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path: root/drivers/iio/industrialio-buffer.c
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Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
-rw-r--r--drivers/iio/industrialio-buffer.c33
1 files changed, 31 insertions, 2 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 7f9152c3c4d3..c67d83bdc8f0 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -37,6 +37,14 @@ static bool iio_buffer_is_active(struct iio_buffer *buf)
return !list_empty(&buf->buffer_list);
}
+static bool iio_buffer_data_available(struct iio_buffer *buf)
+{
+ if (buf->access->data_available)
+ return buf->access->data_available(buf);
+
+ return buf->stufftoread;
+}
+
/**
* iio_buffer_read_first_n_outer() - chrdev read for buffer access
*
@@ -48,13 +56,34 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
{
struct iio_dev *indio_dev = filp->private_data;
struct iio_buffer *rb = indio_dev->buffer;
+ int ret;
if (!indio_dev->info)
return -ENODEV;
if (!rb || !rb->access->read_first_n)
return -EINVAL;
- return rb->access->read_first_n(rb, n, buf);
+
+ do {
+ if (!iio_buffer_data_available(rb)) {
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(rb->pollq,
+ iio_buffer_data_available(rb) ||
+ indio_dev->info == NULL);
+ if (ret)
+ return ret;
+ if (indio_dev->info == NULL)
+ return -ENODEV;
+ }
+
+ ret = rb->access->read_first_n(rb, n, buf);
+ if (ret == 0 && (filp->f_flags & O_NONBLOCK))
+ ret = -EAGAIN;
+ } while (ret == 0);
+
+ return ret;
}
/**
@@ -70,7 +99,7 @@ unsigned int iio_buffer_poll(struct file *filp,
return -ENODEV;
poll_wait(filp, &rb->pollq, wait);
- if (rb->stufftoread)
+ if (iio_buffer_data_available(rb))
return POLLIN | POLLRDNORM;
/* need a way of knowing if there may be enough data... */
return 0;