linux-kernel - [PATCH 1/2] mfd: core: Support multiple OF child devices of the same type

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Message-Id: <1559687743-31879-2-git-send-email-hancock@sedsystems.ca>
Date:   Tue,  4 Jun 2019 16:35:42 -0600
From:   Robert Hancock <hancock@...systems.ca>
To:     linux-kernel@...r.kernel.org
Cc:     lee.jones@...aro.org, Robert Hancock <hancock@...systems.ca>
Subject: [PATCH 1/2] mfd: core: Support multiple OF child devices of the same type

Previously the MFD core supported assigning OF nodes to created MFD
devices, but relied solely on matching the of_compatible string. This
would result in devices being potentially assigned the wrong node if
there are multiple devices with the same compatible string within a
multifunction device.

Add support for matching the full name of the node in the MFD cell
definition, so that we can match against a specific instance of a
device. If this is not specified, we match just based on the
compatible string, as before.

Signed-off-by: Robert Hancock <hancock@...systems.ca>
---
 drivers/mfd/mfd-core.c   | 5 ++++-
 include/linux/mfd/core.h | 3 +++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 1ade4c8..74bc895 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -177,7 +177,10 @@ static int mfd_add_device(struct device *parent, int id,
 
 	if (parent->of_node && cell->of_compatible) {
 		for_each_child_of_node(parent->of_node, np) {
-			if (of_device_is_compatible(np, cell->of_compatible)) {
+			if (of_device_is_compatible(np, cell->of_compatible) &&
+			    (!cell->of_full_name ||
+			     !strcmp(cell->of_full_name,
+				     of_node_full_name(np)))) {
 				pdev->dev.of_node = np;
 				break;
 			}
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index 99c0395..470f6cb 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -55,6 +55,9 @@ struct mfd_cell {
 	 */
 	const char		*of_compatible;
 
+	/* Optionally match against a specific device of a given type */
+	const char		*of_full_name;
+
 	/* Matches ACPI */
 	const struct mfd_cell_acpi_match	*acpi_match;
 
-- 
1.8.3.1