linux-kernel - [PATCH] regulator: core: Return error in get optional stub

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Date:	Thu, 17 Apr 2014 11:55:24 -0700
From:	Tim Kryger <tim.kryger@...aro.org>
To:	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>
CC:	Tim Kryger <tim.kryger@...aro.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH] regulator: core: Return error in get optional stub

Drivers that call regulator_get_optional are tolerant to the absence of
that regulator.  By modifying the value returned from the stub function
to match that seen when a regulator isn't present, callers can wrap the
regulator logic with an IS_ERR based conditional even if they happen to
call regulator_is_supported_voltage.  This improves efficiency as well
as eliminates the possibility for a very subtle bug.

Signed-off-by: Tim Kryger <tim.kryger@...aro.org>
Reviewed-by: Alex Elder <elder@...aro.org>
---

This change was proposed here: https://lkml.org/lkml/2014/4/16/627

 include/linux/regulator/consumer.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index e530681..1a4a8c1 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -258,14 +258,14 @@ regulator_get_exclusive(struct device *dev, const char *id)
 static inline struct regulator *__must_check
 regulator_get_optional(struct device *dev, const char *id)
 {
-	return NULL;
+	return ERR_PTR(-ENODEV);
 }
 
 
 static inline struct regulator *__must_check
 devm_regulator_get_optional(struct device *dev, const char *id)
 {
-	return NULL;
+	return ERR_PTR(-ENODEV);
 }
 
 static inline void regulator_put(struct regulator *regulator)
-- 
1.7.9.5

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