[PATCH v4 12/16] firmware: arm_scmi: Fix OF node reference handling

[Sudeep Holla <sudeep.holla@kernel.org>]

SCMI devices store the DT node in dev.of_node through
device_set_node(), but that helper only assigns the fwnode and
of_node pointers without taking an OF node reference.

Take a reference when assigning the node and release it from the
SCMI device release path. With the device owning that reference,
remove the separate channel-side get/put pair from the core driver.

Fixes: 96da4a99ce50 ("firmware: arm_scmi: Set fwnode for the scmi_device")
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
 drivers/firmware/arm_scmi/bus.c    | 3 ++-
 drivers/firmware/arm_scmi/driver.c | 4 ----
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index dcaefc1aa892..a14df82a9310 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -401,6 +401,7 @@ static void scmi_device_release(struct device *dev)
 	struct scmi_device *scmi_dev = to_scmi_dev(dev);
 
 	scmi_device_release_syspower(scmi_dev);
+	of_node_put(dev->of_node);
 	kfree_const(scmi_dev->name);
 	kfree(scmi_dev);
 }
@@ -464,7 +465,7 @@ __scmi_device_create(struct device_node *np, struct device *parent,
 
 	scmi_dev->id = id;
 	scmi_dev->dev.parent = parent;
-	device_set_node(&scmi_dev->dev, of_fwnode_handle(np));
+	device_set_node(&scmi_dev->dev, of_fwnode_handle(of_node_get(np)));
 	scmi_dev->dev.bus = &scmi_bus_type;
 	scmi_dev->dev.release = scmi_device_release;
 	dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id);
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 3e0f0fac9626..515ae884bb2c 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -2789,14 +2789,12 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
 		devm_kfree(info->dev, cinfo);
 		return -EINVAL;
 	}
-	of_node_get(of_node);
 
 	cinfo->id = prot_id;
 	cinfo->dev = &tdev->dev;
 	cinfo->handle = &info->handle;
 	ret = info->desc->ops->chan_setup(cinfo, info->dev, tx);
 	if (ret) {
-		of_node_put(of_node);
 		scmi_device_destroy(info->dev, prot_id, name);
 		devm_kfree(info->dev, cinfo);
 		return ret;
@@ -2820,7 +2818,6 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
 		/* Destroy channel and device only if created by this call. */
 		if (tdev) {
 			info->desc->ops->chan_free(prot_id, cinfo, idr);
-			of_node_put(of_node);
 			scmi_device_destroy(info->dev, prot_id, name);
 			devm_kfree(info->dev, cinfo);
 		}
@@ -2906,7 +2903,6 @@ static int scmi_chan_destroy(int id, void *p, void *data)
 		struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
 		struct scmi_device *sdev = to_scmi_dev(cinfo->dev);
 
-		of_node_put(cinfo->dev->of_node);
 		scmi_device_destroy(info->dev, cinfo->id, sdev->name);
 		cinfo->dev = NULL;
 	}

-- 
2.43.0