buffer;
|
|
}
|
|
|
|
elements = obj->package.elements;
|
|
for (i = 0; i < 3; i++) {
|
|
if (elements[i].type != ACPI_TYPE_STRING) {
|
|
dev_err(dev, "Unknown ACPI mount matrix element format\n");
|
|
goto out_free_buffer;
|
|
}
|
|
|
|
str = elements[i].string.pointer;
|
|
if (sscanf(str, "%d %d %d", &val[0], &val[1], &val[2]) != 3) {
|
|
dev_err(dev, "Incorrect ACPI mount matrix string format\n");
|
|
goto out_free_buffer;
|
|
}
|
|
|
|
for (j = 0; j < 3; j++) {
|
|
switch (val[j]) {
|
|
case -1: str = "-1"; break;
|
|
case 0: str = "0"; break;
|
|
case 1: str = "1"; break;
|
|
default:
|
|
dev_err(dev, "Invalid value in ACPI mount matrix: %d\n", val[j]);
|
|
goto out_free_buffer;
|
|
}
|
|
orientation->rotation[i * 3 + j] = str;
|
|
}
|
|
}
|
|
|
|
ret = true;
|
|
|
|
out_free_buffer:
|
|
kfree(buffer.pointer);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iio_read_acpi_mount_matrix);
|