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Diffstat (limited to 'drivers/staging/iio/ring_generic.h')
| -rw-r--r-- | drivers/staging/iio/ring_generic.h | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/drivers/staging/iio/ring_generic.h b/drivers/staging/iio/ring_generic.h new file mode 100644 index 000000000000..d9261897f332 --- /dev/null +++ b/drivers/staging/iio/ring_generic.h @@ -0,0 +1,283 @@ +/* The industrial I/O core - generic ring 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_RING_GENERIC_H_ +#define _IIO_RING_GENERIC_H_ +#include "iio.h" + +struct iio_handler; +struct iio_ring_buffer; +struct iio_dev; + +/** + * iio_push_ring_event() - ring buffer specific push to event chrdev + * @ring_buf: ring buffer that is the event source + * @event_code: event indentification code + * @timestamp: time of event + **/ +int iio_push_ring_event(struct iio_ring_buffer *ring_buf, + int event_code, + s64 timestamp); +/** + * iio_push_or_escallate_ring_event() - escallate or add as appropriate + * + * Typical usecase is to escallate a 50% ring full to 75% full if noone has yet + * read the first event. Clearly the 50% full is no longer of interest in + * typical use case. + **/ +int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf, + int event_code, + s64 timestamp); + +/** + * struct iio_ring_access_funcs - access functions for ring buffers. + * @create: perform allocation + * @init: get ring buffer ready for use + * @_exit: reverse steps in init + * @_free: deallocate ring buffer + * @mark_in_use: reference counting, typically to prevent module removal + * @unmark_in_use: reduce reference count when no longer using ring buffer + * @store_to: actually store stuff to the ring buffer + * @read_last: get the last element stored + * @rip_lots: try to get a specified number of elements (must exist) + * @mark_param_change: notify ring that some relevant parameter has changed + * Often this means the underlying storage may need to + * change. + * @request_update: if a parameter change has been marked, update underlying + * storage. + * @get_bpd: get current bytes per datum + * @set_bpd: set number of bytes per datum + * @get_length: get number of datums in ring + * @set_length: set number of datums in ring + * @is_enabled: query if ring is currently being used + * @enable: enable the ring + * + * The purpose of this structure is to make the ring buffer element + * modular as event for a given driver, different usecases may require + * different ring designs (space efficiency vs speed for example. + * + * It is worth noting that a given ring implementation may only support a small + * proportion of these functions. The core code 'should' cope fine with any of + * them not existing. + **/ +struct iio_ring_access_funcs { + void (*mark_in_use)(struct iio_ring_buffer *ring); + void (*unmark_in_use)(struct iio_ring_buffer *ring); + + int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp); + int (*read_last)(struct iio_ring_buffer *ring, u8 *data); + int (*rip_lots)(struct iio_ring_buffer *ring, + size_t count, + u8 **data, + int *dead_offset); + + int (*mark_param_change)(struct iio_ring_buffer *ring); + int (*request_update)(struct iio_ring_buffer *ring); + + int (*get_bpd)(struct iio_ring_buffer *ring); + int (*set_bpd)(struct iio_ring_buffer *ring, size_t bpd); + int (*get_length)(struct iio_ring_buffer *ring); + int (*set_length)(struct iio_ring_buffer *ring, int length); + + int (*is_enabled)(struct iio_ring_buffer *ring); + int (*enable)(struct iio_ring_buffer *ring); +}; + +/** + * struct iio_ring_buffer - general ring buffer structure + * @length: [DEVICE]number of datums in ring + * @bpd: [DEVICE]size of individual datum including timestamp + * @loopcount: [INTERN]number of times the ring has looped + * @access_minor_name: [INTERN]store of name of the access chrdev minor number + * sysfs attribute + * @access_handler: [INTERN]chrdev access handling + * @event_minor_name: [INTERN]store of name of the event chrdev minor number + * sysfs attribute + * @ev_int: [INTERN]chrdev interface for the event chrdev + * @shared_ev_pointer: [INTERN]the shared event pointer to allow escalation of + * events + * @ring_access: [DRIVER]ring access functions associated with the + * implementation. + * @ring_prenable: [DRIVER] function to run prior to marking ring enabled + * @ring_postenable: [DRIVER] function to run after marking ring enabled + * @ring_predisable: [DRIVER] function to run prior to marking ring disabled + * @ring_postdisable: [DRIVER] function to run after marking ring disabled + **/ +struct iio_ring_buffer { + struct device dev; + struct device access_dev; + struct iio_dev *indio_dev; + struct module *owner; + int id; + int access_id; + int length; + int bpd; + int loopcount; + struct iio_handler access_handler; + struct iio_event_interface ev_int; + struct iio_shared_ev_pointer shared_ev_pointer; + struct iio_ring_access_funcs access; + int (*preenable)(struct iio_dev *); + int (*postenable)(struct iio_dev *); + int (*predisable)(struct iio_dev *); + int (*postdisable)(struct iio_dev *); + +}; +void iio_ring_buffer_init(struct iio_ring_buffer *ring, + struct iio_dev *dev_info); + +/** + * __iio_init_ring_buffer() - initialize common elements of ring buffers. + **/ +static inline void __iio_init_ring_buffer(struct iio_ring_buffer *ring, + int bytes_per_datum, int length) +{ + ring->bpd = bytes_per_datum; + ring->length = length; + ring->loopcount = 0; + ring->shared_ev_pointer.ev_p = 0; + ring->shared_ev_pointer.lock = + __SPIN_LOCK_UNLOCKED(ring->shared_ev_pointer->loc); +} + +/** + * struct iio_scan_el - an individual element of a scan + * @dev_attr: control attribute (if directly controllable) + * @number: unique identifier of element (used for bit mask) + * @bit_count: number of bits in scan element + * @label: useful data for the scan el (often reg address) + * @set_state: for some devices datardy signals are generated + * for any enabled lines. This allows unwanted lines + * to be disabled and hence not get in the way. + **/ +struct iio_scan_el { + struct device_attribute dev_attr; + unsigned int number; + int bit_count; + unsigned int label; + + int (*set_state)(struct iio_scan_el *scanel, + struct iio_dev *dev_info, + bool state); +}; + +#define to_iio_scan_el(_dev_attr) \ + container_of(_dev_attr, struct iio_scan_el, dev_attr); + +/** + * iio_scan_el_store() - sysfs scan element selection interface. + * + * A generic function used to enable various scan elements. In some + * devices explicit read commands for each channel mean this is merely + * a software switch. In others this must actively disable the channel. + * Complexities occur when this interacts with data ready type triggers + * which may not reset unless every channel that is enabled is explicitly + * read. + **/ +ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len); +/** + * iio_scal_el_show() - sysfs interface to query whether a scan element is + * is enabled or not. + **/ +ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr, + char *buf); +/** + * IIO_SCAN_EL: - declare and initialize a scan element without control func + * @_name: identifying name. Resulting struct is iio_scan_el_##_name, + * sysfs element, scan_en_##_name. + * @_number: unique id number for the scan element. + * @_bits: number of bits in the scan element result (used in mixed bit + * length devices). + * @_label: indentification variable used by drivers. Often a reg address. + **/ +#define IIO_SCAN_EL(_name, _number, _bits, _label) \ + struct iio_scan_el iio_scan_el_##_name = { \ + .dev_attr = __ATTR(scan_en_##_name, \ + S_IRUGO | S_IWUSR, \ + iio_scan_el_show, \ + iio_scan_el_store), \ + .mask = (1 << _number), \ + .bit_count = _bits, \ + .label = _label, \ + } + +ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len); + +ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr, + char *buf); +/** + * IIO_SCAN_EL_C: - declare and initialize a scan element with a control func + * + * @_controlfunc: function used to notify hardware of whether state changes + **/ +#define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \ + struct iio_scan_el iio_scan_el_##_name = { \ + .dev_attr = __ATTR(scan_en_##_name, \ + S_IRUGO | S_IWUSR, \ + iio_scan_el_show, \ + iio_scan_el_store), \ + .number = _number, \ + .bit_count = _bits, \ + .label = _label, \ + .set_state = _controlfunc, \ + } +/** + * IIO_SCAN_EL_TIMESTAMP: - declare a special scan element for timestamps + * + * Odd one out. Handled slightly differently from other scan elements. + **/ +#define IIO_SCAN_EL_TIMESTAMP \ + struct iio_scan_el iio_scan_el_timestamp = { \ + .dev_attr = __ATTR(scan_en_timestamp, \ + S_IRUGO | S_IWUSR, \ + iio_scan_el_ts_show, \ + iio_scan_el_ts_store), \ + } + +static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring) +{ + put_device(&ring->dev); +}; + +#define to_iio_ring_buffer(d) \ + container_of(d, struct iio_ring_buffer, dev) +#define access_dev_to_iio_ring_buffer(d) \ + container_of(d, struct iio_ring_buffer, access_dev) +int iio_ring_buffer_register(struct iio_ring_buffer *ring); +void iio_ring_buffer_unregister(struct iio_ring_buffer *ring); + +ssize_t iio_read_ring_length(struct device *dev, + struct device_attribute *attr, + char *buf); +ssize_t iio_write_ring_length(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len); +ssize_t iio_read_ring_bps(struct device *dev, + struct device_attribute *attr, + char *buf); +ssize_t iio_store_ring_enable(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len); +ssize_t iio_show_ring_enable(struct device *dev, + struct device_attribute *attr, + char *buf); +#define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \ + iio_read_ring_length, \ + iio_write_ring_length) +#define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR, \ + iio_read_ring_bps, NULL) +#define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \ + iio_show_ring_enable, \ + iio_store_ring_enable) + +#endif /* _IIO_RING_GENERIC_H_ */ |