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 int iio_scan_mask_query(struct iio_dev *indio_dev, 107 struct iio_buffer *buffer, int bit); 108 109 /** 110 * iio_scan_mask_set() - set particular bit in the scan mask 111 * @indio_dev IIO device structure 112 * @buffer: the buffer whose scan mask we are interested in 113 * @bit: the bit to be set. 114 **/ 115 int iio_scan_mask_set(struct iio_dev *indio_dev, 116 struct iio_buffer *buffer, int bit); 117 118 /** 119 * iio_push_to_buffers() - push to a registered buffer. 120 * @indio_dev: iio_dev structure for device. 121 * @data: Full scan. 122 */ 123 int iio_push_to_buffers(struct iio_dev *indio_dev, unsigned char *data); 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 * @channels: the channel descriptions used to construct buffer 131 * @num_channels: the number of channels 132 **/ 133 int iio_buffer_register(struct iio_dev *indio_dev, 134 const struct iio_chan_spec *channels, 135 int num_channels); 136 137 /** 138 * iio_buffer_unregister() - unregister the buffer from IIO core 139 * @indio_dev: the device with the buffer to be unregistered 140 **/ 141 void iio_buffer_unregister(struct iio_dev *indio_dev); 142 143 /** 144 * iio_buffer_read_length() - attr func to get number of datums in the buffer 145 **/ 146 ssize_t iio_buffer_read_length(struct device *dev, 147 struct device_attribute *attr, 148 char *buf); 149 /** 150 * iio_buffer_write_length() - attr func to set number of datums in the buffer 151 **/ 152 ssize_t iio_buffer_write_length(struct device *dev, 153 struct device_attribute *attr, 154 const char *buf, 155 size_t len); 156 /** 157 * iio_buffer_store_enable() - attr to turn the buffer on 158 **/ 159 ssize_t iio_buffer_store_enable(struct device *dev, 160 struct device_attribute *attr, 161 const char *buf, 162 size_t len); 163 /** 164 * iio_buffer_show_enable() - attr to see if the buffer is on 165 **/ 166 ssize_t iio_buffer_show_enable(struct device *dev, 167 struct device_attribute *attr, 168 char *buf); 169 #define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \ 170 iio_buffer_read_length, \ 171 iio_buffer_write_length) 172 173 #define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \ 174 iio_buffer_show_enable, \ 175 iio_buffer_store_enable) 176 177 int iio_sw_buffer_preenable(struct iio_dev *indio_dev); 178 179 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev, 180 const unsigned long *mask); 181 182 #else /* CONFIG_IIO_BUFFER */ 183 184 static inline int iio_buffer_register(struct iio_dev *indio_dev, 185 const struct iio_chan_spec *channels, 186 int num_channels) 187 { 188 return 0; 189 } 190 191 static inline void iio_buffer_unregister(struct iio_dev *indio_dev) 192 {} 193 194 #endif /* CONFIG_IIO_BUFFER */ 195 196 #endif /* _IIO_BUFFER_GENERIC_H_ */ 197