iio: core: move @trig_readonly from struct iio_dev to struct iio_dev_opaque

This is only set via the iio_trig_set_immutable() call and later used
by the IIO core so there is no benefit in drivers being able to access
it.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-5-jic23@kernel.org

drivers/iio/industrialio-trigger.c

@@ -117,14 +117,17 @@ EXPORT_SYMBOL(iio_trigger_unregister);
 
 int iio_trigger_set_immutable(struct iio_dev *indio_dev, struct iio_trigger *trig)
 {
+	struct iio_dev_opaque *iio_dev_opaque;
+
 	if (!indio_dev || !trig)
 		return -EINVAL;
 
+	iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	mutex_lock(&indio_dev->mlock);
-	WARN_ON(indio_dev->trig_readonly);
+	WARN_ON(iio_dev_opaque->trig_readonly);
 
 	indio_dev->trig = iio_trigger_get(trig);
-	indio_dev->trig_readonly = true;
+	iio_dev_opaque->trig_readonly = true;
 	mutex_unlock(&indio_dev->mlock);
 
 	return 0;
@@ -402,6 +405,7 @@ static ssize_t iio_trigger_write_current(struct device *dev,
 					 size_t len)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	struct iio_trigger *oldtrig = indio_dev->trig;
 	struct iio_trigger *trig;
 	int ret;
@@ -411,7 +415,7 @@ static ssize_t iio_trigger_write_current(struct device *dev,
 		mutex_unlock(&indio_dev->mlock);
 		return -EBUSY;
 	}
-	if (indio_dev->trig_readonly) {
+	if (iio_dev_opaque->trig_readonly) {
 		mutex_unlock(&indio_dev->mlock);
 		return -EPERM;
 	}

include/linux/iio/iio-opaque.h

@@ -8,6 +8,7 @@
  * @indio_dev:			public industrial I/O device information
  * @id:			used to identify device internally
  * @driver_module:		used to make it harder to undercut users
+ * @trig_readonly:		mark the current trigger immutable
  * @event_interface:		event chrdevs associated with interrupt lines
  * @attached_buffers:		array of buffers statically attached by the driver
  * @attached_buffers_cnt:	number of buffers in the array of statically attached buffers
@@ -30,6 +31,7 @@ struct iio_dev_opaque {
 	struct iio_dev			indio_dev;
 	int				id;
 	struct module			*driver_module;
+	bool				trig_readonly;
 	struct iio_event_interface	*event_interface;
 	struct iio_buffer		**attached_buffers;
 	unsigned int			attached_buffers_cnt;

include/linux/iio/iio.h

@@ -503,7 +503,6 @@ struct iio_buffer_setup_ops {
  * @scan_timestamp:	[INTERN] set if any buffers have requested timestamp
  * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
  * @trig:		[INTERN] current device trigger (buffer modes)
- * @trig_readonly:	[INTERN] mark the current trigger immutable
  * @pollfunc:		[DRIVER] function run on trigger being received
  * @pollfunc_event:	[DRIVER] function run on events trigger being received
  * @channels:		[DRIVER] channel specification structure table
@@ -535,7 +534,6 @@ struct iio_dev {
 	bool				scan_timestamp;
 	unsigned			scan_index_timestamp;
 	struct iio_trigger		*trig;
-	bool				trig_readonly;
 	struct iio_poll_func		*pollfunc;
 	struct iio_poll_func		*pollfunc_event;