linux-kernel - [PATCH] gpiolib: Add comments explaining the _cansleep() WARN

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Message-Id: <1329503041-11517-1-git-send-email-broonie@opensource.wolfsonmicro.com>
Date:	Fri, 17 Feb 2012 10:24:01 -0800
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Grant Likely <grant.likely@...retlab.ca>,
	Linus Walleij <linus.walleij@...ricsson.com>
Cc:	linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [PATCH] gpiolib: Add comments explaining the _cansleep() WARN_ON()s

I've seen users getting very confused by the WARN_ON()s for can_sleep
GPIOs in the atomic-safe paths, the discoverability of the non-atomic
version of the API seems to be hampered by the fact that it's defined
in a header file not the .c file where the warnings are.

Add a couple of comments next to the warnings to help people on their
way.

Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
---
 drivers/gpio/gpiolib.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 17fdf4b..2513af6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1560,6 +1560,7 @@ int __gpio_get_value(unsigned gpio)
 	int value;
 
 	chip = gpio_to_chip(gpio);
+	/* Should be using gpio_get_value_cansleep() or a different GPIO */
 	WARN_ON(chip->can_sleep);
 	value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
 	trace_gpio_value(gpio, 1, value);
@@ -1581,6 +1582,7 @@ void __gpio_set_value(unsigned gpio, int value)
 	struct gpio_chip	*chip;
 
 	chip = gpio_to_chip(gpio);
+	/* Should be using gpio_set_value_cansleep() or a different GPIO */
 	WARN_ON(chip->can_sleep);
 	trace_gpio_value(gpio, 0, value);
 	chip->set(chip, gpio - chip->base, value);
-- 
1.7.9.rc1

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