iio: buffer: Allocate standard attributes in the core

All buffers want at least the length and the enable attribute. Move the
creation of those attributes to the core instead of having to do this in
each individual buffer implementation. This allows us to get rid of some
boiler-plate code.

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

3 files changed, 43 insertions, 45 deletions

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 8cd89eb269c5..ba89357fc096 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -383,9 +383,9 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
 	return ret;
 }
 
-ssize_t iio_buffer_read_length(struct device *dev,
-			       struct device_attribute *attr,
-			       char *buf)
+static ssize_t iio_buffer_read_length(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct iio_buffer *buffer = indio_dev->buffer;
@@ -396,12 +396,10 @@ ssize_t iio_buffer_read_length(struct device *dev,
 
 	return 0;
 }
-EXPORT_SYMBOL(iio_buffer_read_length);
 
-ssize_t iio_buffer_write_length(struct device *dev,
-				struct device_attribute *attr,
-				const char *buf,
-				size_t len)
+static ssize_t iio_buffer_write_length(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t len)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct iio_buffer *buffer = indio_dev->buffer;
@@ -428,16 +426,14 @@ ssize_t iio_buffer_write_length(struct device *dev,
 
 	return ret ? ret : len;
 }
-EXPORT_SYMBOL(iio_buffer_write_length);
 
-ssize_t iio_buffer_show_enable(struct device *dev,
-			       struct device_attribute *attr,
-			       char *buf)
+static ssize_t iio_buffer_show_enable(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
 }
-EXPORT_SYMBOL(iio_buffer_show_enable);
 
 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
 				const unsigned long *mask, bool timestamp)
@@ -724,10 +720,10 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(iio_update_buffers);
 
-ssize_t iio_buffer_store_enable(struct device *dev,
-				struct device_attribute *attr,
-				const char *buf,
-				size_t len)
+static ssize_t iio_buffer_store_enable(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf,
+				       size_t len)
 {
 	int ret;
 	bool requested_state;
@@ -759,10 +755,14 @@ done:
 	mutex_unlock(&indio_dev->mlock);
 	return (ret < 0) ? ret : len;
 }
-EXPORT_SYMBOL(iio_buffer_store_enable);
 
 static const char * const iio_scan_elements_group_name = "scan_elements";
 
+static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
+		   iio_buffer_write_length);
+static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
+		   iio_buffer_show_enable, iio_buffer_store_enable);
+
 int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
 {
 	struct iio_dev_attr *p;
@@ -774,6 +774,27 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
 	if (!buffer)
 		return 0;
 
+	attrcount = 0;
+	if (buffer->attrs) {
+		while (buffer->attrs[attrcount] != NULL)
+			attrcount++;
+	}
+
+	buffer->buffer_group.name = "buffer";
+	buffer->buffer_group.attrs = kcalloc(attrcount + 3,
+			sizeof(*buffer->buffer_group.attrs), GFP_KERNEL);
+	if (!buffer->buffer_group.attrs)
+		return -ENOMEM;
+
+	buffer->buffer_group.attrs[0] = &dev_attr_length.attr;
+	buffer->buffer_group.attrs[1] = &dev_attr_enable.attr;
+	if (buffer->attrs)
+		memcpy(&buffer->buffer_group.attrs[2], buffer->attrs,
+			sizeof(*&buffer->buffer_group.attrs) * (attrcount - 2));
+	buffer->buffer_group.attrs[attrcount+2] = NULL;
+
+	indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
+
 	if (buffer->scan_el_attrs != NULL) {
 		attr = buffer->scan_el_attrs->attrs;
 		while (*attr++ != NULL)
@@ -838,6 +859,7 @@ error_free_scan_mask:
 	kfree(buffer->scan_mask);
 error_cleanup_dynamic:
 	iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
+	kfree(indio_dev->buffer->buffer_group.attrs);
 
 	return ret;
 }
@@ -848,6 +870,7 @@ void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
 		return;
 
 	kfree(indio_dev->buffer->scan_mask);
+	kfree(indio_dev->buffer->buffer_group.attrs);
 	kfree(indio_dev->buffer->scan_el_group.attrs);
 	iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
 }
diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
index 1258b4e0a722..3b0a3bc4f0ad 100644
--- a/drivers/iio/kfifo_buf.c
+++ b/drivers/iio/kfifo_buf.c
@@ -52,20 +52,6 @@ static int iio_get_length_kfifo(struct iio_buffer *r)
 	return r->length;
 }
 
-static IIO_BUFFER_ENABLE_ATTR;
-static IIO_BUFFER_LENGTH_ATTR;
-
-static struct attribute *iio_kfifo_attributes[] = {
-	&dev_attr_length.attr,
-	&dev_attr_enable.attr,
-	NULL,
-};
-
-static struct attribute_group iio_kfifo_attribute_group = {
-	.attrs = iio_kfifo_attributes,
-	.name = "buffer",
-};
-
 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
 {
 	struct iio_kfifo *kf = iio_to_kfifo(r);
@@ -169,7 +155,6 @@ struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
 		return NULL;
 	kf->update_needed = true;
 	iio_buffer_init(&kf->buffer);
-	kf->buffer.attrs = &iio_kfifo_attribute_group;
 	kf->buffer.access = &kfifo_access_funcs;
 	kf->buffer.length = 2;
 	mutex_init(&kf->user_lock);
diff --git a/drivers/staging/iio/accel/sca3000_ring.c b/drivers/staging/iio/accel/sca3000_ring.c
index aa0e5d85bfe2..f2f260e01550 100644
--- a/drivers/staging/iio/accel/sca3000_ring.c
+++ b/drivers/staging/iio/accel/sca3000_ring.c
@@ -140,9 +140,6 @@ static bool sca3000_ring_buf_data_available(struct iio_buffer *r)
 	return r->stufftoread;
 }
 
-static IIO_BUFFER_ENABLE_ATTR;
-static IIO_BUFFER_LENGTH_ATTR;
-
 /**
  * sca3000_query_ring_int() is the hardware ring status interrupt enabled
  **/
@@ -232,20 +229,13 @@ static IIO_DEVICE_ATTR(in_accel_scale,
  * only apply to the ring buffer.  At all times full rate and accuracy
  * is available via direct reading from registers.
  */
-static struct attribute *sca3000_ring_attributes[] = {
-	&dev_attr_length.attr,
-	&dev_attr_enable.attr,
+static const struct attribute *sca3000_ring_attributes[] = {
 	&iio_dev_attr_50_percent.dev_attr.attr,
 	&iio_dev_attr_75_percent.dev_attr.attr,
 	&iio_dev_attr_in_accel_scale.dev_attr.attr,
 	NULL,
 };
 
-static struct attribute_group sca3000_ring_attr = {
-	.attrs = sca3000_ring_attributes,
-	.name = "buffer",
-};
-
 static struct iio_buffer *sca3000_rb_allocate(struct iio_dev *indio_dev)
 {
 	struct iio_buffer *buf;
@@ -258,7 +248,7 @@ static struct iio_buffer *sca3000_rb_allocate(struct iio_dev *indio_dev)
 	ring->private = indio_dev;
 	buf = &ring->buf;
 	buf->stufftoread = 0;
-	buf->attrs = &sca3000_ring_attr;
+	buf->attrs = sca3000_ring_attributes;
 	iio_buffer_init(buf);
 
 	return buf;