| Message ID | 1487947695-9305-2-git-send-email-benjamin.gaignard@st.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add parent_trigger attribute to triggers | expand |
On 24/02/17 14:48, Benjamin Gaignard wrote: > Add "parent_trigger" sysfs attribute to iio trigger to be able > to set a parent to the current trigger. > Parent trigger edges or levels could be used to control current > trigger status for example to start, stop or reset it. > > Introduce validate_trigger function in iio_trigger_ops which does > the same than validate_device but with a trigger as second parameter. > Driver must implement this function and add dev_attr_parent_trigger > in their trigger attribute group to be able to use parent trigger > feature. > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com> It might be worth a cover letter for this series with even more detail, or perhaps even a proposed page for the sphinx docs. It's interesting stuff, but not necessarily obvious to a newcomer to this discussion. We really need to expand those sphinx docs anyway. I was thinking of a whole series of pages on 'weird / sophiscated' usage of IIO, touching on stuff like Peter Rosin's analog front ends and Matt Ranostay's more novel health and chemical sensors. i.e. the stuff that 'stretches' us ;) Jonathan > > version 3: > - try to provide better description of parent_trigger usages > > version 2: > - add comment about parent trigger usage > - parent trigger attribute must be set the driver no more by IIO core > --- > .../ABI/testing/sysfs-bus-iio-trigger-sysfs | 15 +++++ > drivers/iio/industrialio-trigger.c | 69 ++++++++++++++++++++++ > include/linux/iio/trigger.h | 7 ++- > 3 files changed, 90 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..1e7fc40 100644 > --- a/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs > +++ b/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs > @@ -40,3 +40,18 @@ 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: linux-iio@vger.kernel.org > +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. > + Parent trigger edges or levels could be used to control current > + trigger. For example current trigger could be started on parent > + rising edges or be enabled only when parent trigger level is > + high. > + Since there is many ways to use parent edges and levels to > + control current trigger behavoir an additional custom sysfs > + attribute may be needed to describe those control modes. The only bit I'd change in here is dropping the word custom. I'm an optimist: We may yet figure out a nice generic interface! > diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c > index 978729f..9891fb2 100644 > --- a/drivers/iio/industrialio-trigger.c > +++ b/drivers/iio/industrialio-trigger.c > @@ -58,6 +58,74 @@ 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; > +} > + > +DEVICE_ATTR(parent_trigger, S_IRUGO | S_IWUSR, > + iio_trigger_read_parent, iio_trigger_write_parent); > +EXPORT_SYMBOL_GPL(dev_attr_parent_trigger); > + > static struct attribute *iio_trig_dev_attrs[] = { > &dev_attr_name.attr, > NULL, > @@ -440,6 +508,7 @@ static ssize_t iio_trigger_write_current(struct device *dev, > indio_dev->pollfunc_event); > iio_trigger_put(oldtrig); > } > + > if (indio_dev->trig) { > iio_trigger_get(indio_dev->trig); > if (indio_dev->modes & INDIO_EVENT_TRIGGERED) > diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h > index ea08302..efa2983 100644 > --- a/include/linux/iio/trigger.h > +++ b/include/linux/iio/trigger.h > @@ -20,6 +20,7 @@ struct iio_subirq { > > struct iio_dev; > struct iio_trigger; > +extern struct device_attribute dev_attr_parent_trigger; > > /** > * struct iio_trigger_ops - operations structure for an iio_trigger. > @@ -29,6 +30,7 @@ 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 +41,10 @@ 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 +62,7 @@ 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 +81,7 @@ 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; > }; > > >
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs b/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs index 04ac623..1e7fc40 100644 --- a/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs +++ b/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs @@ -40,3 +40,18 @@ 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: linux-iio@vger.kernel.org +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. + Parent trigger edges or levels could be used to control current + trigger. For example current trigger could be started on parent + rising edges or be enabled only when parent trigger level is + high. + Since there is many ways to use parent edges and levels to + control current trigger behavoir an additional custom sysfs + attribute may be needed to describe those control modes. diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c index 978729f..9891fb2 100644 --- a/drivers/iio/industrialio-trigger.c +++ b/drivers/iio/industrialio-trigger.c @@ -58,6 +58,74 @@ 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; +} + +DEVICE_ATTR(parent_trigger, S_IRUGO | S_IWUSR, + iio_trigger_read_parent, iio_trigger_write_parent); +EXPORT_SYMBOL_GPL(dev_attr_parent_trigger); + static struct attribute *iio_trig_dev_attrs[] = { &dev_attr_name.attr, NULL, @@ -440,6 +508,7 @@ static ssize_t iio_trigger_write_current(struct device *dev, indio_dev->pollfunc_event); iio_trigger_put(oldtrig); } + if (indio_dev->trig) { iio_trigger_get(indio_dev->trig); if (indio_dev->modes & INDIO_EVENT_TRIGGERED) diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h index ea08302..efa2983 100644 --- a/include/linux/iio/trigger.h +++ b/include/linux/iio/trigger.h @@ -20,6 +20,7 @@ struct iio_subirq { struct iio_dev; struct iio_trigger; +extern struct device_attribute dev_attr_parent_trigger; /** * struct iio_trigger_ops - operations structure for an iio_trigger. @@ -29,6 +30,7 @@ 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 +41,10 @@ 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 +62,7 @@ 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 +81,7 @@ 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; };
Add "parent_trigger" sysfs attribute to iio trigger to be able to set a parent to the current trigger. Parent trigger edges or levels could be used to control current trigger status for example to start, stop or reset it. Introduce validate_trigger function in iio_trigger_ops which does the same than validate_device but with a trigger as second parameter. Driver must implement this function and add dev_attr_parent_trigger in their trigger attribute group to be able to use parent trigger feature. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com> version 3: - try to provide better description of parent_trigger usages version 2: - add comment about parent trigger usage - parent trigger attribute must be set the driver no more by IIO core --- .../ABI/testing/sysfs-bus-iio-trigger-sysfs | 15 +++++ drivers/iio/industrialio-trigger.c | 69 ++++++++++++++++++++++ include/linux/iio/trigger.h | 7 ++- 3 files changed, 90 insertions(+), 1 deletion(-) -- 1.9.1