1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
// 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);
|
