linux-kernel - [PATCH v1 2/2] of: platform: Mark bus devices nodes with FWNODE_FLAG_NEVER

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Message-Id: <20210902025528.1017391-3-saravanak@google.com>
Date:   Wed,  1 Sep 2021 19:55:27 -0700
From:   Saravana Kannan <saravanak@...gle.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Len Brown <lenb@...nel.org>
Cc:     Saravana Kannan <saravanak@...gle.com>,
        Ulf Hansson <ulf.hansson@...aro.org>, kernel-team@...roid.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-acpi@...r.kernel.org
Subject: [PATCH v1 2/2] of: platform: Mark bus devices nodes with FWNODE_FLAG_NEVER_PROBES

We don't want fw_devlink creating device links for bus devices as
they'll never probe. So mark those device node with this flag.

Signed-off-by: Saravana Kannan <saravanak@...gle.com>
---
 drivers/of/platform.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 74afbb7a4f5e..42b3936d204a 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -392,6 +392,22 @@ static int of_platform_bus_create(struct device_node *bus,
 	if (!dev || !of_match_node(matches, bus))
 		return 0;
 
+	/*
+	 * If the bus node has only one compatible string value and it has
+	 * matched as a bus node, it's never going to get probed by a device
+	 * driver. So flag it as such so that fw_devlink knows not to create
+	 * device links with this device.
+	 *
+	 * This doesn't catch all devices that'll never probe, but this is good
+	 * enough for now.
+	 *
+	 * This doesn't really work for PPC because of how it uses
+	 * of_platform_bus_probe() to add normal devices. So ignore PPC cases.
+	 */
+	if (!IS_ENABLED(CONFIG_PPC) &&
+	    of_property_count_strings(bus, "compatible") == 1)
+		bus->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE;
+
 	for_each_child_of_node(bus, child) {
 		pr_debug("   create child: %pOF\n", child);
 		rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
-- 
2.33.0.259.gc128427fd7-goog