iio: buffer: Drop get_length callback

We already do have the length field in the struct iio_buffer which is
expected to be in sync with the current size of the buffer. And currently
all implementations of the get_length callback either return this field or a
constant number.

This patch removes the get_length callback and replaces all occurrences in
the IIO core with directly accessing the length field of the buffer.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

5 files changed, 6 insertions, 25 deletions

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 4ca4c0a09923..2bd8d399f2ec 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -390,11 +390,7 @@ static ssize_t iio_buffer_read_length(struct device *dev,
         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
         struct iio_buffer *buffer = indio_dev->buffer;
 
-        if (buffer->access->get_length)
-                return sprintf(buf, "%d\n",
-                               buffer->access->get_length(buffer));
-
-        return 0;
+        return sprintf(buf, "%d\n", buffer->length);
 }
 
 static ssize_t iio_buffer_write_length(struct device *dev,
@@ -410,9 +406,8 @@ static ssize_t iio_buffer_write_length(struct device *dev,
         if (ret)
                 return ret;
 
-        if (buffer->access->get_length)
-                if (val == buffer->access->get_length(buffer))
-                        return len;
+        if (val == buffer->length)
+                return len;
 
         mutex_lock(&indio_dev->mlock);
         if (iio_buffer_is_active(indio_dev->buffer)) {
diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
index 3b0a3bc4f0ad..b20a9cfbc8ed 100644
--- a/drivers/iio/kfifo_buf.c
+++ b/drivers/iio/kfifo_buf.c
@@ -47,11 +47,6 @@ static int iio_request_update_kfifo(struct iio_buffer *r)
         return ret;
 }
 
-static int iio_get_length_kfifo(struct iio_buffer *r)
-{
-        return r->length;
-}
-
 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
 {
         struct iio_kfifo *kf = iio_to_kfifo(r);
@@ -141,7 +136,6 @@ static const struct iio_buffer_access_funcs kfifo_access_funcs = {
         .data_available = iio_kfifo_buf_data_available,
         .request_update = &iio_request_update_kfifo,
         .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
-        .get_length = &iio_get_length_kfifo,
         .set_length = &iio_set_length_kfifo,
         .release = &iio_kfifo_buffer_release,
 };
diff --git a/drivers/staging/iio/Documentation/ring.txt b/drivers/staging/iio/Documentation/ring.txt
index 434d63a6123a..18718fcaf259 100644
--- a/drivers/staging/iio/Documentation/ring.txt
+++ b/drivers/staging/iio/Documentation/ring.txt
@@ -42,6 +42,6 @@ request_update
 set_bytes_per_datum
   Set the number of bytes for a complete scan. (All samples + timestamp)
 
-get_length / set_length
-  Get/set the number of complete scans that may be held by the buffer.
+set_length
+  Set the number of complete scans that may be held by the buffer.
 
diff --git a/drivers/staging/iio/accel/sca3000_ring.c b/drivers/staging/iio/accel/sca3000_ring.c
index f2f260e01550..f76a26885808 100644
--- a/drivers/staging/iio/accel/sca3000_ring.c
+++ b/drivers/staging/iio/accel/sca3000_ring.c
@@ -129,12 +129,6 @@ error_ret:
         return ret ? ret : num_read;
 }
 
-/* This is only valid with all 3 elements enabled */
-static int sca3000_ring_get_length(struct iio_buffer *r)
-{
-        return 64;
-}
-
 static bool sca3000_ring_buf_data_available(struct iio_buffer *r)
 {
         return r->stufftoread;
@@ -248,6 +242,7 @@ static struct iio_buffer *sca3000_rb_allocate(struct iio_dev *indio_dev)
         ring->private = indio_dev;
         buf = &ring->buf;
         buf->stufftoread = 0;
+        buf->length = 64;
         buf->attrs = sca3000_ring_attributes;
         iio_buffer_init(buf);
 
@@ -261,7 +256,6 @@ static void sca3000_ring_release(struct iio_buffer *r)
 
 static const struct iio_buffer_access_funcs sca3000_ring_access_funcs = {
         .read_first_n = &sca3000_read_first_n_hw_rb,
-        .get_length = &sca3000_ring_get_length,
         .data_available = sca3000_ring_buf_data_available,
         .release = sca3000_ring_release,
 };
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index 16b7663036f2..b65850a41127 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -26,7 +26,6 @@ struct iio_buffer;
  * @request_update:     if a parameter change has been marked, update underlying
  *                      storage.
  * @set_bytes_per_datum:set number of bytes per datum
- * @get_length:         get number of datums in buffer
  * @set_length:         set number of datums in buffer
  * @release:            called when the last reference to the buffer is dropped,
  *                      should free all resources allocated by the buffer.
@@ -49,7 +48,6 @@ struct iio_buffer_access_funcs {
         int (*request_update)(struct iio_buffer *buffer);
 
         int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
-        int (*get_length)(struct iio_buffer *buffer);
         int (*set_length)(struct iio_buffer *buffer, int length);
 
         void (*release)(struct iio_buffer *buffer);