diff options
Diffstat (limited to 'include/linux/iio/buffer.h')
| -rw-r--r-- | include/linux/iio/buffer.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h new file mode 100644 index 000000000000..fb0fe46fd659 --- /dev/null +++ b/include/linux/iio/buffer.h @@ -0,0 +1,191 @@ +/* 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_ */ |