1 files changed, 180 insertions, 0 deletions
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
new file mode 100644
index 000000000..eb8622b78
--- /dev/null
+++ b/include/linux/iio/buffer.h
@@ -0,0 +1,180 @@
+/* The industrial I/O core - generic buffer interfaces.
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#ifndef _IIO_BUFFER_GENERIC_H_
+#define _IIO_BUFFER_GENERIC_H_
+#include <linux/sysfs.h>
+#include <linux/iio/iio.h>
+#include <linux/kref.h>
+
+#ifdef CONFIG_IIO_BUFFER
+
+struct iio_buffer;
+
+/**
+ * struct iio_buffer_access_funcs - access functions for buffers.
+ * @store_to:		actually store stuff to the buffer
+ * @read_first_n:	try to get a specified number of bytes (must exist)
+ * @data_available:	indicates how much data is available for reading from
+ *			the buffer.
+ * @request_update:	if a parameter change has been marked, update underlying
+ *			storage.
+ * @set_bytes_per_datum:set number of bytes per datum
+ * @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.
+ *
+ * The purpose of this structure is to make the buffer element
+ * modular as event for a given driver, different usecases may require
+ * different buffer designs (space efficiency vs speed for example).
+ *
+ * It is worth noting that a given buffer implementation may only support a
+ * small proportion of these functions.  The core code 'should' cope fine with
+ * any of them not existing.
+ **/
+struct iio_buffer_access_funcs {
+	int (*store_to)(struct iio_buffer *buffer, const void *data);
+	int (*read_first_n)(struct iio_buffer *buffer,
+			    size_t n,
+			    char __user *buf);
+	size_t (*data_available)(struct iio_buffer *buffer);
+
+	int (*request_update)(struct iio_buffer *buffer);
+
+	int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
+	int (*set_length)(struct iio_buffer *buffer, int length);
+
+	void (*release)(struct iio_buffer *buffer);
+};
+
+/**
+ * struct iio_buffer - general buffer structure
+ * @length:		[DEVICE] number of datums in buffer
+ * @bytes_per_datum:	[DEVICE] size of individual datum including timestamp
+ * @scan_el_attrs:	[DRIVER] control of scan elements if that scan mode
+ *			control method is used
+ * @scan_mask:		[INTERN] bitmask used in masking scan mode elements
+ * @scan_timestamp:	[INTERN] does the scan mode include a timestamp
+ * @access:		[DRIVER] buffer access functions associated with the
+ *			implementation.
+ * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
+ * @scan_el_group:	[DRIVER] attribute group for those attributes not
+ *			created from the iio_chan_info array.
+ * @pollq:		[INTERN] wait queue to allow for polling on the buffer.
+ * @stufftoread:	[INTERN] flag to indicate new data.
+ * @demux_list:		[INTERN] list of operations required to demux the scan.
+ * @demux_bounce:	[INTERN] buffer for doing gather from incoming scan.
+ * @buffer_list:	[INTERN] entry in the devices list of current buffers.
+ * @ref:		[INTERN] reference count of the buffer.
+ * @watermark:		[INTERN] number of datums to wait for poll/read.
+ */
+struct iio_buffer {
+	int					length;
+	int					bytes_per_datum;
+	struct attribute_group			*scan_el_attrs;
+	long					*scan_mask;
+	bool					scan_timestamp;
+	const struct iio_buffer_access_funcs	*access;
+	struct list_head			scan_el_dev_attr_list;
+	struct attribute_group			buffer_group;
+	struct attribute_group			scan_el_group;
+	wait_queue_head_t			pollq;
+	bool					stufftoread;
+	const struct attribute			**attrs;
+	struct list_head			demux_list;
+	void					*demux_bounce;
+	struct list_head			buffer_list;
+	struct kref				ref;
+	unsigned int				watermark;
+};
+
+/**
+ * iio_update_buffers() - add or remove buffer from active list
+ * @indio_dev:		device to add buffer to
+ * @insert_buffer:	buffer to insert
+ * @remove_buffer:	buffer_to_remove
+ *
+ * Note this will tear down the all buffering and build it up again
+ */
+int iio_update_buffers(struct iio_dev *indio_dev,
+		       struct iio_buffer *insert_buffer,
+		       struct iio_buffer *remove_buffer);
+
+/**
+ * iio_buffer_init() - Initialize the buffer structure
+ * @buffer:		buffer to be initialized
+ **/
+void iio_buffer_init(struct iio_buffer *buffer);
+
+int iio_scan_mask_query(struct iio_dev *indio_dev,
+			struct iio_buffer *buffer, int bit);
+
+/**
+ * iio_push_to_buffers() - push to a registered buffer.
+ * @indio_dev:		iio_dev structure for device.
+ * @data:		Full scan.
+ */
+int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data);
+
+/*
+ * iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers
+ * @indio_dev:		iio_dev structure for device.
+ * @data:		sample data
+ * @timestamp:		timestamp for the sample data
+ *
+ * Pushes data to the IIO device's buffers. If timestamps are enabled for the
+ * device the function will store the supplied timestamp as the last element in
+ * the sample data buffer before pushing it to the device buffers. The sample
+ * data buffer needs to be large enough to hold the additional timestamp
+ * (usually the buffer should be indio->scan_bytes bytes large).
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ */
+static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev,
+	void *data, int64_t timestamp)
+{
+	if (indio_dev->scan_timestamp) {
+		size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1;
+		((int64_t *)data)[ts_offset] = timestamp;
+	}
+
+	return iio_push_to_buffers(indio_dev, data);
+}
+
+int iio_update_demux(struct iio_dev *indio_dev);
+
+bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
+	const unsigned long *mask);
+
+struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer);
+void iio_buffer_put(struct iio_buffer *buffer);
+
+/**
+ * iio_device_attach_buffer - Attach a buffer to a IIO device
+ * @indio_dev: The device the buffer should be attached to
+ * @buffer: The buffer to attach to the device
+ *
+ * This function attaches a buffer to a IIO device. The buffer stays attached to
+ * the device until the device is freed. The function should only be called at
+ * most once per device.
+ */
+static inline void iio_device_attach_buffer(struct iio_dev *indio_dev,
+	struct iio_buffer *buffer)
+{
+	indio_dev->buffer = iio_buffer_get(buffer);
+}
+
+#else /* CONFIG_IIO_BUFFER */
+
+static inline void iio_buffer_get(struct iio_buffer *buffer) {}
+static inline void iio_buffer_put(struct iio_buffer *buffer) {}
+
+#endif /* CONFIG_IIO_BUFFER */
+
+#endif /* _IIO_BUFFER_GENERIC_H_ */