Add "parent_trigger" sysfs attribute to iio trigger to be able to set a parent to the current trigger. Introduce validate_trigger function in iio_trigger_ops which does the same than validate_device but with a trigger as second parameter.
Signed-off-by: Benjamin Gaignard <[email protected]> --- .../ABI/testing/sysfs-bus-iio-trigger-sysfs | 8 +++ drivers/iio/industrialio-trigger.c | 68 ++++++++++++++++++++++ include/linux/iio/trigger.h | 6 +- 3 files changed, 81 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs b/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs index 04ac623..179fc0c 100644 --- a/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs +++ b/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs @@ -40,3 +40,11 @@ Description: associated file, representing the id of the trigger that needs to be removed. If the trigger can't be found, an invalid argument message will be returned to the user. + +What: /sys/bus/iio/devices/triggerX/parent_trigger +KernelVersion: 4.12 +Contact: [email protected] +Description: + This attribute is used to set a trigger as parent for the + current trigger. If the trigger can't use the parent an + invalid argument message will be returned. diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c index 978729f..5eda996 100644 --- a/drivers/iio/industrialio-trigger.c +++ b/drivers/iio/industrialio-trigger.c @@ -58,8 +58,76 @@ static ssize_t iio_trigger_read_name(struct device *dev, static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL); +/** + * iio_trigger_read_parent() - trigger consumer sysfs query parent trigger + * @dev: device associated with an industrial I/O trigger + * @attr: pointer to the device_attribute structure that + * is being processed + * @buf: buffer where the current trigger name will be printed into + * + * Return: a negative number on failure, the number of characters written + * on success or 0 if no trigger is available + */ +static ssize_t iio_trigger_read_parent(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_trigger *trig = to_iio_trigger(dev); + + if (trig->parent_trigger) + return sprintf(buf, "%s\n", trig->parent_trigger->name); + + return 0; +} + +static struct iio_trigger *iio_trigger_find_by_name(const char *name, + size_t len); + +/** + * iio_trigger_write_parent() - trigger consumer sysfs set parent trigger + * @dev: device associated with an industrial I/O trigger + * @attr: device attribute that is being processed + * @buf: string buffer that holds the name of the trigger + * @len: length of the trigger name held by buf + * + * Return: negative error code on failure or length of the buffer + * on success + */ +static ssize_t iio_trigger_write_parent(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + struct iio_trigger *parent; + struct iio_trigger *child = to_iio_trigger(dev); + int ret; + + if (!child->ops->validate_trigger) + return -EINVAL; + + if (atomic_read(&child->use_count)) + return -EBUSY; + + parent = iio_trigger_find_by_name(buf, len); + + if (parent == child->parent_trigger) + return len; + + ret = child->ops->validate_trigger(child, parent); + if (ret) + return ret; + + child->parent_trigger = parent; + + return len; +} +static DEVICE_ATTR(parent_trigger, S_IRUGO | S_IWUSR, + iio_trigger_read_parent, + iio_trigger_write_parent); + static struct attribute *iio_trig_dev_attrs[] = { &dev_attr_name.attr, + &dev_attr_parent_trigger.attr, NULL, }; ATTRIBUTE_GROUPS(iio_trig_dev); diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h index ea08302..16e39ee 100644 --- a/include/linux/iio/trigger.h +++ b/include/linux/iio/trigger.h @@ -29,6 +29,7 @@ struct iio_subirq { * use count is zero (may be NULL) * @validate_device: function to validate the device when the * current trigger gets changed. + * @validate_trigger: function to validate the parent trigger (may be NULL) * * This is typically static const within a driver and shared by * instances of a given device. @@ -39,9 +40,10 @@ struct iio_trigger_ops { int (*try_reenable)(struct iio_trigger *trig); int (*validate_device)(struct iio_trigger *trig, struct iio_dev *indio_dev); + int (*validate_trigger)(struct iio_trigger *trig, + struct iio_trigger *parent); }; - /** * struct iio_trigger - industrial I/O trigger device * @ops: [DRIVER] operations structure @@ -59,6 +61,7 @@ struct iio_trigger_ops { * @attached_own_device:[INTERN] if we are using our own device as trigger, * i.e. if we registered a poll function to the same * device as the one providing the trigger. + * @parent_trigger: [INTERN] parent trigger **/ struct iio_trigger { const struct iio_trigger_ops *ops; @@ -77,6 +80,7 @@ struct iio_trigger { unsigned long pool[BITS_TO_LONGS(CONFIG_IIO_CONSUMERS_PER_TRIGGER)]; struct mutex pool_lock; bool attached_own_device; + struct iio_trigger *parent_trigger; }; -- 1.9.1
