[PATCH 1/5] iio: core: register buffer fileops only if buffer present

[Alexandru Ardelean <alexandru.ardelean@analog.com>]

The intent is to localize all buffer ops into the industrialio-buffer.c
file, to be able to add support for multiple buffers per IIO device.

We still need to allocate a chardev in __iio_device_register() to be able
to pass event ioctl commands. So, if the IIO device has no buffer, we
create the legacy chardev for the event ioctl() command.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/iio/industrialio-core.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 157d95a24faa..c8c074602709 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1707,6 +1707,15 @@ static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
 
 static const struct iio_buffer_setup_ops noop_ring_setup_ops;
 
+static const struct file_operations iio_event_fileops = {
+	.release = iio_chrdev_release,
+	.open = iio_chrdev_open,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = iio_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+};
+
 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
 {
 	int ret;
@@ -1757,7 +1766,10 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
 		indio_dev->setup_ops == NULL)
 		indio_dev->setup_ops = &noop_ring_setup_ops;
 
-	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
+	if (indio_dev->buffer)
+		cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
+	else
+		cdev_init(&indio_dev->chrdev, &iio_event_fileops);
 
 	indio_dev->chrdev.owner = this_mod;
 
-- 
2.17.1