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Date: Tue, 8 Dec 2015 04:20:07 +0100 From: Peter Rosin <peda@...ator.liu.se> To: linux-gpio@...r.kernel.org Cc: Linus Walleij <linus.walleij@...aro.org>, Alexandre Courbot <gnurou@...il.com>, Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, Peter Rosin <peda@...ator.liu.se>, Peter Rosin <peda@...ntia.se> Subject: [RESEND RFC PATCH 1/2] gpio: Add isr property of gpio pins From: Peter Rosin <peda@...ntia.se> Adds the possibility to read the interrupt status register bit for the gpio pin. Expose the bit as an isr file in sysfs. Signed-off-by: Peter Rosin <peda@...ntia.se> --- Documentation/gpio/sysfs.txt | 12 ++++++++++++ drivers/gpio/gpiolib-sysfs.c | 30 ++++++++++++++++++++++++++++++ drivers/gpio/gpiolib.c | 15 +++++++++++++++ include/linux/gpio/consumer.h | 1 + include/linux/gpio/driver.h | 2 ++ 5 files changed, 60 insertions(+) diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt index 535b6a8a7a7c..ded7ef9d01be 100644 --- a/Documentation/gpio/sysfs.txt +++ b/Documentation/gpio/sysfs.txt @@ -97,6 +97,18 @@ and have the following read/write attributes: for "rising" and "falling" edges will follow this setting. + "isr" ... reads as either 0 (false) or 1 (true). Reading the + file will clear the value, so that reading a 1 means + that there has been an interrupt-triggering action + on the pin since the file was last read. + + This file exists only if the gpio chip supports reading + the interrupt status register bit for the pin. + + Note that if reading the isr register for this pin + interferes with active interrupts, the read will fail + with an error. + GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the controller implementing GPIOs starting at #42) and have the following read-only attributes: diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index b57ed8e55ab5..f6fe68fab191 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -139,6 +139,28 @@ static ssize_t value_store(struct device *dev, } static DEVICE_ATTR_RW(value); +static ssize_t isr_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; + ssize_t status; + int isr; + + mutex_lock(&data->mutex); + + isr = gpiod_get_isr_cansleep(desc); + if (isr < 0) + status = isr; + else + status = sprintf(buf, "%d\n", isr); + + mutex_unlock(&data->mutex); + + return status; +} +static DEVICE_ATTR_RO(isr); + static irqreturn_t gpio_sysfs_irq(int irq, void *priv) { struct gpiod_data *data = priv; @@ -367,6 +389,13 @@ static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, mode = 0; if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) mode = 0; + } else if (attr == &dev_attr_isr.attr) { + if (!desc->chip->get_isr) + mode = 0; + if (gpiod_to_irq(desc) < 0) + mode = 0; + if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) + mode = 0; } return mode; @@ -377,6 +406,7 @@ static struct attribute *gpio_attrs[] = { &dev_attr_edge.attr, &dev_attr_value.attr, &dev_attr_active_low.attr, + &dev_attr_isr.attr, NULL, }; diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index bf4bd1d120c3..b45e70b2713e 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1572,6 +1572,21 @@ int gpiod_get_value_cansleep(const struct gpio_desc *desc) } EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep); +int gpiod_get_isr_cansleep(const struct gpio_desc *desc) +{ + struct gpio_chip *chip; + int offset; + + might_sleep_if(extra_checks); + if (!desc) + return -EINVAL; + + chip = desc->chip; + offset = gpio_chip_hwgpio(desc); + return chip->get_isr ? chip->get_isr(chip, offset) : -ENXIO; +} +EXPORT_SYMBOL_GPL(gpiod_get_isr_cansleep); + /** * gpiod_set_raw_value_cansleep() - assign a gpio's raw value * @desc: gpio whose value will be assigned diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h index adac255aee86..d0290c14dc84 100644 --- a/include/linux/gpio/consumer.h +++ b/include/linux/gpio/consumer.h @@ -119,6 +119,7 @@ void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value); void gpiod_set_raw_array_value_cansleep(unsigned int array_size, struct gpio_desc **desc_array, int *value_array); +int gpiod_get_isr_cansleep(const struct gpio_desc *desc); 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 c8393cd4d44f..dccfb12f9112 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -96,6 +96,8 @@ struct gpio_chip { unsigned offset); void (*set)(struct gpio_chip *chip, unsigned offset, int value); + int (*get_isr)(struct gpio_chip *chip, + unsigned offset); void (*set_multiple)(struct gpio_chip *chip, unsigned long *mask, unsigned long *bits); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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