From 5f42424354f5b0ca5413b4fb8528d150692c85b7 Mon Sep 17 00:00:00 2001 From: Rojhalat Ibrahim Date: Tue, 4 Nov 2014 17:12:06 +0100 Subject: 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 Reviewed-by: Alexandre Courbot Reviewed-by: Mark Brown Signed-off-by: Linus Walleij --- include/linux/gpio/consumer.h | 38 ++++++++++++++++++++++++++++++++++++++ include/linux/gpio/driver.h | 4 ++++ 2 files changed, 42 insertions(+) (limited to 'include') 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); -- cgit v1.2.3