| 1 | /* The industrial I/O core - generic buffer interfaces. |
| 2 | * |
| 3 | * Copyright (c) 2008 Jonathan Cameron |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 as published by |
| 7 | * the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #ifndef _IIO_BUFFER_GENERIC_H_ |
| 11 | #define _IIO_BUFFER_GENERIC_H_ |
| 12 | #include <linux/sysfs.h> |
| 13 | #include "iio.h" |
| 14 | |
| 15 | #ifdef CONFIG_IIO_BUFFER |
| 16 | |
| 17 | struct iio_buffer; |
| 18 | |
| 19 | /** |
| 20 | * struct iio_buffer_access_funcs - access functions for buffers. |
| 21 | * @store_to: actually store stuff to the buffer |
| 22 | * @read_first_n: try to get a specified number of bytes (must exist) |
| 23 | * @request_update: if a parameter change has been marked, update underlying |
| 24 | * storage. |
| 25 | * @get_bytes_per_datum:get current bytes per datum |
| 26 | * @set_bytes_per_datum:set number of bytes per datum |
| 27 | * @get_length: get number of datums in buffer |
| 28 | * @set_length: set number of datums in buffer |
| 29 | * |
| 30 | * The purpose of this structure is to make the buffer element |
| 31 | * modular as event for a given driver, different usecases may require |
| 32 | * different buffer designs (space efficiency vs speed for example). |
| 33 | * |
| 34 | * It is worth noting that a given buffer implementation may only support a |
| 35 | * small proportion of these functions. The core code 'should' cope fine with |
| 36 | * any of them not existing. |
| 37 | **/ |
| 38 | struct iio_buffer_access_funcs { |
| 39 | int (*store_to)(struct iio_buffer *buffer, u8 *data, s64 timestamp); |
| 40 | int (*read_first_n)(struct iio_buffer *buffer, |
| 41 | size_t n, |
| 42 | char __user *buf); |
| 43 | |
| 44 | int (*request_update)(struct iio_buffer *buffer); |
| 45 | |
| 46 | int (*get_bytes_per_datum)(struct iio_buffer *buffer); |
| 47 | int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd); |
| 48 | int (*get_length)(struct iio_buffer *buffer); |
| 49 | int (*set_length)(struct iio_buffer *buffer, int length); |
| 50 | }; |
| 51 | |
| 52 | /** |
| 53 | * struct iio_buffer - general buffer structure |
| 54 | * @length: [DEVICE] number of datums in buffer |
| 55 | * @bytes_per_datum: [DEVICE] size of individual datum including timestamp |
| 56 | * @scan_el_attrs: [DRIVER] control of scan elements if that scan mode |
| 57 | * control method is used |
| 58 | * @scan_mask: [INTERN] bitmask used in masking scan mode elements |
| 59 | * @scan_timestamp: [INTERN] does the scan mode include a timestamp |
| 60 | * @access: [DRIVER] buffer access functions associated with the |
| 61 | * implementation. |
| 62 | * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes. |
| 63 | * @scan_el_group: [DRIVER] attribute group for those attributes not |
| 64 | * created from the iio_chan_info array. |
| 65 | * @pollq: [INTERN] wait queue to allow for polling on the buffer. |
| 66 | * @stufftoread: [INTERN] flag to indicate new data. |
| 67 | * @demux_list: [INTERN] list of operations required to demux the scan. |
| 68 | * @demux_bounce: [INTERN] buffer for doing gather from incoming scan. |
| 69 | **/ |
| 70 | struct iio_buffer { |
| 71 | int length; |
| 72 | int bytes_per_datum; |
| 73 | struct attribute_group *scan_el_attrs; |
| 74 | long *scan_mask; |
| 75 | bool scan_timestamp; |
| 76 | const struct iio_buffer_access_funcs *access; |
| 77 | struct list_head scan_el_dev_attr_list; |
| 78 | struct attribute_group scan_el_group; |
| 79 | wait_queue_head_t pollq; |
| 80 | bool stufftoread; |
| 81 | const struct attribute_group *attrs; |
| 82 | struct list_head demux_list; |
| 83 | unsigned char *demux_bounce; |
| 84 | }; |
| 85 | |
| 86 | /** |
| 87 | * iio_buffer_init() - Initialize the buffer structure |
| 88 | * @buffer: buffer to be initialized |
| 89 | **/ |
| 90 | void iio_buffer_init(struct iio_buffer *buffer); |
| 91 | |
| 92 | /** |
| 93 | * __iio_update_buffer() - update common elements of buffers |
| 94 | * @buffer: buffer that is the event source |
| 95 | * @bytes_per_datum: size of individual datum including timestamp |
| 96 | * @length: number of datums in buffer |
| 97 | **/ |
| 98 | static inline void __iio_update_buffer(struct iio_buffer *buffer, |
| 99 | int bytes_per_datum, int length) |
| 100 | { |
| 101 | buffer->bytes_per_datum = bytes_per_datum; |
| 102 | buffer->length = length; |
| 103 | } |
| 104 | |
| 105 | int iio_scan_mask_query(struct iio_dev *indio_dev, |
| 106 | struct iio_buffer *buffer, int bit); |
| 107 | |
| 108 | /** |
| 109 | * iio_scan_mask_set() - set particular bit in the scan mask |
| 110 | * @buffer: the buffer whose scan mask we are interested in |
| 111 | * @bit: the bit to be set. |
| 112 | **/ |
| 113 | int iio_scan_mask_set(struct iio_dev *indio_dev, |
| 114 | struct iio_buffer *buffer, int bit); |
| 115 | |
| 116 | /** |
| 117 | * iio_push_to_buffer() - push to a registered buffer. |
| 118 | * @buffer: IIO buffer structure for device |
| 119 | * @scan: Full scan. |
| 120 | * @timestamp: |
| 121 | */ |
| 122 | int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data, |
| 123 | s64 timestamp); |
| 124 | |
| 125 | int iio_update_demux(struct iio_dev *indio_dev); |
| 126 | |
| 127 | /** |
| 128 | * iio_buffer_register() - register the buffer with IIO core |
| 129 | * @indio_dev: device with the buffer to be registered |
| 130 | **/ |
| 131 | int iio_buffer_register(struct iio_dev *indio_dev, |
| 132 | const struct iio_chan_spec *channels, |
| 133 | int num_channels); |
| 134 | |
| 135 | /** |
| 136 | * iio_buffer_unregister() - unregister the buffer from IIO core |
| 137 | * @indio_dev: the device with the buffer to be unregistered |
| 138 | **/ |
| 139 | void iio_buffer_unregister(struct iio_dev *indio_dev); |
| 140 | |
| 141 | /** |
| 142 | * iio_buffer_read_length() - attr func to get number of datums in the buffer |
| 143 | **/ |
| 144 | ssize_t iio_buffer_read_length(struct device *dev, |
| 145 | struct device_attribute *attr, |
| 146 | char *buf); |
| 147 | /** |
| 148 | * iio_buffer_write_length() - attr func to set number of datums in the buffer |
| 149 | **/ |
| 150 | ssize_t iio_buffer_write_length(struct device *dev, |
| 151 | struct device_attribute *attr, |
| 152 | const char *buf, |
| 153 | size_t len); |
| 154 | /** |
| 155 | * iio_buffer_store_enable() - attr to turn the buffer on |
| 156 | **/ |
| 157 | ssize_t iio_buffer_store_enable(struct device *dev, |
| 158 | struct device_attribute *attr, |
| 159 | const char *buf, |
| 160 | size_t len); |
| 161 | /** |
| 162 | * iio_buffer_show_enable() - attr to see if the buffer is on |
| 163 | **/ |
| 164 | ssize_t iio_buffer_show_enable(struct device *dev, |
| 165 | struct device_attribute *attr, |
| 166 | char *buf); |
| 167 | #define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \ |
| 168 | iio_buffer_read_length, \ |
| 169 | iio_buffer_write_length) |
| 170 | |
| 171 | #define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \ |
| 172 | iio_buffer_show_enable, \ |
| 173 | iio_buffer_store_enable) |
| 174 | |
| 175 | int iio_sw_buffer_preenable(struct iio_dev *indio_dev); |
| 176 | |
| 177 | #else /* CONFIG_IIO_BUFFER */ |
| 178 | |
| 179 | static inline int iio_buffer_register(struct iio_dev *indio_dev, |
| 180 | struct iio_chan_spec *channels, |
| 181 | int num_channels) |
| 182 | { |
| 183 | return 0; |
| 184 | } |
| 185 | |
| 186 | static inline void iio_buffer_unregister(struct iio_dev *indio_dev) |
| 187 | {}; |
| 188 | |
| 189 | #endif /* CONFIG_IIO_BUFFER */ |
| 190 | |
| 191 | #endif /* _IIO_BUFFER_GENERIC_H_ */ |