iio: trigger: Add simple trigger_validation helper

Some triggers can only be attached to the IIO device that corresponds to
the same physical device. Implement generic helper which can be used as
a validate_trigger callback for such devices.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/51cd3e3e74a6addf8d333f4a109fb9c5a11086ee.1683541225.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index 784dc1e..f207e36 100644 (file)
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -322,7 +322,7 @@ int iio_trigger_attach_poll_func(struct iio_trigger *trig,
         * this is the case if the IIO device and the trigger device share the
         * same parent device.
         */
-       if (pf->indio_dev->dev.parent == trig->dev.parent)
+       if (iio_validate_own_trigger(pf->indio_dev, trig))
                trig->attached_own_device = true;
 
        return ret;
@@ -729,6 +729,26 @@ bool iio_trigger_using_own(struct iio_dev *indio_dev)
 EXPORT_SYMBOL(iio_trigger_using_own);
 
 /**
+ * iio_validate_own_trigger - Check if a trigger and IIO device belong to
+ *  the same device
+ * @idev: the IIO device to check
+ * @trig: the IIO trigger to check
+ *
+ * This function can be used as the validate_trigger callback for triggers that
+ * can only be attached to their own device.
+ *
+ * Return: 0 if both the trigger and the IIO device belong to the same
+ * device, -EINVAL otherwise.
+ */
+int iio_validate_own_trigger(struct iio_dev *idev, struct iio_trigger *trig)
+{
+       if (idev->dev.parent != trig->dev.parent)
+               return -EINVAL;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(iio_validate_own_trigger);
+
+/**
  * iio_trigger_validate_own_device - Check if a trigger and IIO device belong to
  *  the same device
  * @trig: The IIO trigger to check

diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h
index 51f52c5..bce3b17 100644 (file)
--- a/include/linux/iio/trigger.h
+++ b/include/linux/iio/trigger.h
@@ -171,6 +171,7 @@ void iio_trigger_free(struct iio_trigger *trig);
  */
 bool iio_trigger_using_own(struct iio_dev *indio_dev);
 
+int iio_validate_own_trigger(struct iio_dev *idev, struct iio_trigger *trig);
 int iio_trigger_validate_own_device(struct iio_trigger *trig,
                                     struct iio_dev *indio_dev);