linux-kernel - [PATCH 2/2] hwmon: (ltc2992) use fwnode_for_each_available_child_node

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Date: Wed, 22 May 2024 11:18:08 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 "Rafael J. Wysocki" <rafael@...nel.org>, 
 Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
 Daniel Scally <djrscally@...il.com>, 
 Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
 Sakari Ailus <sakari.ailus@...ux.intel.com>, 
 Jean Delvare <jdelvare@...e.com>, Guenter Roeck <linux@...ck-us.net>, 
 Antoniu Miclaus <antoniu.miclaus@...log.com>, 
 Jonathan Cameron <jic23@...nel.org>
Cc: linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-hwmon@...r.kernel.org, 
 Javier Carrasco <javier.carrasco.cruz@...il.com>
Subject: [PATCH 2/2] hwmon: (ltc2992) use
 fwnode_for_each_available_child_node_scoped()

The error path from a zero value of the "shunt-resistor-micro-ohms"
property does not decrement the refcount of the child node.

Instead of adding the missing fwnode_handle_put(), a safer fix for
future modifications is using the _scoped version of the macro,
which removes the need for fwnode_handle_put() in all error paths.

The macro defines the child node internally, which removes the need for
the current child node declaration as well.

Fixes: 10b029020487 ("hwmon: (ltc2992) Avoid division by zero")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
---
 drivers/hwmon/ltc2992.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/ltc2992.c b/drivers/hwmon/ltc2992.c
index 229aed15d5ca..3feee400ecf8 100644
--- a/drivers/hwmon/ltc2992.c
+++ b/drivers/hwmon/ltc2992.c
@@ -855,24 +855,19 @@ static const struct regmap_config ltc2992_regmap_config = {
 static int ltc2992_parse_dt(struct ltc2992_state *st)
 {
 	struct fwnode_handle *fwnode;
-	struct fwnode_handle *child;
 	u32 addr;
 	u32 val;
 	int ret;

 	fwnode = dev_fwnode(&st->client->dev);

-	fwnode_for_each_available_child_node(fwnode, child) {
+	fwnode_for_each_available_child_node_scoped(fwnode, child) {
 		ret = fwnode_property_read_u32(child, "reg", &addr);
-		if (ret < 0) {
-			fwnode_handle_put(child);
+		if (ret < 0)
 			return ret;
-		}

-		if (addr > 1) {
-			fwnode_handle_put(child);
+		if (addr > 1)
 			return -EINVAL;
-		}

 		ret = fwnode_property_read_u32(child, "shunt-resistor-micro-ohms", &val);
 		if (!ret) {

-- 
2.40.1