Merge tag 'mfd-for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd

[karo-tx-linux.git] / drivers / iio / industrialio-buffer.c

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 6eee1b044c60ed5806494d95bfa69a83687103a6..d7e908acb48020b3f5390030e5a3687b03ba9878 100644 (file)
--- 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