[PATCH v1 3/6] mfd: core: Propagate software node group to the sub devices

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

From: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

When ever device properties are supplied for a sub device, a software node
(fwnode) is actually created and then associated with that device. By allowing
the drivers to supply the complete software node group instead of just the
properties in it, the drivers can take advantage of the other features the
software nodes have on top of supplying the device properties.

Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 drivers/mfd/mfd-core.c   | 31 +++++++++++++++++++++++++++----
 include/linux/mfd/core.h |  3 +++
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index f5a73af60dd4..1a256f64dc9d 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -173,7 +173,24 @@ static int mfd_add_device(struct device *parent, int id,
 			goto fail_alias;
 	}
 
-	if (cell->properties) {
+	/* If software node group exists, use it, otherwise try properties */
+	if (cell->node_group) {
+		struct fwnode_handle *fwnode;
+
+		ret = software_node_register_node_group(cell->node_group);
+		if (ret)
+			goto fail_alias;
+
+		/*
+		 * The very first software node in the group is related to
+		 * the device itself. The rest can be device-less children to
+		 * fulfill the case of sub nodes (LEDs, GPIO keys, etc).
+		 */
+		fwnode = software_node_fwnode(cell->node_group[0]);
+
+		/* Assign this firmware node as a secondary one of the device */
+		set_secondary_fwnode(&pdev->dev, fwnode);
+	} else if (cell->properties) {
 		ret = platform_device_add_properties(pdev, cell->properties);
 		if (ret)
 			goto fail_alias;
@@ -213,18 +230,18 @@ static int mfd_add_device(struct device *parent, int id,
 			if (has_acpi_companion(&pdev->dev)) {
 				ret = acpi_check_resource_conflict(&res[r]);
 				if (ret)
-					goto fail_alias;
+					goto fail_resources;
 			}
 		}
 	}
 
 	ret = platform_device_add_resources(pdev, res, cell->num_resources);
 	if (ret)
-		goto fail_alias;
+		goto fail_resources;
 
 	ret = platform_device_add(pdev);
 	if (ret)
-		goto fail_alias;
+		goto fail_resources;
 
 	if (cell->pm_runtime_no_callbacks)
 		pm_runtime_no_callbacks(&pdev->dev);
@@ -233,6 +250,9 @@ static int mfd_add_device(struct device *parent, int id,
 
 	return 0;
 
+fail_resources:
+	set_secondary_fwnode(&pdev->dev, NULL);
+	software_node_unregister_node_group(cell->node_group);
 fail_alias:
 	regulator_bulk_unregister_supply_alias(&pdev->dev,
 					       cell->parent_supplies,
@@ -294,6 +314,9 @@ static int mfd_remove_devices_fn(struct device *dev, void *data)
 	pdev = to_platform_device(dev);
 	cell = mfd_get_cell(pdev);
 
+	set_secondary_fwnode(&pdev->dev, NULL);
+	software_node_unregister_node_group(cell->node_group);
+
 	regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies,
 					       cell->num_parent_supplies);
 
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index d01d1299e49d..9a998568759f 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -72,6 +72,9 @@ struct mfd_cell {
 	/* device properties passed to the sub devices drivers */
 	struct property_entry *properties;
 
+	/* Software node group for the sub device */
+	const struct software_node **node_group;
+
 	/*
 	 * Device Tree compatible string
 	 * See: Documentation/devicetree/usage-model.txt Chapter 2.2 for details
-- 
2.27.0.rc2