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>

1 files changed, 41 insertions, 18 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);
 }