linux-kernel - [PATCH v2] docs: driver-api pinctrl cleanup

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Message-ID: <20250827074525.685863-1-alex.t.tran@gmail.com>
Date: Wed, 27 Aug 2025 00:45:25 -0700
From: Alex Tran <alex.t.tran@...il.com>
To: linus.walleij@...aro.org
Cc: corbet@....net,
	linux-gpio@...r.kernel.org,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Alex Tran <alex.t.tran@...il.com>
Subject: [PATCH v2] docs: driver-api pinctrl cleanup

changelog:
v2
Replace FIXME comments in the pinctrl documentation example with
proper cleanup code:
- Add devm_pinctrl_put() calls in error paths 
  (pinctrl_lookup_state, pinctrl_select_state) 
  after successful devm_pinctrl_get()
- Set foo->p to NULL when devm_pinctrl_get() fails
- Add ret variable for cleaner error handling
- provides proper example of pinctrl resource management on failure

Signed-off-by: Alex Tran <alex.t.tran@...il.com>
---
 Documentation/driver-api/pin-control.rst | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/driver-api/pin-control.rst b/Documentation/driver-api/pin-control.rst
index 27ea12363..281533c33 100644
--- a/Documentation/driver-api/pin-control.rst
+++ b/Documentation/driver-api/pin-control.rst
@@ -1202,22 +1202,24 @@ default state like this:
 	{
 		/* Allocate a state holder named "foo" etc */
 		struct foo_state *foo = ...;
+		int ret;
 
 		foo->p = devm_pinctrl_get(&device);
 		if (IS_ERR(foo->p)) {
-			/* FIXME: clean up "foo" here */
-			return PTR_ERR(foo->p);
+			ret = PTR_ERR(foo->p);
+			foo->p = NULL;
+			return ret;
 		}
 
 		foo->s = pinctrl_lookup_state(foo->p, PINCTRL_STATE_DEFAULT);
 		if (IS_ERR(foo->s)) {
-			/* FIXME: clean up "foo" here */
+			devm_pinctrl_put(foo->p);
 			return PTR_ERR(foo->s);
 		}
 
 		ret = pinctrl_select_state(foo->p, foo->s);
 		if (ret < 0) {
-			/* FIXME: clean up "foo" here */
+			devm_pinctrl_put(foo->p);
 			return ret;
 		}
 	}
-- 
2.51.0