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Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
-rw-r--r--drivers/iio/industrialio-buffer.c35
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