1 #ifndef _IIO_BUFFER_GENERIC_IMPL_H_ 2 #define _IIO_BUFFER_GENERIC_IMPL_H_ 3 #include <linux/sysfs.h> 4 #include <linux/kref.h> 5 6 #ifdef CONFIG_IIO_BUFFER 7 8 struct iio_dev; 9 struct iio_buffer; 10 11 /** 12 * INDIO_BUFFER_FLAG_FIXED_WATERMARK - Watermark level of the buffer can not be 13 * configured. It has a fixed value which will be buffer specific. 14 */ 15 #define INDIO_BUFFER_FLAG_FIXED_WATERMARK BIT(0) 16 17 /** 18 * struct iio_buffer_access_funcs - access functions for buffers. 19 * @store_to: actually store stuff to the buffer 20 * @read_first_n: try to get a specified number of bytes (must exist) 21 * @data_available: indicates how much data is available for reading from 22 * the buffer. 23 * @request_update: if a parameter change has been marked, update underlying 24 * storage. 25 * @set_bytes_per_datum:set number of bytes per datum 26 * @set_length: set number of datums in buffer 27 * @enable: called if the buffer is attached to a device and the 28 * device starts sampling. Calls are balanced with 29 * @disable. 30 * @disable: called if the buffer is attached to a device and the 31 * device stops sampling. Calles are balanced with @enable. 32 * @release: called when the last reference to the buffer is dropped, 33 * should free all resources allocated by the buffer. 34 * @modes: Supported operating modes by this buffer type 35 * @flags: A bitmask combination of INDIO_BUFFER_FLAG_* 36 * 37 * The purpose of this structure is to make the buffer element 38 * modular as event for a given driver, different usecases may require 39 * different buffer designs (space efficiency vs speed for example). 40 * 41 * It is worth noting that a given buffer implementation may only support a 42 * small proportion of these functions. The core code 'should' cope fine with 43 * any of them not existing. 44 **/ 45 struct iio_buffer_access_funcs { 46 int (*store_to)(struct iio_buffer *buffer, const void *data); 47 int (*read_first_n)(struct iio_buffer *buffer, 48 size_t n, 49 char __user *buf); 50 size_t (*data_available)(struct iio_buffer *buffer); 51 52 int (*request_update)(struct iio_buffer *buffer); 53 54 int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd); 55 int (*set_length)(struct iio_buffer *buffer, int length); 56 57 int (*enable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); 58 int (*disable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); 59 60 void (*release)(struct iio_buffer *buffer); 61 62 unsigned int modes; 63 unsigned int flags; 64 }; 65 66 /** 67 * struct iio_buffer - general buffer structure 68 * 69 * Note that the internals of this structure should only be of interest to 70 * those writing new buffer implementations. 71 */ 72 struct iio_buffer { 73 /** @length: Number of datums in buffer. */ 74 int length; 75 76 /** @bytes_per_datum: Size of individual datum including timestamp. */ 77 int bytes_per_datum; 78 79 /** 80 * @access: Buffer access functions associated with the 81 * implementation. 82 */ 83 const struct iio_buffer_access_funcs *access; 84 85 /** @scan_mask: Bitmask used in masking scan mode elements. */ 86 long *scan_mask; 87 88 /** @demux_list: List of operations required to demux the scan. */ 89 struct list_head demux_list; 90 91 /** @pollq: Wait queue to allow for polling on the buffer. */ 92 wait_queue_head_t pollq; 93 94 /** @watermark: Number of datums to wait for poll/read. */ 95 unsigned int watermark; 96 97 /* private: */ 98 /* 99 * @scan_el_attrs: Control of scan elements if that scan mode 100 * control method is used. 101 */ 102 struct attribute_group *scan_el_attrs; 103 104 /* @scan_timestamp: Does the scan mode include a timestamp. */ 105 bool scan_timestamp; 106 107 /* @scan_el_dev_attr_list: List of scan element related attributes. */ 108 struct list_head scan_el_dev_attr_list; 109 110 /* @buffer_group: Attributes of the buffer group. */ 111 struct attribute_group buffer_group; 112 113 /* 114 * @scan_el_group: Attribute group for those attributes not 115 * created from the iio_chan_info array. 116 */ 117 struct attribute_group scan_el_group; 118 119 /* @stufftoread: Flag to indicate new data. */ 120 bool stufftoread; 121 122 /* @attrs: Standard attributes of the buffer. */ 123 const struct attribute **attrs; 124 125 /* @demux_bounce: Buffer for doing gather from incoming scan. */ 126 void *demux_bounce; 127 128 /* @buffer_list: Entry in the devices list of current buffers. */ 129 struct list_head buffer_list; 130 131 /* @ref: Reference count of the buffer. */ 132 struct kref ref; 133 }; 134 135 /** 136 * iio_update_buffers() - add or remove buffer from active list 137 * @indio_dev: device to add buffer to 138 * @insert_buffer: buffer to insert 139 * @remove_buffer: buffer_to_remove 140 * 141 * Note this will tear down the all buffering and build it up again 142 */ 143 int iio_update_buffers(struct iio_dev *indio_dev, 144 struct iio_buffer *insert_buffer, 145 struct iio_buffer *remove_buffer); 146 147 /** 148 * iio_buffer_init() - Initialize the buffer structure 149 * @buffer: buffer to be initialized 150 **/ 151 void iio_buffer_init(struct iio_buffer *buffer); 152 153 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer); 154 void iio_buffer_put(struct iio_buffer *buffer); 155 156 #else /* CONFIG_IIO_BUFFER */ 157 158 static inline void iio_buffer_get(struct iio_buffer *buffer) {} 159 static inline void iio_buffer_put(struct iio_buffer *buffer) {} 160 161 #endif /* CONFIG_IIO_BUFFER */ 162 #endif /* _IIO_BUFFER_GENERIC_IMPL_H_ */ 163