1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Fieldbus Device Driver Core
  4 *
  5 */
  6
  7#ifndef __FIELDBUS_DEV_H
  8#define __FIELDBUS_DEV_H
  9
 10#include <linux/cdev.h>
 11#include <linux/wait.h>
 12
 13enum fieldbus_dev_type {
 14	FIELDBUS_DEV_TYPE_UNKNOWN = 0,
 15	FIELDBUS_DEV_TYPE_PROFINET,
 16};
 17
 18enum fieldbus_dev_offl_mode {
 19	FIELDBUS_DEV_OFFL_MODE_CLEAR = 0,
 20	FIELDBUS_DEV_OFFL_MODE_FREEZE,
 21	FIELDBUS_DEV_OFFL_MODE_SET
 22};
 23
 24/**
 25 * struct fieldbus_dev - Fieldbus device
 26 * @read_area:		[DRIVER] function to read the process data area of the
 27 *				 device. same parameters/return values as
 28 *				 the read function in struct file_operations
 29 * @write_area:		[DRIVER] function to write to the process data area of
 30 *				 the device. same parameters/return values as
 31 *				 the write function in struct file_operations
 32 * @write_area_sz	[DRIVER] size of the writable process data area
 33 * @read_area_sz	[DRIVER] size of the readable process data area
 34 * @card_name		[DRIVER] name of the card, e.g. "ACME Inc. profinet"
 35 * @fieldbus_type	[DRIVER] fieldbus type of this device, e.g.
 36 *					FIELDBUS_DEV_TYPE_PROFINET
 37 * @enable_get		[DRIVER] function which returns true if the card
 38 *				 is enabled, false otherwise
 39 * @fieldbus_id_get	[DRIVER] function to retrieve the unique fieldbus id
 40 *				 by which this device can be identified;
 41 *				 return value follows the snprintf convention
 42 * @simple_enable_set	[DRIVER] (optional) function to enable the device
 43 *				 according to its default settings
 44 * @parent		[DRIVER] (optional) the device's parent device
 45 */
 46struct fieldbus_dev {
 47	ssize_t (*read_area)(struct fieldbus_dev *fbdev, char __user *buf,
 48			     size_t size, loff_t *offset);
 49	ssize_t (*write_area)(struct fieldbus_dev *fbdev,
 50			      const char __user *buf, size_t size,
 51			      loff_t *offset);
 52	size_t write_area_sz, read_area_sz;
 53	const char *card_name;
 54	enum fieldbus_dev_type fieldbus_type;
 55	bool (*enable_get)(struct fieldbus_dev *fbdev);
 56	int (*fieldbus_id_get)(struct fieldbus_dev *fbdev, char *buf,
 57			       size_t max_size);
 58	int (*simple_enable_set)(struct fieldbus_dev *fbdev, bool enable);
 59	struct device *parent;
 60
 61	/* private data */
 62	int id;
 63	struct cdev cdev;
 64	struct device *dev;
 65	int dc_event;
 66	wait_queue_head_t dc_wq;
 67	bool online;
 68};
 69
 70#if IS_ENABLED(CONFIG_FIELDBUS_DEV)
 71
 72/**
 73 * fieldbus_dev_unregister()
 74 *	- unregister a previously registered fieldbus device
 75 * @fb:		Device structure previously registered
 76 **/
 77void fieldbus_dev_unregister(struct fieldbus_dev *fb);
 78
 79/**
 80 * fieldbus_dev_register()
 81 *	- register a device with the fieldbus device subsystem
 82 * @fb:		Device structure filled by the device driver
 83 **/
 84int __must_check fieldbus_dev_register(struct fieldbus_dev *fb);
 85
 86/**
 87 * fieldbus_dev_area_updated()
 88 *	- notify the subsystem that an external fieldbus controller updated
 89 *			the process data area
 90 * @fb:		Device structure
 91 **/
 92void fieldbus_dev_area_updated(struct fieldbus_dev *fb);
 93
 94/**
 95 * fieldbus_dev_online_changed()
 96 *	- notify the subsystem that the fieldbus online status changed
 97 * @fb:		Device structure
 98 **/
 99void fieldbus_dev_online_changed(struct fieldbus_dev *fb, bool online);
100
101#else /* IS_ENABLED(CONFIG_FIELDBUS_DEV) */
102
103static inline void fieldbus_dev_unregister(struct fieldbus_dev *fb) {}
104static inline int __must_check fieldbus_dev_register(struct fieldbus_dev *fb)
105{
106	return -ENOTSUPP;
107}
108
109static inline void fieldbus_dev_area_updated(struct fieldbus_dev *fb) {}
110static inline void fieldbus_dev_online_changed(struct fieldbus_dev *fb,
111					       bool online) {}
112
113#endif /* IS_ENABLED(CONFIG_FIELDBUS_DEV) */
114#endif /* __FIELDBUS_DEV_H */