linux-kernel - [RFC PATCH] reset: Add devm_reset_control

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Date: Thu, 18 Apr 2024 14:26:02 +0100
From: Prabhakar <prabhakar.csengg@...il.com>
To: Geert Uytterhoeven <geert+renesas@...der.be>,
	Philipp Zabel <p.zabel@...gutronix.de>
Cc: linux-kernel@...r.kernel.org,
	linux-renesas-soc@...r.kernel.org,
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
	Prabhakar <prabhakar.csengg@...il.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: [RFC PATCH] reset: Add devm_reset_control_deassert helper

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

A typical code pattern for reset_control_deassert() call is to call it in
the _probe function and to call reset_control_assert() both from _probe
error path and from _remove function.

Add helper function to replace this bolierplate piece of code. Calling
devm_reset_control_deassert() removes the need for calling
reset_control_assert() both in the probe()'s error path and in the
remove() function.

Suggested-by: Geert Uytterhoeven <geert+renesas@...der.be>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
---
 drivers/reset/core.c  | 22 ++++++++++++++++++++++
 include/linux/reset.h |  6 ++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index dba74e857be6..a2a6eff8e599 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -592,6 +592,28 @@ int reset_control_deassert(struct reset_control *rstc)
 }
 EXPORT_SYMBOL_GPL(reset_control_deassert);
 
+static void reset_control_assert_action(void *rstc)
+{
+	reset_control_assert(rstc);
+}
+
+/**
+ * devm_reset_control_deassert - devres-enabled version of reset_control_deassert()
+ * @dev: device that requests the reset control
+ * @rstc: reset controller
+ */
+int devm_reset_control_deassert(struct device *dev, struct reset_control *rstc)
+{
+	int ret;
+
+	ret = reset_control_deassert(rstc);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, reset_control_assert_action, rstc);
+}
+EXPORT_SYMBOL_GPL(devm_reset_control_deassert);
+
 /**
  * reset_control_bulk_deassert - deasserts the reset lines in reverse order
  * @num_rstcs: number of entries in rstcs array
diff --git a/include/linux/reset.h b/include/linux/reset.h
index 514ddf003efc..e41e752ba098 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -31,6 +31,7 @@ int reset_control_reset(struct reset_control *rstc);
 int reset_control_rearm(struct reset_control *rstc);
 int reset_control_assert(struct reset_control *rstc);
 int reset_control_deassert(struct reset_control *rstc);
+int devm_reset_control_deassert(struct device *dev, struct reset_control *rstc);
 int reset_control_status(struct reset_control *rstc);
 int reset_control_acquire(struct reset_control *rstc);
 void reset_control_release(struct reset_control *rstc);
@@ -91,6 +92,11 @@ static inline int reset_control_deassert(struct reset_control *rstc)
 	return 0;
 }
 
+static inline int devm_reset_control_deassert(struct device *dev, struct reset_control *rstc)
+{
+	return 0;
+}
+
 static inline int reset_control_status(struct reset_control *rstc)
 {
 	return 0;
-- 
2.34.1