/* The industrial I/O core
 *
 * 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 _INDUSTRIAL_IO_H_
#define _INDUSTRIAL_IO_H_

#include <linux/device.h>
#include <linux/cdev.h>
#include "sysfs.h"
#include "chrdev.h"

/* IIO TODO LIST */
/* Static device specific elements (conversion factors etc)
 * should be exported via sysfs
 *
 * Provide means of adjusting timer accuracy.
 * Currently assumes nano seconds.
 */

/* Event interface flags */
#define IIO_BUSY_BIT_POS 1

struct iio_dev;

/**
 * iio_get_time_ns() - utility function to get a time stamp for events etc
 **/
static inline s64 iio_get_time_ns(void)
{
        struct timespec ts;
        /*
         * calls getnstimeofday.
         * If hrtimers then up to ns accurate, if not microsecond.
         */
        ktime_get_real_ts(&ts);

        return timespec_to_ns(&ts);
}

/**
 * iio_add_event_to_list() - Wraps adding to event lists
 * @el:         the list element of the event to be handled.
 * @head:       the list associated with the event handler being used.
 *
 * Does reference counting to allow shared handlers.
 **/
void iio_add_event_to_list(struct iio_event_handler_list *el,
                           struct list_head *head);

/**
 * iio_remove_event_from_list() - Wraps removing from event list
 * @el:         element to be removed
 * @head:       associate list head for the interrupt handler.
 *
 * Does reference counting to allow shared handlers.
 **/
void iio_remove_event_from_list(struct iio_event_handler_list *el,
                                struct list_head *head);

/* Device operating modes */
#define INDIO_DIRECT_MODE               0x01
#define INDIO_RING_TRIGGERED            0x02
#define INDIO_RING_HARDWARE_BUFFER      0x08

#define INDIO_ALL_RING_MODES (INDIO_RING_TRIGGERED | INDIO_RING_HARDWARE_BUFFER)

/* Vast majority of this is set by the industrialio subsystem on a
 * call to iio_device_register. */

/**
 * struct iio_dev - industrial I/O device
 * @id:                 [INTERN] used to identify device internally
 * @dev_data:           [DRIVER] device specific data
 * @modes:              [DRIVER] operating modes supported by device
 * @currentmode:        [DRIVER] current operating mode
 * @dev:                [DRIVER] device structure, should be assigned a parent
 *                      and owner
 * @attrs:              [DRIVER] general purpose device attributes
 * @driver_module:      [DRIVER] module structure used to ensure correct
 *                      ownership of chrdevs etc
 * @num_interrupt_lines:[DRIVER] number of physical interrupt lines from device
 * @interrupts:         [INTERN] interrupt line specific event lists etc
 * @event_attrs:        [DRIVER] event control attributes
 * @event_conf_attrs:   [DRIVER] event configuration attributes
 * @event_interfaces:   [INTERN] event chrdevs associated with interrupt lines
 * @ring:               [DRIVER] any ring buffer present
 * @mlock:              [INTERN] lock used to prevent simultaneous device state
 *                      changes
 * @scan_el_attrs:      [DRIVER] control of scan elements if that scan mode
 *                      control method is used
 * @scan_count: [INTERN] the number of elements in the current scan mode
 * @scan_mask:          [INTERN] bitmask used in masking scan mode elements
 * @scan_timestamp:     [INTERN] does the scan mode include a timestamp
 * @trig:               [INTERN] current device trigger (ring buffer modes)
 * @pollfunc:           [DRIVER] function run on trigger being recieved
 **/
struct iio_dev {
        int                             id;
        void                            *dev_data;
        int                             modes;
        int                             currentmode;
        struct device                   dev;
        const struct attribute_group    *attrs;
        struct module                   *driver_module;

        int                             num_interrupt_lines;
        struct iio_interrupt            **interrupts;
        struct attribute_group          *event_attrs;
        struct attribute_group          *event_conf_attrs;

        struct iio_event_interface      *event_interfaces;

        struct iio_ring_buffer          *ring;
        struct mutex                    mlock;

        struct attribute_group          *scan_el_attrs;
        int                             scan_count;

        u16                             scan_mask;
        bool                            scan_timestamp;
        struct iio_trigger              *trig;
        struct iio_poll_func            *pollfunc;
};

/*
 * These are mainly provided to allow for a change of implementation if a device
 * has a large number of scan elements
 */
#define IIO_MAX_SCAN_LENGTH 15

static inline int iio_scan_mask_query(struct iio_dev *dev_info, int bit)
{
        if (bit > IIO_MAX_SCAN_LENGTH)
                return -EINVAL;
        else
                return !!(dev_info->scan_mask & (1 << bit));
};

static inline int iio_scan_mask_set(struct iio_dev *dev_info, int bit)
{
        if (bit > IIO_MAX_SCAN_LENGTH)
                return -EINVAL;
        dev_info->scan_mask |= (1 << bit);
        dev_info->scan_count++;
        return 0;
};

static inline int iio_scan_mask_clear(struct iio_dev *dev_info, int bit)
{
        if (bit > IIO_MAX_SCAN_LENGTH)
                return -EINVAL;
        dev_info->scan_mask &= ~(1 << bit);
        dev_info->scan_count--;
        return 0;
};

/**
 * iio_scan_mask_count_to_right() - how many scan elements occur before here
 * @dev_info: the iio_device whose scan mode we are querying
 * @bit: which number scan element is this
 **/
static inline int iio_scan_mask_count_to_right(struct iio_dev *dev_info,
int bit)
{
        int count = 0;
        int mask = (1 << bit);
        if (bit > IIO_MAX_SCAN_LENGTH)
                return -EINVAL;
        while (mask) {
                mask >>= 1;
                if (mask & dev_info->scan_mask)
                        count++;
        }

        return count;
}

/**
 * iio_device_register() - register a device with the IIO subsystem
 * @dev_info:           Device structure filled by the device driver
 **/
int iio_device_register(struct iio_dev *dev_info);

/**
 * iio_device_unregister() - unregister a device from the IIO subsystem
 * @dev_info:           Device structure representing the device.
 **/
void iio_device_unregister(struct iio_dev *dev_info);

/**
 * struct iio_interrupt - wrapper used to allow easy handling of multiple
 *                      physical interrupt lines
 * @dev_info:           the iio device for which the is an interrupt line
 * @line_number:        associated line number
 * @id:                 idr allocated unique id number
 * @irq:                associate interrupt number
 * @ev_list:            event handler list for associated events
 * @ev_list_lock:       ensure only one access to list at a time
 **/
struct iio_interrupt {
        struct iio_dev                  *dev_info;
        int                             line_number;
        int                             id;
        int                             irq;
        struct list_head                ev_list;
        spinlock_t                      ev_list_lock;
};

#define to_iio_interrupt(i) container_of(i, struct iio_interrupt, ev_list)

/**
 * iio_register_interrupt_line() - Tell IIO about interrupt lines
 *
 * @irq:                Typically provided via platform data
 * @dev_info:           IIO device info structure for device
 * @line_number:        Which interrupt line of the device is this?
 * @type:               Interrupt type (e.g. edge triggered etc)
 * @name:               Identifying name.
 **/
int iio_register_interrupt_line(unsigned int                    irq,
                                struct iio_dev                  *dev_info,
                                int                             line_number,
                                unsigned long                   type,
                                const char                      *name);

void iio_unregister_interrupt_line(struct iio_dev *dev_info,
                                   int line_number);



/**
 * iio_push_event() - try to add event to the list for userspace reading
 * @dev_info:           IIO device structure
 * @ev_line:            Which event line (hardware interrupt)
 * @ev_code:            What event
 * @timestamp:          When the event occured
 **/
int iio_push_event(struct iio_dev *dev_info,
                  int ev_line,
                  int ev_code,
                  s64 timestamp);

/**
 * struct iio_work_cont - container for when singleton handler case matters
 * @ws:                 [DEVICE]work_struct when not only possible event
 * @ws_nocheck:         [DEVICE]work_struct when only possible event
 * @address:            [DEVICE]associated register address
 * @mask:               [DEVICE]associated mask for identifying event source
 * @st:                 [DEVICE]device specific state information
 **/
struct iio_work_cont {
        struct work_struct      ws;
        struct work_struct      ws_nocheck;
        int                     address;
        int                     mask;
        void                    *st;
};

#define to_iio_work_cont_check(_ws)                     \
        container_of(_ws, struct iio_work_cont, ws)

#define to_iio_work_cont_no_check(_ws)                          \
        container_of(_ws, struct iio_work_cont, ws_nocheck)

/**
 * iio_init_work_cont() - intiialize the elements of a work container
 * @cont: the work container
 * @_checkfunc: function called when there are multiple possible int sources
 * @_nocheckfunc: function for when there is only one int source
 * @_add: driver dependant, typically a register address
 * @_mask: driver dependant, typically a bit mask for a register
 * @_st: driver dependant, typically pointer to a device state structure
 **/
static inline void
iio_init_work_cont(struct iio_work_cont *cont,
                   void (*_checkfunc)(struct work_struct *),
                   void (*_nocheckfunc)(struct work_struct *),
                   int _add, int _mask, void *_st)
{
        INIT_WORK(&(cont)->ws, _checkfunc);
        INIT_WORK(&(cont)->ws_nocheck, _nocheckfunc);
        cont->address = _add;
        cont->mask = _mask;
        cont->st = _st;
}
/**
 * __iio_push_event() tries to add an event to the list associated with a chrdev
 * @ev_int:             the event interface to which we are pushing the event
 * @ev_code:            the outgoing event code
 * @timestamp:          timestamp of the event
 * @shared_pointer_p:   the shared event pointer
 **/
int __iio_push_event(struct iio_event_interface *ev_int,
                    int ev_code,
                    s64 timestamp,
                    struct iio_shared_ev_pointer*
                    shared_pointer_p);
/**
 * __iio_change_event() change an event code in case of event escallation
 * @ev:                 the evnet to be changed
 * @ev_code:            new event code
 * @timestamp:          new timestamp
 **/
void __iio_change_event(struct iio_detected_event_list *ev,
                        int ev_code,
                        s64 timestamp);

/**
 * iio_setup_ev_int() Configure an event interface (chrdev)
 * @name:               name used for resulting sysfs directory etc.
 * @ev_int:             interface we are configuring
 * @owner:              module that is responsible for registering this ev_int
 * @dev:                device whose ev_int this is
 **/
int iio_setup_ev_int(struct iio_event_interface *ev_int,
                     const char *name,
                     struct module *owner,
                     struct device *dev);

void iio_free_ev_int(struct iio_event_interface *ev_int);

/**
 * iio_allocate_chrdev() - Allocate a chrdev
 * @handler:    struct that contains relevant file handling for chrdev
 * @dev_info:   iio_dev for which chrdev is being created
 **/
int iio_allocate_chrdev(struct iio_handler *handler, struct iio_dev *dev_info);
void iio_deallocate_chrdev(struct iio_handler *handler);

/* Used to distinguish between bipolar and unipolar scan elemenents.
 * Whilst this may seem obvious, we may well want to change the representation
 * in the future!*/
#define IIO_SIGNED(a) -(a)
#define IIO_UNSIGNED(a) (a)

extern dev_t iio_devt;
extern struct class iio_class;

/**
 * iio_put_device() - reference counted deallocated of struct device
 * @dev: the iio_device containing the device
 **/
static inline void iio_put_device(struct iio_dev *dev)
{
        if (dev)
                put_device(&dev->dev);
};

/**
 * to_iio_dev() - get iio_dev for which we have have the struct device
 * @d: the struct device
 **/
static inline struct iio_dev *to_iio_dev(struct device *d)
{
        return container_of(d, struct iio_dev, dev);
};

/**
 * iio_dev_get_devdata() - helper function gets device specific data
 * @d: the iio_dev associated with the device
 **/
static inline void *iio_dev_get_devdata(struct iio_dev *d)
{
        return d->dev_data;
}

/**
 * iio_allocate_device() - allocate an iio_dev from a driver
 **/
struct iio_dev *iio_allocate_device(void);

/**
 * iio_free_device() - free an iio_dev from a driver
 **/
void iio_free_device(struct iio_dev *dev);

/**
 * iio_put() - internal module reference count reduce
 **/
void iio_put(void);

/**
 * iio_get() - internal module reference count increase
 **/
void iio_get(void);

/* Ring buffer related */
int iio_device_get_chrdev_minor(void);
void iio_device_free_chrdev_minor(int val);

/**
 * iio_ring_enabled() helper function to test if any form of ring enabled
 **/
static inline bool iio_ring_enabled(struct iio_dev *dev_info)
{
        return dev_info->currentmode
                & (INDIO_RING_TRIGGERED
                   | INDIO_RING_HARDWARE_BUFFER);
};

struct idr;

int iio_get_new_idr_val(struct idr *this_idr);
void iio_free_idr_val(struct idr *this_idr, int id);
#endif /* _INDUSTRIAL_IO_H_ */