ACPI: utils: Add acpi_evaluate_reg() helper

With a recent fix to the pinctrl-cherryview driver we now have
2 drivers open-coding the parameter building / passing for calling
_REG on an ACPI handle.

Add a helper for this, so that these 2 drivers can be converted to this
helper.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/utils.c

@@ -605,6 +605,31 @@ acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
 	return status;
 }
 
+/**
+ * acpi_evaluate_reg: Evaluate _REG method to register OpRegion presence
+ * @handle: ACPI device handle
+ * @space_id: ACPI address space id to register OpRegion presence for
+ * @function: Parameter to pass to _REG one of ACPI_REG_CONNECT or
+ *            ACPI_REG_DISCONNECT
+ *
+ * Evaluate device's _REG method to register OpRegion presence.
+ */
+acpi_status acpi_evaluate_reg(acpi_handle handle, u8 space_id, u32 function)
+{
+	struct acpi_object_list arg_list;
+	union acpi_object params[2];
+
+	params[0].type = ACPI_TYPE_INTEGER;
+	params[0].integer.value = space_id;
+	params[1].type = ACPI_TYPE_INTEGER;
+	params[1].integer.value = function;
+	arg_list.count = 2;
+	arg_list.pointer = params;
+
+	return acpi_evaluate_object(handle, "_REG", &arg_list, NULL);
+}
+EXPORT_SYMBOL(acpi_evaluate_reg);
+
 /**
  * acpi_evaluate_dsm - evaluate device's _DSM method
  * @handle: ACPI device handle

include/acpi/acpi_bus.h

@@ -44,6 +44,7 @@ acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
 				       u64 arg);
 acpi_status acpi_evaluate_ej0(acpi_handle handle);
 acpi_status acpi_evaluate_lck(acpi_handle handle, int lock);
+acpi_status acpi_evaluate_reg(acpi_handle handle, u8 space_id, u32 function);
 bool acpi_ata_match(acpi_handle handle);
 bool acpi_bay_match(acpi_handle handle);
 bool acpi_dock_match(acpi_handle handle);