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-rw-r--r--include/linux/iio/buffer.h191
1 files changed, 191 insertions, 0 deletions
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
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+++ b/include/linux/iio/buffer.h
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+/* 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>
+
+#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)
+ * @request_update: if a parameter change has been marked, update underlying
+ * storage.
+ * @get_bytes_per_datum:get current bytes per datum
+ * @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
+ *
+ * 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, u8 *data, s64 timestamp);
+ int (*read_first_n)(struct iio_buffer *buffer,
+ size_t n,
+ char __user *buf);
+
+ int (*request_update)(struct iio_buffer *buffer);
+
+ int (*get_bytes_per_datum)(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);
+};
+
+/**
+ * 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.
+ **/
+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 scan_el_group;
+ wait_queue_head_t pollq;
+ bool stufftoread;
+ const struct attribute_group *attrs;
+ struct list_head demux_list;
+ unsigned char *demux_bounce;
+};
+
+/**
+ * iio_buffer_init() - Initialize the buffer structure
+ * @buffer: buffer to be initialized
+ **/
+void iio_buffer_init(struct iio_buffer *buffer);
+
+/**
+ * __iio_update_buffer() - update common elements of buffers
+ * @buffer: buffer that is the event source
+ * @bytes_per_datum: size of individual datum including timestamp
+ * @length: number of datums in buffer
+ **/
+static inline void __iio_update_buffer(struct iio_buffer *buffer,
+ int bytes_per_datum, int length)
+{
+ buffer->bytes_per_datum = bytes_per_datum;
+ buffer->length = length;
+}
+
+int iio_scan_mask_query(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer, int bit);
+
+/**
+ * iio_scan_mask_set() - set particular bit in the scan mask
+ * @buffer: the buffer whose scan mask we are interested in
+ * @bit: the bit to be set.
+ **/
+int iio_scan_mask_set(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer, int bit);
+
+/**
+ * iio_push_to_buffer() - push to a registered buffer.
+ * @buffer: IIO buffer structure for device
+ * @scan: Full scan.
+ * @timestamp:
+ */
+int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
+ s64 timestamp);
+
+int iio_update_demux(struct iio_dev *indio_dev);
+
+/**
+ * iio_buffer_register() - register the buffer with IIO core
+ * @indio_dev: device with the buffer to be registered
+ **/
+int iio_buffer_register(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *channels,
+ int num_channels);
+
+/**
+ * iio_buffer_unregister() - unregister the buffer from IIO core
+ * @indio_dev: the device with the buffer to be unregistered
+ **/
+void iio_buffer_unregister(struct iio_dev *indio_dev);
+
+/**
+ * iio_buffer_read_length() - attr func to get number of datums in the buffer
+ **/
+ssize_t iio_buffer_read_length(struct device *dev,
+ struct device_attribute *attr,
+ char *buf);
+/**
+ * iio_buffer_write_length() - attr func to set number of datums in the buffer
+ **/
+ssize_t iio_buffer_write_length(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t len);
+/**
+ * iio_buffer_store_enable() - attr to turn the buffer on
+ **/
+ssize_t iio_buffer_store_enable(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t len);
+/**
+ * iio_buffer_show_enable() - attr to see if the buffer is on
+ **/
+ssize_t iio_buffer_show_enable(struct device *dev,
+ struct device_attribute *attr,
+ char *buf);
+#define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
+ iio_buffer_read_length, \
+ iio_buffer_write_length)
+
+#define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
+ iio_buffer_show_enable, \
+ iio_buffer_store_enable)
+
+int iio_sw_buffer_preenable(struct iio_dev *indio_dev);
+
+#else /* CONFIG_IIO_BUFFER */
+
+static inline int iio_buffer_register(struct iio_dev *indio_dev,
+ struct iio_chan_spec *channels,
+ int num_channels)
+{
+ return 0;
+}
+
+static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
+{};
+
+#endif /* CONFIG_IIO_BUFFER */
+
+#endif /* _IIO_BUFFER_GENERIC_H_ */