From: Hugo Dupras <h-dupras@xxxxxx>
By calling poll() on the /sys/class/gpio/gpioN/value sysfs file, usermode
application can take benefit of gpio interrupts.
However, depending on the power state reached, this interrupt may not wake-up
the CPU.
This patch creates a new sysfs file /sys/class/gpio/gpioN/irq_wake to enable
usermode application to set the wake properties of a gpio IRQ.
This option can be set or not for each gpio to preserve power consumption (e.g
embedded systems).
Signed-off-by: Hugo Dupras <h-dupras@xxxxxx>
Signed-off-by: Patrick Combes <p-combes@xxxxxx>
---
drivers/gpio/gpiolib.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 54 insertions(+), 1 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a971e3d..cf03aed 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -543,6 +543,55 @@ static ssize_t gpio_active_low_store(struct device *dev,
static const DEVICE_ATTR(active_low, 0644,
gpio_active_low_show, gpio_active_low_store);
+static ssize_t gpio_irq_wake_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ unsigned gpio = desc - gpio_desc;
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else if (sysfs_streq(buf, "enable") || sysfs_streq(buf, "1"))
+ status = enable_irq_wake(gpio_to_irq(gpio));
+ else if (sysfs_streq(buf, "disable") || sysfs_streq(buf, "0"))
+ status = disable_irq_wake(gpio_to_irq(gpio));
+ else
+ status = -EINVAL;
+
+ mutex_unlock(&sysfs_lock);
+
+ return status ? : size;
+}
+
+static ssize_t gpio_irq_wake_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ unsigned gpio = desc - gpio_desc;
+ int irq = gpio_to_irq(gpio);
+ ssize_t status;
+ struct irq_data *gpio_irq_data = irq_get_irq_data(irq);
+
+ mutex_lock(&sysfs_lock);
+
+ if (gpio_irq_data)
+ status = sprintf(buf, " Wakeup %s\n",
+ irqd_is_wakeup_set(gpio_irq_data)
+ ? " enable" : "disable");
+ else
+ status = -EINVAL;
+
+ mutex_unlock(&sysfs_lock);
+
+ return status;
+}
+
+static const DEVICE_ATTR(irq_wake, 0644,
+ gpio_irq_wake_show, gpio_irq_wake_store);
+
static const struct attribute *gpio_attrs[] = {
&dev_attr_value.attr,
&dev_attr_active_low.attr,
@@ -744,9 +793,13 @@ int gpio_export(unsigned gpio, bool direction_may_change)
if (!status && gpio_to_irq(gpio) >= 0
&& (direction_may_change
|| !test_bit(FLAG_IS_OUT,
- &desc->flags)))
+ &desc->flags))) {
status = device_create_file(dev,
&dev_attr_edge);
+ if (!status)
+ status = device_create_file(dev,
+ &dev_attr_irq_wake);
+ }
if (status != 0)
device_unregister(dev);
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
