/*
 * PTP 1588 clock support
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifndef _PTP_CLOCK_KERNEL_H_
#define _PTP_CLOCK_KERNEL_H_

#include <linux/device.h>
#include <linux/pps_kernel.h>
#include <linux/ptp_clock.h>


struct ptp_clock_request {
        enum {
                PTP_CLK_REQ_EXTTS,
                PTP_CLK_REQ_PEROUT,
                PTP_CLK_REQ_PPS,
        } type;
        union {
                struct ptp_extts_request extts;
                struct ptp_perout_request perout;
        };
};

struct system_device_crosststamp;

/**
 * struct ptp_system_timestamp - system time corresponding to a PHC timestamp
 */
struct ptp_system_timestamp {
        struct timespec64 pre_ts;
        struct timespec64 post_ts;
};

/**
 * struct ptp_clock_info - decribes a PTP hardware clock
 *
 * @owner:     The clock driver should set to THIS_MODULE.
 * @name:      A short "friendly name" to identify the clock and to
 *             help distinguish PHY based devices from MAC based ones.
 *             The string is not meant to be a unique id.
 * @max_adj:   The maximum possible frequency adjustment, in parts per billon.
 * @n_alarm:   The number of programmable alarms.
 * @n_ext_ts:  The number of external time stamp channels.
 * @n_per_out: The number of programmable periodic signals.
 * @n_pins:    The number of programmable pins.
 * @pps:       Indicates whether the clock supports a PPS callback.
 * @pin_config: Array of length 'n_pins'. If the number of
 *              programmable pins is nonzero, then drivers must
 *              allocate and initialize this array.
 *
 * clock operations
 *
 * @adjfine:  Adjusts the frequency of the hardware clock.
 *            parameter scaled_ppm: Desired frequency offset from
 *            nominal frequency in parts per million, but with a
 *            16 bit binary fractional field.
 *
 * @adjfreq:  Adjusts the frequency of the hardware clock.
 *            This method is deprecated.  New drivers should implement
 *            the @adjfine method instead.
 *            parameter delta: Desired frequency offset from nominal frequency
 *            in parts per billion
 *
 * @adjtime:  Shifts the time of the hardware clock.
 *            parameter delta: Desired change in nanoseconds.
 *
 * @gettime64:  Reads the current time from the hardware clock.
 *              This method is deprecated.  New drivers should implement
 *              the @gettimex64 method instead.
 *              parameter ts: Holds the result.
 *
 * @gettimex64:  Reads the current time from the hardware clock and optionally
 *               also the system clock.
 *               parameter ts: Holds the PHC timestamp.
 *               parameter sts: If not NULL, it holds a pair of timestamps from
 *               the system clock. The first reading is made right before
 *               reading the lowest bits of the PHC timestamp and the second
 *               reading immediately follows that.
 *
 * @getcrosststamp:  Reads the current time from the hardware clock and
 *                   system clock simultaneously.
 *                   parameter cts: Contains timestamp (device,system) pair,
 *                   where system time is realtime and monotonic.
 *
 * @settime64:  Set the current time on the hardware clock.
 *              parameter ts: Time value to set.
 *
 * @enable:   Request driver to enable or disable an ancillary feature.
 *            parameter request: Desired resource to enable or disable.
 *            parameter on: Caller passes one to enable or zero to disable.
 *
 * @verify:   Confirm that a pin can perform a given function. The PTP
 *            Hardware Clock subsystem maintains the 'pin_config'
 *            array on behalf of the drivers, but the PHC subsystem
 *            assumes that every pin can perform every function. This
 *            hook gives drivers a way of telling the core about
 *            limitations on specific pins. This function must return
 *            zero if the function can be assigned to this pin, and
 *            nonzero otherwise.
 *            parameter pin: index of the pin in question.
 *            parameter func: the desired function to use.
 *            parameter chan: the function channel index to use.
 *
 * @do_work:  Request driver to perform auxiliary (periodic) operations
 *            Driver should return delay of the next auxiliary work scheduling
 *            time (>=0) or negative value in case further scheduling
 *            is not required.
 *
 * Drivers should embed their ptp_clock_info within a private
 * structure, obtaining a reference to it using container_of().
 *
 * The callbacks must all return zero on success, non-zero otherwise.
 */

struct ptp_clock_info {
        struct module *owner;
        char name[16];
        s32 max_adj;
        int n_alarm;
        int n_ext_ts;
        int n_per_out;
        int n_pins;
        int pps;
        struct ptp_pin_desc *pin_config;
        int (*adjfine)(struct ptp_clock_info *ptp, long scaled_ppm);
        int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
        int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
        int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
        int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
                          struct ptp_system_timestamp *sts);
        int (*getcrosststamp)(struct ptp_clock_info *ptp,
                              struct system_device_crosststamp *cts);
        int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
        int (*enable)(struct ptp_clock_info *ptp,
                      struct ptp_clock_request *request, int on);
        int (*verify)(struct ptp_clock_info *ptp, unsigned int pin,
                      enum ptp_pin_function func, unsigned int chan);
        long (*do_aux_work)(struct ptp_clock_info *ptp);
};

struct ptp_clock;

enum ptp_clock_events {
        PTP_CLOCK_ALARM,
        PTP_CLOCK_EXTTS,
        PTP_CLOCK_PPS,
        PTP_CLOCK_PPSUSR,
};

/**
 * struct ptp_clock_event - decribes a PTP hardware clock event
 *
 * @type:  One of the ptp_clock_events enumeration values.
 * @index: Identifies the source of the event.
 * @timestamp: When the event occurred (%PTP_CLOCK_EXTTS only).
 * @pps_times: When the event occurred (%PTP_CLOCK_PPSUSR only).
 */

struct ptp_clock_event {
        int type;
        int index;
        union {
                u64 timestamp;
                struct pps_event_time pps_times;
        };
};

#if IS_REACHABLE(CONFIG_PTP_1588_CLOCK)

/**
 * ptp_clock_register() - register a PTP hardware clock driver
 *
 * @info:   Structure describing the new clock.
 * @parent: Pointer to the parent device of the new clock.
 *
 * Returns a valid pointer on success or PTR_ERR on failure.  If PHC
 * support is missing at the configuration level, this function
 * returns NULL, and drivers are expected to gracefully handle that
 * case separately.
 */

extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
                                            struct device *parent);

/**
 * ptp_clock_unregister() - unregister a PTP hardware clock driver
 *
 * @ptp:  The clock to remove from service.
 */

extern int ptp_clock_unregister(struct ptp_clock *ptp);

/**
 * ptp_clock_event() - notify the PTP layer about an event
 *
 * @ptp:    The clock obtained from ptp_clock_register().
 * @event:  Message structure describing the event.
 */

extern void ptp_clock_event(struct ptp_clock *ptp,
                            struct ptp_clock_event *event);

/**
 * ptp_clock_index() - obtain the device index of a PTP clock
 *
 * @ptp:    The clock obtained from ptp_clock_register().
 */

extern int ptp_clock_index(struct ptp_clock *ptp);

/**
 * ptp_find_pin() - obtain the pin index of a given auxiliary function
 *
 * @ptp:    The clock obtained from ptp_clock_register().
 * @func:   One of the ptp_pin_function enumerated values.
 * @chan:   The particular functional channel to find.
 * Return:  Pin index in the range of zero to ptp_clock_caps.n_pins - 1,
 *          or -1 if the auxiliary function cannot be found.
 */

int ptp_find_pin(struct ptp_clock *ptp,
                 enum ptp_pin_function func, unsigned int chan);

/**
 * ptp_schedule_worker() - schedule ptp auxiliary work
 *
 * @ptp:    The clock obtained from ptp_clock_register().
 * @delay:  number of jiffies to wait before queuing
 *          See kthread_queue_delayed_work() for more info.
 */

int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay);

#else
static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
                                                   struct device *parent)
{ return NULL; }
static inline int ptp_clock_unregister(struct ptp_clock *ptp)
{ return 0; }
static inline void ptp_clock_event(struct ptp_clock *ptp,
                                   struct ptp_clock_event *event)
{ }
static inline int ptp_clock_index(struct ptp_clock *ptp)
{ return -1; }
static inline int ptp_find_pin(struct ptp_clock *ptp,
                               enum ptp_pin_function func, unsigned int chan)
{ return -1; }
static inline int ptp_schedule_worker(struct ptp_clock *ptp,
                                      unsigned long delay)
{ return -EOPNOTSUPP; }

#endif

static inline void ptp_read_system_prets(struct ptp_system_timestamp *sts)
{
        if (sts)
                ktime_get_real_ts64(&sts->pre_ts);
}

static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts)
{
        if (sts)
                ktime_get_real_ts64(&sts->post_ts);
}

#endif