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 <linux/iio/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); 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 * @buffer_list: [INTERN] entry in the devices list of current buffers. 70 */ 71 struct iio_buffer { 72 int length; 73 int bytes_per_datum; 74 struct attribute_group *scan_el_attrs; 75 long *scan_mask; 76 bool scan_timestamp; 77 const struct iio_buffer_access_funcs *access; 78 struct list_head scan_el_dev_attr_list; 79 struct attribute_group scan_el_group; 80 wait_queue_head_t pollq; 81 bool stufftoread; 82 const struct attribute_group *attrs; 83 struct list_head demux_list; 84 unsigned char *demux_bounce; 85 struct list_head buffer_list; 86 }; 87 88 /** 89 * iio_update_buffers() - add or remove buffer from active list 90 * @indio_dev: device to add buffer to 91 * @insert_buffer: buffer to insert 92 * @remove_buffer: buffer_to_remove 93 * 94 * Note this will tear down the all buffering and build it up again 95 */ 96 int iio_update_buffers(struct iio_dev *indio_dev, 97 struct iio_buffer *insert_buffer, 98 struct iio_buffer *remove_buffer); 99 100 /** 101 * iio_buffer_init() - Initialize the buffer structure 102 * @buffer: buffer to be initialized 103 **/ 104 void iio_buffer_init(struct iio_buffer *buffer); 105 106 /** 107 * __iio_update_buffer() - update common elements of buffers 108 * @buffer: buffer that is the event source 109 * @bytes_per_datum: size of individual datum including timestamp 110 * @length: number of datums in buffer 111 **/ 112 static inline void __iio_update_buffer(struct iio_buffer *buffer, 113 int bytes_per_datum, int length) 114 { 115 buffer->bytes_per_datum = bytes_per_datum; 116 buffer->length = length; 117 } 118 119 int iio_scan_mask_query(struct iio_dev *indio_dev, 120 struct iio_buffer *buffer, int bit); 121 122 /** 123 * iio_scan_mask_set() - set particular bit in the scan mask 124 * @indio_dev IIO device structure 125 * @buffer: the buffer whose scan mask we are interested in 126 * @bit: the bit to be set. 127 **/ 128 int iio_scan_mask_set(struct iio_dev *indio_dev, 129 struct iio_buffer *buffer, int bit); 130 131 /** 132 * iio_push_to_buffers() - push to a registered buffer. 133 * @indio_dev: iio_dev structure for device. 134 * @data: Full scan. 135 */ 136 int iio_push_to_buffers(struct iio_dev *indio_dev, unsigned char *data); 137 138 int iio_update_demux(struct iio_dev *indio_dev); 139 140 /** 141 * iio_buffer_register() - register the buffer with IIO core 142 * @indio_dev: device with the buffer to be registered 143 * @channels: the channel descriptions used to construct buffer 144 * @num_channels: the number of channels 145 **/ 146 int iio_buffer_register(struct iio_dev *indio_dev, 147 const struct iio_chan_spec *channels, 148 int num_channels); 149 150 /** 151 * iio_buffer_unregister() - unregister the buffer from IIO core 152 * @indio_dev: the device with the buffer to be unregistered 153 **/ 154 void iio_buffer_unregister(struct iio_dev *indio_dev); 155 156 /** 157 * iio_buffer_read_length() - attr func to get number of datums in the buffer 158 **/ 159 ssize_t iio_buffer_read_length(struct device *dev, 160 struct device_attribute *attr, 161 char *buf); 162 /** 163 * iio_buffer_write_length() - attr func to set number of datums in the buffer 164 **/ 165 ssize_t iio_buffer_write_length(struct device *dev, 166 struct device_attribute *attr, 167 const char *buf, 168 size_t len); 169 /** 170 * iio_buffer_store_enable() - attr to turn the buffer on 171 **/ 172 ssize_t iio_buffer_store_enable(struct device *dev, 173 struct device_attribute *attr, 174 const char *buf, 175 size_t len); 176 /** 177 * iio_buffer_show_enable() - attr to see if the buffer is on 178 **/ 179 ssize_t iio_buffer_show_enable(struct device *dev, 180 struct device_attribute *attr, 181 char *buf); 182 #define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \ 183 iio_buffer_read_length, \ 184 iio_buffer_write_length) 185 186 #define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \ 187 iio_buffer_show_enable, \ 188 iio_buffer_store_enable) 189 190 int iio_sw_buffer_preenable(struct iio_dev *indio_dev); 191 192 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev, 193 const unsigned long *mask); 194 195 #else /* CONFIG_IIO_BUFFER */ 196 197 static inline int iio_buffer_register(struct iio_dev *indio_dev, 198 const struct iio_chan_spec *channels, 199 int num_channels) 200 { 201 return 0; 202 } 203 204 static inline void iio_buffer_unregister(struct iio_dev *indio_dev) 205 {} 206 207 #endif /* CONFIG_IIO_BUFFER */ 208 209 #endif /* _IIO_BUFFER_GENERIC_H_ */ 210