gpio: don't WARN() on NULL descs if gpiolib is disabled

[ Upstream commit ffe0bbab ]

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.

Cc: stable@vger.kernel.org
Reported-by: Claus H. Stovgaard <cst@phaseone.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

include/linux/gpio/consumer.h

@@ -222,7 +222,7 @@ 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 gpiod_put_array(struct gpio_descs *descs)
@@ -230,7 +230,7 @@ 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
@@ -283,7 +283,7 @@ 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,
@@ -292,32 +292,32 @@ 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;
 }
 
@@ -325,7 +325,7 @@ 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,
@@ -333,25 +333,25 @@ static inline int gpiod_get_array_value(unsigned int array_size,
 					int *value_array)
 {
 	/* 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 void gpiod_set_array_value(unsigned int array_size,
 					 struct gpio_desc **desc_array,
 					 int *value_array)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 }
 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,
@@ -359,27 +359,27 @@ static inline int gpiod_get_raw_array_value(unsigned int array_size,
 					    int *value_array)
 {
 	/* 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,
 					     int *value_array)
 {
 	/* 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,
@@ -387,25 +387,25 @@ static inline int gpiod_get_array_value_cansleep(unsigned int array_size,
 				     int *value_array)
 {
 	/* 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 void gpiod_set_array_value_cansleep(unsigned int array_size,
 					    struct gpio_desc **desc_array,
 					    int *value_array)
 {
 	/* GPIO can never have been requested */
-	WARN_ON(1);
+	WARN_ON(desc_array);
 }
 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,
@@ -413,55 +413,55 @@ static inline int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
 					       int *value_array)
 {
 	/* 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,
 						int *value_array)
 {
 	/* 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;
 }
 
@@ -469,7 +469,7 @@ 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;
 }
 
@@ -481,7 +481,7 @@ 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;
 }