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 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'include/linux/gpio/consumer.h') 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) { -- cgit v1.2.3 From 8e53b0f190af2954309bbad76a78177ead15d824 Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Tue, 25 Nov 2014 17:16:31 +0900 Subject: gpio: remove const modifier from gpiod_get_direction() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Although gpiod_get_direction() can be considered side-effect free for consumers, its internals involve setting or clearing bits in the affected GPIO descriptor, for which we need to force-cast the const descriptor variable to non-const. This could lead to incorrect behavior if the compiler decides to optimize here, so remove this const attribute. The intent is to make gpiod_get_direction() private anyway, so it does not really matter. Reported-by: Uwe Kleine-König Signed-off-by: Alexandre Courbot Acked-by: Uwe Kleine-König Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib-sysfs.c | 2 +- drivers/gpio/gpiolib.c | 8 +++----- include/linux/gpio/consumer.h | 2 +- 3 files changed, 5 insertions(+), 7 deletions(-) (limited to 'include/linux/gpio/consumer.h') diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index 781fbed00fc3..2ac1800b58bb 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -41,7 +41,7 @@ static DEFINE_MUTEX(sysfs_lock); static ssize_t gpio_direction_show(struct device *dev, struct device_attribute *attr, char *buf) { - const struct gpio_desc *desc = dev_get_drvdata(dev); + struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 5619922ebf44..0b271ef87c09 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -148,7 +148,7 @@ static int gpiochip_find_base(int ngpio) * * This function may sleep if gpiod_cansleep() is true. */ -int gpiod_get_direction(const struct gpio_desc *desc) +int gpiod_get_direction(struct gpio_desc *desc) { struct gpio_chip *chip; unsigned offset; @@ -164,13 +164,11 @@ int gpiod_get_direction(const struct gpio_desc *desc) if (status > 0) { /* GPIOF_DIR_IN, or other positive */ status = 1; - /* FLAG_IS_OUT is just a cache of the result of get_direction(), - * so it does not affect constness per se */ - clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); + clear_bit(FLAG_IS_OUT, &desc->flags); } if (status == 0) { /* GPIOF_DIR_OUT */ - set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); + set_bit(FLAG_IS_OUT, &desc->flags); } return status; } diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h index 83c0a61c605d..d54d158ca327 100644 --- a/include/linux/gpio/consumer.h +++ b/include/linux/gpio/consumer.h @@ -66,7 +66,7 @@ __devm_gpiod_get_index_optional(struct device *dev, const char *con_id, unsigned int index, enum gpiod_flags flags); void devm_gpiod_put(struct device *dev, struct gpio_desc *desc); -int gpiod_get_direction(const struct gpio_desc *desc); +int gpiod_get_direction(struct gpio_desc *desc); int gpiod_direction_input(struct gpio_desc *desc); int gpiod_direction_output(struct gpio_desc *desc, int value); int gpiod_direction_output_raw(struct gpio_desc *desc, int value); -- cgit v1.2.3