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Diffstat (limited to 'kernel/include/linux/iio/buffer.h')
| -rw-r--r-- | kernel/include/linux/iio/buffer.h | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/kernel/include/linux/iio/buffer.h b/kernel/include/linux/iio/buffer.h new file mode 100644 index 000000000..eb8622b78 --- /dev/null +++ b/kernel/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_ */ |