1 files changed, 24 insertions, 11 deletions

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 6eee1b044c60..d7e908acb480 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -71,8 +71,9 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
 
         if (avail >= to_wait) {
                 /* force a flush for non-blocking reads */
-                if (!to_wait && !avail && to_flush)
-                        iio_buffer_flush_hwfifo(indio_dev, buf, to_flush);
+                if (!to_wait && avail < to_flush)
+                        iio_buffer_flush_hwfifo(indio_dev, buf,
+                                                to_flush - avail);
                 return true;
         }
 
@@ -90,9 +91,16 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
 
 /**
  * iio_buffer_read_first_n_outer() - chrdev read for buffer access
+ * @filp:       File structure pointer for the char device
+ * @buf:        Destination buffer for iio buffer read
+ * @n:          First n bytes to read
+ * @f_ps:       Long offset provided by the user as a seek position
  *
  * This function relies on all buffer implementations having an
  * iio_buffer as their first element.
+ *
+ * Return: negative values corresponding to error codes or ret != 0
+ *         for ending the reading activity
  **/
 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
                                       size_t n, loff_t *f_ps)
@@ -100,8 +108,7 @@ 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;
         size_t datum_size;
-        size_t to_wait = 0;
-        size_t to_read;
+        size_t to_wait;
         int ret;
 
         if (!indio_dev->info)
@@ -119,14 +126,14 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
         if (!datum_size)
                 return 0;
 
-        to_read = min_t(size_t, n / datum_size, rb->watermark);
-
-        if (!(filp->f_flags & O_NONBLOCK))
-                to_wait = to_read;
+        if (filp->f_flags & O_NONBLOCK)
+                to_wait = 0;
+        else
+                to_wait = min_t(size_t, n / datum_size, rb->watermark);
 
         do {
                 ret = wait_event_interruptible(rb->pollq,
-                        iio_buffer_ready(indio_dev, rb, to_wait, to_read));
+                      iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size));
                 if (ret)
                         return ret;
 
@@ -143,6 +150,12 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 
 /**
  * iio_buffer_poll() - poll the buffer to find out if it has data
+ * @filp:       File structure pointer for device access
+ * @wait:       Poll table structure pointer for which the driver adds
+ *              a wait queue
+ *
+ * Return: (POLLIN | POLLRDNORM) if data is available for reading
+ *         or 0 for other cases
  */
 unsigned int iio_buffer_poll(struct file *filp,
                              struct poll_table_struct *wait)
@@ -151,7 +164,7 @@ unsigned int iio_buffer_poll(struct file *filp,
         struct iio_buffer *rb = indio_dev->buffer;
 
         if (!indio_dev->info)
-                return -ENODEV;
+                return 0;
 
         poll_wait(filp, &rb->pollq, wait);
         if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
@@ -1136,7 +1149,7 @@ int iio_scan_mask_query(struct iio_dev *indio_dev,
 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
 
 /**
- * struct iio_demux_table() - table describing demux memcpy ops
+ * struct iio_demux_table - table describing demux memcpy ops
  * @from:       index to copy from
  * @to:         index to copy to
  * @length:     how many bytes to copy