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path: root/drivers/acpi/acpi_lpat.c
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Diffstat (limited to 'drivers/acpi/acpi_lpat.c')
-rw-r--r--drivers/acpi/acpi_lpat.c161
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_lpat.c b/drivers/acpi/acpi_lpat.c
new file mode 100644
index 000000000000..feb61c1630eb
--- /dev/null
+++ b/drivers/acpi/acpi_lpat.c
@@ -0,0 +1,161 @@
+/*
+ * acpi_lpat.c - LPAT table processing functions
+ *
+ * Copyright (C) 2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_lpat.h>
+
+/**
+ * acpi_lpat_raw_to_temp(): Return temperature from raw value through
+ * LPAT conversion table
+ *
+ * @lpat_table: the temperature_raw mapping table structure
+ * @raw: the raw value, used as a key to get the temerature from the
+ * above mapping table
+ *
+ * A positive converted temperarure value will be returned on success,
+ * a negative errno will be returned in error cases.
+ */
+int acpi_lpat_raw_to_temp(struct acpi_lpat_conversion_table *lpat_table,
+ int raw)
+{
+ int i, delta_temp, delta_raw, temp;
+ struct acpi_lpat *lpat = lpat_table->lpat;
+
+ for (i = 0; i < lpat_table->lpat_count - 1; i++) {
+ if ((raw >= lpat[i].raw && raw <= lpat[i+1].raw) ||
+ (raw <= lpat[i].raw && raw >= lpat[i+1].raw))
+ break;
+ }
+
+ if (i == lpat_table->lpat_count - 1)
+ return -ENOENT;
+
+ delta_temp = lpat[i+1].temp - lpat[i].temp;
+ delta_raw = lpat[i+1].raw - lpat[i].raw;
+ temp = lpat[i].temp + (raw - lpat[i].raw) * delta_temp / delta_raw;
+
+ return temp;
+}
+EXPORT_SYMBOL_GPL(acpi_lpat_raw_to_temp);
+
+/**
+ * acpi_lpat_temp_to_raw(): Return raw value from temperature through
+ * LPAT conversion table
+ *
+ * @lpat: the temperature_raw mapping table
+ * @temp: the temperature, used as a key to get the raw value from the
+ * above mapping table
+ *
+ * A positive converted temperature value will be returned on success,
+ * a negative errno will be returned in error cases.
+ */
+int acpi_lpat_temp_to_raw(struct acpi_lpat_conversion_table *lpat_table,
+ int temp)
+{
+ int i, delta_temp, delta_raw, raw;
+ struct acpi_lpat *lpat = lpat_table->lpat;
+
+ for (i = 0; i < lpat_table->lpat_count - 1; i++) {
+ if (temp >= lpat[i].temp && temp <= lpat[i+1].temp)
+ break;
+ }
+
+ if (i == lpat_table->lpat_count - 1)
+ return -ENOENT;
+
+ delta_temp = lpat[i+1].temp - lpat[i].temp;
+ delta_raw = lpat[i+1].raw - lpat[i].raw;
+ raw = lpat[i].raw + (temp - lpat[i].temp) * delta_raw / delta_temp;
+
+ return raw;
+}
+EXPORT_SYMBOL_GPL(acpi_lpat_temp_to_raw);
+
+/**
+ * acpi_lpat_get_conversion_table(): Parse ACPI LPAT table if present.
+ *
+ * @handle: Handle to acpi device
+ *
+ * Parse LPAT table to a struct of type acpi_lpat_table. On success
+ * it returns a pointer to newly allocated table. This table must
+ * be freed by the caller when finished processing, using a call to
+ * acpi_lpat_free_conversion_table.
+ */
+struct acpi_lpat_conversion_table *acpi_lpat_get_conversion_table(acpi_handle
+ handle)
+{
+ struct acpi_lpat_conversion_table *lpat_table = NULL;
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj_p, *obj_e;
+ int *lpat, i;
+ acpi_status status;
+
+ status = acpi_evaluate_object(handle, "LPAT", NULL, &buffer);
+ if (ACPI_FAILURE(status))
+ return NULL;
+
+ obj_p = (union acpi_object *)buffer.pointer;
+ if (!obj_p || (obj_p->type != ACPI_TYPE_PACKAGE) ||
+ (obj_p->package.count % 2) || (obj_p->package.count < 4))
+ goto out;
+
+ lpat = kcalloc(obj_p->package.count, sizeof(int), GFP_KERNEL);
+ if (!lpat)
+ goto out;
+
+ for (i = 0; i < obj_p->package.count; i++) {
+ obj_e = &obj_p->package.elements[i];
+ if (obj_e->type != ACPI_TYPE_INTEGER) {
+ kfree(lpat);
+ goto out;
+ }
+ lpat[i] = (s64)obj_e->integer.value;
+ }
+
+ lpat_table = kzalloc(sizeof(*lpat_table), GFP_KERNEL);
+ if (!lpat_table) {
+ kfree(lpat);
+ goto out;
+ }
+
+ lpat_table->lpat = (struct acpi_lpat *)lpat;
+ lpat_table->lpat_count = obj_p->package.count / 2;
+
+out:
+ kfree(buffer.pointer);
+ return lpat_table;
+}
+EXPORT_SYMBOL_GPL(acpi_lpat_get_conversion_table);
+
+/**
+ * acpi_lpat_free_conversion_table(): Free LPAT table.
+ *
+ * @lpat_table: the temperature_raw mapping table structure
+ *
+ * Frees the LPAT table previously allocated by a call to
+ * acpi_lpat_get_conversion_table.
+ */
+void acpi_lpat_free_conversion_table(struct acpi_lpat_conversion_table
+ *lpat_table)
+{
+ if (lpat_table) {
+ kfree(lpat_table->lpat);
+ kfree(lpat_table);
+ }
+}
+EXPORT_SYMBOL_GPL(acpi_lpat_free_conversion_table);
+
+MODULE_LICENSE("GPL");