[PATCH v2 1/2] ACPI / utils: Add acpi_evaluate_reg() helper

[Hans de Goede <hdegoede@redhat.com>]

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>
---
Changes in v2:
- Fix spelling error in commit message
- Add Andy's Suggested-by and Reviewed-by
---
 drivers/acpi/utils.c    | 25 +++++++++++++++++++++++++
 include/acpi/acpi_bus.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 804ac0df58ec..838b719ec7ce 100644
--- a/drivers/acpi/utils.c
+++ b/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
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index a92bea7184a8..5afb6ceb284f 100644
--- a/include/acpi/acpi_bus.h
+++ b/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);
-- 
2.26.0