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From:   Bartosz Golaszewski <brgl@bgdev.pl>
To:     Linus Walleij <linus.walleij@linaro.org>
Cc:     linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        "Claus H . Stovgaard" <cst@phaseone.com>
Subject: [PATCH] gpio: don't WARN() on NULL descs if gpiolib is disabled
Date:   Mon,  8 Jul 2019 10:23:43 +0200
Message-Id: <20190708082343.30726-1-brgl@bgdev.pl>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

If gpiolib is disabled, we use the inline stubs from gpio/consumer.h
instead of regular definitions of GPIO API. The stubs for 'optional'
variants of gpiod_get routines return NULL in this case as if the
relevant GPIO wasn't found. This is correct so far.

Calling other (non-gpio_get) stubs from this header triggers a warning
because the GPIO descriptor couldn't have been requested. The warning
however is unconditional (WARN_ON(1)) and is emitted even if the passed
descriptor pointer is NULL.

We don't want to force the users of 'optional' gpio_get to check the
returned pointer before calling e.g. gpiod_set_value() so let's only
WARN on non-NULL descriptors.

Reported-by: Claus H. Stovgaard <cst@phaseone.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 include/linux/gpio/consumer.h | 64 +++++++++++++++++------------------
 1 file changed, 32 insertions(+), 32 deletions(-)

diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 9ddcf50a3c59..a7f08fb0f865 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -247,7 +247,7 @@ static inline void gpiod_put(struct gpio_desc *desc)
 	might_sleep();
 
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 }
 
 static inline void devm_gpiod_unhinge(struct device *dev,
@@ -256,7 +256,7 @@ static inline void devm_gpiod_unhinge(struct device *dev,
 	might_sleep();
 
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 }
 
 static inline void gpiod_put_array(struct gpio_descs *descs)
@@ -264,7 +264,7 @@ static inline void gpiod_put_array(struct gpio_descs *descs)
 	might_sleep();
 
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(descs);
 }
 
 static inline struct gpio_desc *__must_check
@@ -317,7 +317,7 @@ static inline void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
 	might_sleep();
 
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 }
 
 static inline void devm_gpiod_put_array(struct device *dev,
@@ -326,32 +326,32 @@ static inline void devm_gpiod_put_array(struct device *dev,
 	might_sleep();
 
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(descs);
 }
 
 
 static inline int gpiod_get_direction(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -ENOSYS;
 }
 static inline int gpiod_direction_input(struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -ENOSYS;
 }
 static inline int gpiod_direction_output(struct gpio_desc *desc, int value)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -ENOSYS;
 }
 static inline int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -ENOSYS;
 }
 
@@ -359,7 +359,7 @@ static inline int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 static inline int gpiod_get_value(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return 0;
 }
 static inline int gpiod_get_array_value(unsigned int array_size,
@@ -368,13 +368,13 @@ static inline int gpiod_get_array_value(unsigned int array_size,
 					unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 static inline void gpiod_set_value(struct gpio_desc *desc, int value)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 }
 static inline int gpiod_set_array_value(unsigned int array_size,
 					struct gpio_desc **desc_array,
@@ -382,13 +382,13 @@ static inline int gpiod_set_array_value(unsigned int array_size,
 					unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 static inline int gpiod_get_raw_value(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return 0;
 }
 static inline int gpiod_get_raw_array_value(unsigned int array_size,
@@ -397,13 +397,13 @@ static inline int gpiod_get_raw_array_value(unsigned int array_size,
 					    unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 static inline void gpiod_set_raw_value(struct gpio_desc *desc, int value)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 }
 static inline int gpiod_set_raw_array_value(unsigned int array_size,
 					    struct gpio_desc **desc_array,
@@ -411,14 +411,14 @@ static inline int gpiod_set_raw_array_value(unsigned int array_size,
 					    unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 
 static inline int gpiod_get_value_cansleep(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return 0;
 }
 static inline int gpiod_get_array_value_cansleep(unsigned int array_size,
@@ -427,13 +427,13 @@ static inline int gpiod_get_array_value_cansleep(unsigned int array_size,
 				     unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 static inline void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 }
 static inline int gpiod_set_array_value_cansleep(unsigned int array_size,
 					    struct gpio_desc **desc_array,
@@ -441,13 +441,13 @@ static inline int gpiod_set_array_value_cansleep(unsigned int array_size,
 					    unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 static inline int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return 0;
 }
 static inline int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
@@ -456,14 +456,14 @@ static inline int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
 					       unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 static inline void gpiod_set_raw_value_cansleep(struct gpio_desc *desc,
 						int value)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 }
 static inline int gpiod_set_raw_array_value_cansleep(unsigned int array_size,
 						struct gpio_desc **desc_array,
@@ -471,41 +471,41 @@ static inline int gpiod_set_raw_array_value_cansleep(unsigned int array_size,
 						unsigned long *value_bitmap)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 	return 0;
 }
 
 static inline int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -ENOSYS;
 }
 
 static inline int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -ENOSYS;
 }
 
 static inline int gpiod_is_active_low(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return 0;
 }
 static inline int gpiod_cansleep(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return 0;
 }
 
 static inline int gpiod_to_irq(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -EINVAL;
 }
 
@@ -513,7 +513,7 @@ static inline int gpiod_set_consumer_name(struct gpio_desc *desc,
 					  const char *name)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -EINVAL;
 }
 
@@ -525,7 +525,7 @@ static inline struct gpio_desc *gpio_to_desc(unsigned gpio)
 static inline int desc_to_gpio(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc);
 	return -EINVAL;
 }
 
-- 
2.21.0