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authorRojhalat Ibrahim <imr@rtschenk.de>2014-11-04 17:12:06 +0100
committerLinus Walleij <linus.walleij@linaro.org>2014-11-27 15:01:18 +0100
commit5f42424354f5b0ca5413b4fb8528d150692c85b7 (patch)
tree23ba183fa9976595adda4bceb006842a15eb3e19 /include/linux/gpio
parentb5b7b487431b01619f2947d91dadd7c7a233692e (diff)
gpiolib: allow simultaneous setting of multiple GPIO outputs
Introduce new functions gpiod_set_array & gpiod_set_raw_array to the consumer interface which allow setting multiple outputs with just one function call. Also add an optional set_multiple function to the driver interface. Without an implementation of that function in the chip driver outputs are set sequentially. Implementing the set_multiple function in a chip driver allows for: - Improved performance for certain use cases. The original motivation for this was the task of configuring an FPGA. In that specific case, where 9 GPIO lines have to be set many times, configuration time goes down from 48 s to 20 s when using the new function. - Simultaneous glitch-free setting of multiple pins on any kind of parallel bus attached to GPIOs provided they all reside on the same chip and bank. Limitations: Performance is only improved for normal high-low outputs. Open drain and open source outputs are always set separately from each other. Those kinds of outputs could probably be accelerated in a similar way if we could forgo the error checking when setting GPIO directions. Change log: v6: - rebase on current linux-gpio devel branch v5: - check can_sleep property per chip - remove superfluous checks - supplement documentation v4: - add gpiod_set_array function for setting logical values - change interface of the set_multiple driver function to use unsigned long as type for the bit fields - use generic bitops (which also use unsigned long for bit fields) - do not use ARCH_NR_GPIOS any more v3: - add documentation - change commit message v2: - use descriptor interface - allow arbitrary groups of GPIOs spanning multiple chips Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Mark Brown <broonie@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'include/linux/gpio')
-rw-r--r--include/linux/gpio/consumer.h38
-rw-r--r--include/linux/gpio/driver.h4
2 files changed, 42 insertions, 0 deletions
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 12f146fa6604..83c0a61c605d 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -74,14 +74,24 @@ int gpiod_direction_output_raw(struct gpio_desc *desc, int value);
/* Value get/set from non-sleeping context */
int gpiod_get_value(const struct gpio_desc *desc);
void gpiod_set_value(struct gpio_desc *desc, int value);
+void gpiod_set_array(unsigned int array_size,
+ struct gpio_desc **desc_array, int *value_array);
int gpiod_get_raw_value(const struct gpio_desc *desc);
void gpiod_set_raw_value(struct gpio_desc *desc, int value);
+void gpiod_set_raw_array(unsigned int array_size,
+ struct gpio_desc **desc_array, int *value_array);
/* Value get/set from sleeping context */
int gpiod_get_value_cansleep(const struct gpio_desc *desc);
void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
+void gpiod_set_array_cansleep(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array);
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc);
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value);
+void gpiod_set_raw_array_cansleep(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array);
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
@@ -210,6 +220,13 @@ static inline void gpiod_set_value(struct gpio_desc *desc, int value)
/* GPIO can never have been requested */
WARN_ON(1);
}
+static inline void gpiod_set_array(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+{
+ /* GPIO can never have been requested */
+ WARN_ON(1);
+}
static inline int gpiod_get_raw_value(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
@@ -221,6 +238,13 @@ static inline void gpiod_set_raw_value(struct gpio_desc *desc, int value)
/* GPIO can never have been requested */
WARN_ON(1);
}
+static inline void gpiod_set_raw_array(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+{
+ /* GPIO can never have been requested */
+ WARN_ON(1);
+}
static inline int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{
@@ -233,6 +257,13 @@ static inline void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
/* GPIO can never have been requested */
WARN_ON(1);
}
+static inline void gpiod_set_array_cansleep(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+{
+ /* GPIO can never have been requested */
+ WARN_ON(1);
+}
static inline int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
@@ -245,6 +276,13 @@ static inline void gpiod_set_raw_value_cansleep(struct gpio_desc *desc,
/* GPIO can never have been requested */
WARN_ON(1);
}
+static inline void gpiod_set_raw_array_cansleep(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+{
+ /* GPIO can never have been requested */
+ WARN_ON(1);
+}
static inline int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
{
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index ff200a75501e..c497c62889d1 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -32,6 +32,7 @@ struct seq_file;
* @get: returns value for signal "offset"; for output signals this
* returns either the value actually sensed, or zero
* @set: assigns output value for signal "offset"
+ * @set_multiple: assigns output values for multiple signals defined by "mask"
* @set_debounce: optional hook for setting debounce time for specified gpio in
* interrupt triggered gpio chips
* @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
@@ -89,6 +90,9 @@ struct gpio_chip {
unsigned offset);
void (*set)(struct gpio_chip *chip,
unsigned offset, int value);
+ void (*set_multiple)(struct gpio_chip *chip,
+ unsigned long *mask,
+ unsigned long *bits);
int (*set_debounce)(struct gpio_chip *chip,
unsigned offset,
unsigned debounce);