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1// SPDX-License-Identifier: GPL-2.0-only2/* IIO ACPI helper functions */3 4#include <linux/acpi.h>5#include <linux/dev_printk.h>6#include <linux/iio/iio.h>7#include <linux/sprintf.h>8 9/**10 * iio_read_acpi_mount_matrix() - Read accelerometer mount matrix info from ACPI11 * @dev: Device structure12 * @orientation: iio_mount_matrix struct to fill13 * @acpi_method: ACPI method name to read the matrix from, usually "ROTM"14 *15 * Try to read the mount-matrix by calling the specified method on the device's16 * ACPI firmware-node. If the device has no ACPI firmware-node; or the method17 * does not exist then this will fail silently. This expects the method to18 * return data in the ACPI "ROTM" format defined by Microsoft:19 * https://learn.microsoft.com/en-us/windows-hardware/drivers/sensors/sensors-acpi-entries20 * This is a Microsoft extension and not part of the official ACPI spec.21 * The method name is configurable because some dual-accel setups define 2 mount22 * matrices in a single ACPI device using separate "ROMK" and "ROMS" methods.23 *24 * Returns: true if the matrix was successfully, false otherwise.25 */26bool iio_read_acpi_mount_matrix(struct device *dev,27 struct iio_mount_matrix *orientation,28 char *acpi_method)29{30 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };31 struct acpi_device *adev = ACPI_COMPANION(dev);32 char *str;33 union acpi_object *obj, *elements;34 acpi_status status;35 int i, j, val[3];36 bool ret = false;37 38 if (!adev || !acpi_has_method(adev->handle, acpi_method))39 return false;40 41 status = acpi_evaluate_object(adev->handle, acpi_method, NULL, &buffer);42 if (ACPI_FAILURE(status)) {43 dev_err(dev, "Failed to get ACPI mount matrix: %d\n", status);44 return false;45 }46 47 obj = buffer.pointer;48 if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 3) {49 dev_err(dev, "Unknown ACPI mount matrix package format\n");50 goto out_free_buffer;51 }52 53 elements = obj->package.elements;54 for (i = 0; i < 3; i++) {55 if (elements[i].type != ACPI_TYPE_STRING) {56 dev_err(dev, "Unknown ACPI mount matrix element format\n");57 goto out_free_buffer;58 }59 60 str = elements[i].string.pointer;61 if (sscanf(str, "%d %d %d", &val[0], &val[1], &val[2]) != 3) {62 dev_err(dev, "Incorrect ACPI mount matrix string format\n");63 goto out_free_buffer;64 }65 66 for (j = 0; j < 3; j++) {67 switch (val[j]) {68 case -1: str = "-1"; break;69 case 0: str = "0"; break;70 case 1: str = "1"; break;71 default:72 dev_err(dev, "Invalid value in ACPI mount matrix: %d\n", val[j]);73 goto out_free_buffer;74 }75 orientation->rotation[i * 3 + j] = str;76 }77 }78 79 ret = true;80 81out_free_buffer:82 kfree(buffer.pointer);83 return ret;84}85EXPORT_SYMBOL_GPL(iio_read_acpi_mount_matrix);86