// SPDX-License-Identifier: GPL-2.0

/* Texas Instruments ICSSG Industrial Ethernet Peripheral (IEP) Driver
 *
 * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com
 *
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/timekeeping.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/workqueue.h>

#include "icss_iep.h"

#define IEP_MAX_DEF_INC		0xf
#define IEP_MAX_COMPEN_INC		0xfff
#define IEP_MAX_COMPEN_COUNT	0xffffff

#define IEP_GLOBAL_CFG_CNT_ENABLE	BIT(0)
#define IEP_GLOBAL_CFG_DEFAULT_INC_MASK		GENMASK(7, 4)
#define IEP_GLOBAL_CFG_DEFAULT_INC_SHIFT	4
#define IEP_GLOBAL_CFG_COMPEN_INC_MASK		GENMASK(19, 8)
#define IEP_GLOBAL_CFG_COMPEN_INC_SHIFT		8

#define IEP_GLOBAL_STATUS_CNT_OVF	BIT(0)

#define IEP_CMP_CFG_SHADOW_EN		BIT(17)
#define IEP_CMP_CFG_CMP0_RST_CNT_EN	BIT(0)
#define IEP_CMP_CFG_CMP_EN(cmp)		(GENMASK(16, 1) & (1 << ((cmp) + 1)))

#define IEP_CMP_STATUS(cmp)		(1 << (cmp))

#define IEP_SYNC_CTRL_SYNC_EN		BIT(0)
#define IEP_SYNC_CTRL_SYNC_N_EN(n)	(GENMASK(2, 1) & (BIT(1) << (n)))

#define IEP_MIN_CMP	0
#define IEP_MAX_CMP	15

#define ICSS_IEP_64BIT_COUNTER_SUPPORT		BIT(0)
#define ICSS_IEP_SLOW_COMPEN_REG_SUPPORT	BIT(1)
#define ICSS_IEP_SHADOW_MODE_SUPPORT		BIT(2)

#define LATCH_INDEX(ts_index)			((ts_index) + 6)
#define IEP_CAP_CFG_CAPNR_1ST_EVENT_EN(n)	BIT(LATCH_INDEX(n))
#define IEP_CAP_CFG_CAP_ASYNC_EN(n)		BIT(LATCH_INDEX(n) + 10)

/**
 * icss_iep_get_count_hi() - Get the upper 32 bit IEP counter
 * @iep: Pointer to structure representing IEP.
 *
 * Return: upper 32 bit IEP counter
 */
int icss_iep_get_count_hi(struct icss_iep *iep)
{
	u32 val = 0;

	if (iep && (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT))
		val = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG1]);

	return val;
}
EXPORT_SYMBOL_GPL(icss_iep_get_count_hi);

/**
 * icss_iep_get_count_low() - Get the lower 32 bit IEP counter
 * @iep: Pointer to structure representing IEP.
 *
 * Return: lower 32 bit IEP counter
 */
int icss_iep_get_count_low(struct icss_iep *iep)
{
	u32 val = 0;

	if (iep)
		val = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]);

	return val;
}
EXPORT_SYMBOL_GPL(icss_iep_get_count_low);

/**
 * icss_iep_get_ptp_clock_idx() - Get PTP clock index using IEP driver
 * @iep: Pointer to structure representing IEP.
 *
 * Return: PTP clock index, -1 if not registered
 */
int icss_iep_get_ptp_clock_idx(struct icss_iep *iep)
{
	if (!iep || !iep->ptp_clock)
		return -1;
	return ptp_clock_index(iep->ptp_clock);
}
EXPORT_SYMBOL_GPL(icss_iep_get_ptp_clock_idx);

static void icss_iep_set_counter(struct icss_iep *iep, u64 ns)
{
	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
		writel(upper_32_bits(ns), iep->base +
		       iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG1]);
	writel(lower_32_bits(ns), iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]);
}

static void icss_iep_update_to_next_boundary(struct icss_iep *iep, u64 start_ns);

/**
 * icss_iep_settime() - Set time of the PTP clock using IEP driver
 * @iep: Pointer to structure representing IEP.
 * @ns: Time to be set in nanoseconds
 *
 * This API uses writel() instead of regmap_write() for write operations as
 * regmap_write() is too slow and this API is time sensitive.
 */
static void icss_iep_settime(struct icss_iep *iep, u64 ns)
{
	if (iep->ops && iep->ops->settime) {
		iep->ops->settime(iep->clockops_data, ns);
		return;
	}

	if (iep->pps_enabled || iep->perout_enabled)
		writel(0, iep->base + iep->plat_data->reg_offs[ICSS_IEP_SYNC_CTRL_REG]);

	icss_iep_set_counter(iep, ns);

	if (iep->pps_enabled || iep->perout_enabled) {
		icss_iep_update_to_next_boundary(iep, ns);
		writel(IEP_SYNC_CTRL_SYNC_N_EN(0) | IEP_SYNC_CTRL_SYNC_EN,
		       iep->base + iep->plat_data->reg_offs[ICSS_IEP_SYNC_CTRL_REG]);
	}
}

/**
 * icss_iep_gettime() - Get time of the PTP clock using IEP driver
 * @iep: Pointer to structure representing IEP.
 * @sts: Pointer to structure representing PTP system timestamp.
 *
 * This API uses readl() instead of regmap_read() for read operations as
 * regmap_read() is too slow and this API is time sensitive.
 *
 * Return: The current timestamp of the PTP clock using IEP driver
 */
static u64 icss_iep_gettime(struct icss_iep *iep,
			    struct ptp_system_timestamp *sts)
{
	u32 ts_hi = 0, ts_lo;
	unsigned long flags;

	if (iep->ops && iep->ops->gettime)
		return iep->ops->gettime(iep->clockops_data, sts);

	/* use local_irq_x() to make it work for both RT/non-RT */
	local_irq_save(flags);

	/* no need to play with hi-lo, hi is latched when lo is read */
	ptp_read_system_prets(sts);
	ts_lo = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]);
	ptp_read_system_postts(sts);
	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
		ts_hi = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG1]);

	local_irq_restore(flags);

	return (u64)ts_lo | (u64)ts_hi << 32;
}

static void icss_iep_enable(struct icss_iep *iep)
{
	regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_CFG_REG,
			   IEP_GLOBAL_CFG_CNT_ENABLE,
			   IEP_GLOBAL_CFG_CNT_ENABLE);
}

static void icss_iep_disable(struct icss_iep *iep)
{
	regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_CFG_REG,
			   IEP_GLOBAL_CFG_CNT_ENABLE,
			   0);
}

static void icss_iep_enable_shadow_mode(struct icss_iep *iep)
{
	u32 cycle_time;
	int cmp;

	cycle_time = iep->cycle_time_ns - iep->def_inc;

	icss_iep_disable(iep);

	/* disable shadow mode */
	regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
			   IEP_CMP_CFG_SHADOW_EN, 0);

	/* enable shadow mode */
	regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
			   IEP_CMP_CFG_SHADOW_EN, IEP_CMP_CFG_SHADOW_EN);

	/* clear counters */
	icss_iep_set_counter(iep, 0);

	/* clear overflow status */
	regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_STATUS_REG,
			   IEP_GLOBAL_STATUS_CNT_OVF,
			   IEP_GLOBAL_STATUS_CNT_OVF);

	/* clear compare status */
	for (cmp = IEP_MIN_CMP; cmp < IEP_MAX_CMP; cmp++) {
		regmap_update_bits(iep->map, ICSS_IEP_CMP_STAT_REG,
				   IEP_CMP_STATUS(cmp), IEP_CMP_STATUS(cmp));

		regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
				   IEP_CMP_CFG_CMP_EN(cmp), 0);
	}

	/* enable reset counter on CMP0 event */
	regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
			   IEP_CMP_CFG_CMP0_RST_CNT_EN,
			   IEP_CMP_CFG_CMP0_RST_CNT_EN);
	/* enable compare */
	regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
			   IEP_CMP_CFG_CMP_EN(0),
			   IEP_CMP_CFG_CMP_EN(0));

	/* set CMP0 value to cycle time */
	regmap_write(iep->map, ICSS_IEP_CMP0_REG0, cycle_time);
	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
		regmap_write(iep->map, ICSS_IEP_CMP0_REG1, cycle_time);

	icss_iep_set_counter(iep, 0);
	icss_iep_enable(iep);
}

static void icss_iep_set_default_inc(struct icss_iep *iep, u8 def_inc)
{
	regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_CFG_REG,
			   IEP_GLOBAL_CFG_DEFAULT_INC_MASK,
			   def_inc << IEP_GLOBAL_CFG_DEFAULT_INC_SHIFT);
}

static void icss_iep_set_compensation_inc(struct icss_iep *iep, u16 compen_inc)
{
	struct device *dev = regmap_get_device(iep->map);

	if (compen_inc > IEP_MAX_COMPEN_INC) {
		dev_err(dev, "%s: too high compensation inc %d\n",
			__func__, compen_inc);
		compen_inc = IEP_MAX_COMPEN_INC;
	}

	regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_CFG_REG,
			   IEP_GLOBAL_CFG_COMPEN_INC_MASK,
			   compen_inc << IEP_GLOBAL_CFG_COMPEN_INC_SHIFT);
}

static void icss_iep_set_compensation_count(struct icss_iep *iep,
					    u32 compen_count)
{
	struct device *dev = regmap_get_device(iep->map);

	if (compen_count > IEP_MAX_COMPEN_COUNT) {
		dev_err(dev, "%s: too high compensation count %d\n",
			__func__, compen_count);
		compen_count = IEP_MAX_COMPEN_COUNT;
	}

	regmap_write(iep->map, ICSS_IEP_COMPEN_REG, compen_count);
}

static void icss_iep_set_slow_compensation_count(struct icss_iep *iep,
						 u32 compen_count)
{
	regmap_write(iep->map, ICSS_IEP_SLOW_COMPEN_REG, compen_count);
}

/* PTP PHC operations */
static int icss_iep_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
{
	struct icss_iep *iep = container_of(ptp, struct icss_iep, ptp_info);
	s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
	u32 cyc_count;
	u16 cmp_inc;

	mutex_lock(&iep->ptp_clk_mutex);

	/* ppb is amount of frequency we want to adjust in 1GHz (billion)
	 * e.g. 100ppb means we need to speed up clock by 100Hz
	 * i.e. at end of 1 second (1 billion ns) clock time, we should be
	 * counting 100 more ns.
	 * We use IEP slow compensation to achieve continuous freq. adjustment.
	 * There are 2 parts. Cycle time and adjustment per cycle.
	 * Simplest case would be 1 sec Cycle time. Then adjustment
	 * pre cycle would be (def_inc + ppb) value.
	 * Cycle time will have to be chosen based on how worse the ppb is.
	 * e.g. smaller the ppb, cycle time has to be large.
	 * The minimum adjustment we can do is +-1ns per cycle so let's
	 * reduce the cycle time to get 1ns per cycle adjustment.
	 *	1ppb = 1sec cycle time & 1ns adjust
	 *	1000ppb = 1/1000 cycle time & 1ns adjust per cycle
	 */

	if (iep->cycle_time_ns)
		iep->slow_cmp_inc = iep->clk_tick_time;	/* 4ns adj per cycle */
	else
		iep->slow_cmp_inc = 1;	/* 1ns adjust per cycle */

	if (ppb < 0) {
		iep->slow_cmp_inc = -iep->slow_cmp_inc;
		ppb = -ppb;
	}

	cyc_count = NSEC_PER_SEC;		/* 1s cycle time @1GHz */
	cyc_count /= ppb;		/* cycle time per ppb */

	/* slow_cmp_count is decremented every clock cycle, e.g. @250MHz */
	if (!iep->cycle_time_ns)
		cyc_count /= iep->clk_tick_time;
	iep->slow_cmp_count = cyc_count;

	/* iep->clk_tick_time is def_inc */
	cmp_inc = iep->clk_tick_time + iep->slow_cmp_inc;
	icss_iep_set_compensation_inc(iep, cmp_inc);
	icss_iep_set_slow_compensation_count(iep, iep->slow_cmp_count);

	mutex_unlock(&iep->ptp_clk_mutex);

	return 0;
}

static int icss_iep_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
	struct icss_iep *iep = container_of(ptp, struct icss_iep, ptp_info);
	s64 ns;

	mutex_lock(&iep->ptp_clk_mutex);
	if (iep->ops && iep->ops->adjtime) {
		iep->ops->adjtime(iep->clockops_data, delta);
	} else {
		ns = icss_iep_gettime(iep, NULL);
		ns += delta;
		icss_iep_settime(iep, ns);
	}
	mutex_unlock(&iep->ptp_clk_mutex);

	return 0;
}

static int icss_iep_ptp_gettimeex(struct ptp_clock_info *ptp,
				  struct timespec64 *ts,
				  struct ptp_system_timestamp *sts)
{
	struct icss_iep *iep = container_of(ptp, struct icss_iep, ptp_info);
	u64 ns;

	mutex_lock(&iep->ptp_clk_mutex);
	ns = icss_iep_gettime(iep, sts);
	*ts = ns_to_timespec64(ns);
	mutex_unlock(&iep->ptp_clk_mutex);

	return 0;
}

static int icss_iep_ptp_settime(struct ptp_clock_info *ptp,
				const struct timespec64 *ts)
{
	struct icss_iep *iep = container_of(ptp, struct icss_iep, ptp_info);
	u64 ns;

	mutex_lock(&iep->ptp_clk_mutex);
	ns = timespec64_to_ns(ts);
	icss_iep_settime(iep, ns);
	mutex_unlock(&iep->ptp_clk_mutex);

	return 0;
}

static void icss_iep_update_to_next_boundary(struct icss_iep *iep, u64 start_ns)
{
	u64 ns, p_ns;
	u32 offset;

	ns = icss_iep_gettime(iep, NULL);
	if (start_ns < ns)
		start_ns = ns;
	p_ns = iep->period;
	/* Round up to next period boundary */
	start_ns += p_ns - 1;
	offset = do_div(start_ns, p_ns);
	start_ns = start_ns * p_ns;
	/* If it is too close to update, shift to next boundary */
	if (p_ns - offset < 10)
		start_ns += p_ns;

	regmap_write(iep->map, ICSS_IEP_CMP1_REG0, lower_32_bits(start_ns));
	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
		regmap_write(iep->map, ICSS_IEP_CMP1_REG1, upper_32_bits(start_ns));
}

static int icss_iep_perout_enable_hw(struct icss_iep *iep,
				     struct ptp_perout_request *req, int on)
{
	struct timespec64 ts;
	u64 ns_start;
	u64 ns_width;
	int ret;
	u64 cmp;

	if (!on) {
		/* Disable CMP 1 */
		regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
				   IEP_CMP_CFG_CMP_EN(1), 0);

		/* clear CMP regs */
		regmap_write(iep->map, ICSS_IEP_CMP1_REG0, 0);
		if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
			regmap_write(iep->map, ICSS_IEP_CMP1_REG1, 0);

		/* Disable sync */
		regmap_write(iep->map, ICSS_IEP_SYNC_CTRL_REG, 0);

		return 0;
	}

	/* Calculate width of the signal for PPS/PEROUT handling */
	ts.tv_sec = req->on.sec;
	ts.tv_nsec = req->on.nsec;
	ns_width = timespec64_to_ns(&ts);

	if (req->flags & PTP_PEROUT_PHASE) {
		ts.tv_sec = req->phase.sec;
		ts.tv_nsec = req->phase.nsec;
		ns_start = timespec64_to_ns(&ts);
	} else {
		ns_start = 0;
	}

	if (iep->ops && iep->ops->perout_enable) {
		ret = iep->ops->perout_enable(iep->clockops_data, req, on, &cmp);
		if (ret)
			return ret;

		/* Configure CMP */
		regmap_write(iep->map, ICSS_IEP_CMP1_REG0, lower_32_bits(cmp));
		if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
			regmap_write(iep->map, ICSS_IEP_CMP1_REG1, upper_32_bits(cmp));
		/* Configure SYNC, based on req on width */
		regmap_write(iep->map, ICSS_IEP_SYNC_PWIDTH_REG,
			     div_u64(ns_width, iep->def_inc));
		regmap_write(iep->map, ICSS_IEP_SYNC0_PERIOD_REG, 0);
		regmap_write(iep->map, ICSS_IEP_SYNC_START_REG,
			     div_u64(ns_start, iep->def_inc));
		regmap_write(iep->map, ICSS_IEP_SYNC_CTRL_REG, 0); /* one-shot mode */
		/* Enable CMP 1 */
		regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
				   IEP_CMP_CFG_CMP_EN(1), IEP_CMP_CFG_CMP_EN(1));
	} else {
		u64 start_ns;

		iep->period = ((u64)req->period.sec * NSEC_PER_SEC) +
				req->period.nsec;
		start_ns = ((u64)req->period.sec * NSEC_PER_SEC)
				+ req->period.nsec;
		icss_iep_update_to_next_boundary(iep, start_ns);

		regmap_write(iep->map, ICSS_IEP_SYNC_PWIDTH_REG,
			     div_u64(ns_width, iep->def_inc));
		regmap_write(iep->map, ICSS_IEP_SYNC_START_REG,
			     div_u64(ns_start, iep->def_inc));
		/* Enable Sync in single shot mode  */
		regmap_write(iep->map, ICSS_IEP_SYNC_CTRL_REG,
			     IEP_SYNC_CTRL_SYNC_N_EN(0) | IEP_SYNC_CTRL_SYNC_EN);
		/* Enable CMP 1 */
		regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
				   IEP_CMP_CFG_CMP_EN(1), IEP_CMP_CFG_CMP_EN(1));
	}

	return 0;
}

static int icss_iep_perout_enable(struct icss_iep *iep,
				  struct ptp_perout_request *req, int on)
{
	int ret = 0;

	if (!on)
		goto disable;

	/* Reject requests with unsupported flags */
	if (req->flags & ~(PTP_PEROUT_DUTY_CYCLE |
			  PTP_PEROUT_PHASE))
		return -EOPNOTSUPP;

	/* Set default "on" time (1ms) for the signal if not passed by the app */
	if (!(req->flags & PTP_PEROUT_DUTY_CYCLE)) {
		req->on.sec = 0;
		req->on.nsec = NSEC_PER_MSEC;
	}

disable:
	mutex_lock(&iep->ptp_clk_mutex);

	if (iep->pps_enabled) {
		ret = -EBUSY;
		goto exit;
	}

	if (iep->perout_enabled == !!on)
		goto exit;

	ret = icss_iep_perout_enable_hw(iep, req, on);
	if (!ret)
		iep->perout_enabled = !!on;

exit:
	mutex_unlock(&iep->ptp_clk_mutex);

	return ret;
}

static void icss_iep_cap_cmp_work(struct work_struct *work)
{
	struct icss_iep *iep = container_of(work, struct icss_iep, work);
	const u32 *reg_offs = iep->plat_data->reg_offs;
	struct ptp_clock_event pevent;
	unsigned int val;
	u64 ns, ns_next;

	mutex_lock(&iep->ptp_clk_mutex);

	ns = readl(iep->base + reg_offs[ICSS_IEP_CMP1_REG0]);
	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT) {
		val = readl(iep->base + reg_offs[ICSS_IEP_CMP1_REG1]);
		ns |= (u64)val << 32;
	}
	/* set next event */
	ns_next = ns + iep->period;
	writel(lower_32_bits(ns_next),
	       iep->base + reg_offs[ICSS_IEP_CMP1_REG0]);
	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
		writel(upper_32_bits(ns_next),
		       iep->base + reg_offs[ICSS_IEP_CMP1_REG1]);

	pevent.pps_times.ts_real = ns_to_timespec64(ns);
	pevent.type = PTP_CLOCK_PPSUSR;
	pevent.index = 0;
	ptp_clock_event(iep->ptp_clock, &pevent);
	dev_dbg(iep->dev, "IEP:pps ts: %llu next:%llu:\n", ns, ns_next);

	mutex_unlock(&iep->ptp_clk_mutex);
}

static irqreturn_t icss_iep_cap_cmp_irq(int irq, void *dev_id)
{
	struct icss_iep *iep = (struct icss_iep *)dev_id;
	const u32 *reg_offs = iep->plat_data->reg_offs;
	unsigned int val;

	val = readl(iep->base + reg_offs[ICSS_IEP_CMP_STAT_REG]);
	/* The driver only enables CMP1 */
	if (val & BIT(1)) {
		/* Clear the event */
		writel(BIT(1), iep->base + reg_offs[ICSS_IEP_CMP_STAT_REG]);
		if (iep->pps_enabled || iep->perout_enabled)
			schedule_work(&iep->work);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int icss_iep_pps_enable(struct icss_iep *iep, int on)
{
	struct ptp_clock_request rq;
	struct timespec64 ts;
	int ret = 0;
	u64 ns;

	mutex_lock(&iep->ptp_clk_mutex);

	if (iep->perout_enabled) {
		ret = -EBUSY;
		goto exit;
	}

	if (iep->pps_enabled == !!on)
		goto exit;

	rq.perout.index = 0;
	if (on) {
		ns = icss_iep_gettime(iep, NULL);
		ts = ns_to_timespec64(ns);
		rq.perout.flags = 0;
		rq.perout.period.sec = 1;
		rq.perout.period.nsec = 0;
		rq.perout.start.sec = ts.tv_sec + 2;
		rq.perout.start.nsec = 0;
		rq.perout.on.sec = 0;
		rq.perout.on.nsec = NSEC_PER_MSEC;
		ret = icss_iep_perout_enable_hw(iep, &rq.perout, on);
	} else {
		ret = icss_iep_perout_enable_hw(iep, &rq.perout, on);
		if (iep->cap_cmp_irq)
			cancel_work_sync(&iep->work);
	}

	if (!ret)
		iep->pps_enabled = !!on;

exit:
	mutex_unlock(&iep->ptp_clk_mutex);

	return ret;
}

static int icss_iep_extts_enable(struct icss_iep *iep, u32 index, int on)
{
	u32 val, cap;
	int ret = 0;

	mutex_lock(&iep->ptp_clk_mutex);

	if (iep->ops && iep->ops->extts_enable) {
		ret = iep->ops->extts_enable(iep->clockops_data, index, on);
		goto exit;
	}

	if (((iep->latch_enable & BIT(index)) >> index) == on)
		goto exit;

	regmap_read(iep->map, ICSS_IEP_CAPTURE_CFG_REG, &val);
	cap = IEP_CAP_CFG_CAP_ASYNC_EN(index) | IEP_CAP_CFG_CAPNR_1ST_EVENT_EN(index);
	if (on) {
		val |= cap;
		iep->latch_enable |= BIT(index);
	} else {
		val &= ~cap;
		iep->latch_enable &= ~BIT(index);
	}
	regmap_write(iep->map, ICSS_IEP_CAPTURE_CFG_REG, val);

exit:
	mutex_unlock(&iep->ptp_clk_mutex);

	return ret;
}

static int icss_iep_ptp_enable(struct ptp_clock_info *ptp,
			       struct ptp_clock_request *rq, int on)
{
	struct icss_iep *iep = container_of(ptp, struct icss_iep, ptp_info);

	switch (rq->type) {
	case PTP_CLK_REQ_PEROUT:
		return icss_iep_perout_enable(iep, &rq->perout, on);
	case PTP_CLK_REQ_PPS:
		return icss_iep_pps_enable(iep, on);
	case PTP_CLK_REQ_EXTTS:
		return icss_iep_extts_enable(iep, rq->extts.index, on);
	default:
		break;
	}

	return -EOPNOTSUPP;
}

static struct ptp_clock_info icss_iep_ptp_info = {
	.owner		= THIS_MODULE,
	.name		= "ICSS IEP timer",
	.max_adj	= 10000000,
	.adjfine	= icss_iep_ptp_adjfine,
	.adjtime	= icss_iep_ptp_adjtime,
	.gettimex64	= icss_iep_ptp_gettimeex,
	.settime64	= icss_iep_ptp_settime,
	.enable		= icss_iep_ptp_enable,
};

struct icss_iep *icss_iep_get_idx(struct device_node *np, int idx)
{
	struct platform_device *pdev;
	struct device_node *iep_np;
	struct icss_iep *iep;
	int ret;

	iep_np = of_parse_phandle(np, "ti,iep", idx);
	if (!iep_np)
		return ERR_PTR(-ENODEV);

	if (!of_device_is_available(iep_np)) {
		of_node_put(iep_np);
		return ERR_PTR(-ENODEV);
	}

	pdev = of_find_device_by_node(iep_np);
	of_node_put(iep_np);

	if (!pdev)
		/* probably IEP not yet probed */
		return ERR_PTR(-EPROBE_DEFER);

	iep = platform_get_drvdata(pdev);
	if (!iep) {
		ret = -EPROBE_DEFER;
		goto err_put_pdev;
	}

	device_lock(iep->dev);
	if (iep->client_np) {
		device_unlock(iep->dev);
		dev_err(iep->dev, "IEP is already acquired by %s",
			iep->client_np->name);
		ret = -EBUSY;
		goto err_put_pdev;
	}
	iep->client_np = np;
	device_unlock(iep->dev);

	return iep;

err_put_pdev:
	put_device(&pdev->dev);

	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(icss_iep_get_idx);

struct icss_iep *icss_iep_get(struct device_node *np)
{
	return icss_iep_get_idx(np, 0);
}
EXPORT_SYMBOL_GPL(icss_iep_get);

void icss_iep_put(struct icss_iep *iep)
{
	device_lock(iep->dev);
	iep->client_np = NULL;
	device_unlock(iep->dev);
	put_device(iep->dev);
}
EXPORT_SYMBOL_GPL(icss_iep_put);

void icss_iep_init_fw(struct icss_iep *iep)
{
	/* start IEP for FW use in raw 64bit mode, no PTP support */
	iep->clk_tick_time = iep->def_inc;
	iep->cycle_time_ns = 0;
	iep->ops = NULL;
	iep->clockops_data = NULL;
	icss_iep_set_default_inc(iep, iep->def_inc);
	icss_iep_set_compensation_inc(iep, iep->def_inc);
	icss_iep_set_compensation_count(iep, 0);
	regmap_write(iep->map, ICSS_IEP_SYNC_PWIDTH_REG, iep->refclk_freq / 10); /* 100 ms pulse */
	regmap_write(iep->map, ICSS_IEP_SYNC0_PERIOD_REG, 0);
	if (iep->plat_data->flags & ICSS_IEP_SLOW_COMPEN_REG_SUPPORT)
		icss_iep_set_slow_compensation_count(iep, 0);

	icss_iep_enable(iep);
	icss_iep_settime(iep, 0);
}
EXPORT_SYMBOL_GPL(icss_iep_init_fw);

void icss_iep_exit_fw(struct icss_iep *iep)
{
	icss_iep_disable(iep);
}
EXPORT_SYMBOL_GPL(icss_iep_exit_fw);

int icss_iep_init(struct icss_iep *iep, const struct icss_iep_clockops *clkops,
		  void *clockops_data, u32 cycle_time_ns)
{
	int ret = 0;

	iep->cycle_time_ns = cycle_time_ns;
	iep->clk_tick_time = iep->def_inc;
	iep->ops = clkops;
	iep->clockops_data = clockops_data;
	icss_iep_set_default_inc(iep, iep->def_inc);
	icss_iep_set_compensation_inc(iep, iep->def_inc);
	icss_iep_set_compensation_count(iep, 0);
	regmap_write(iep->map, ICSS_IEP_SYNC_PWIDTH_REG, iep->refclk_freq / 10); /* 100 ms pulse */
	regmap_write(iep->map, ICSS_IEP_SYNC0_PERIOD_REG, 0);
	if (iep->plat_data->flags & ICSS_IEP_SLOW_COMPEN_REG_SUPPORT)
		icss_iep_set_slow_compensation_count(iep, 0);

	if (!(iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT) ||
	    !(iep->plat_data->flags & ICSS_IEP_SLOW_COMPEN_REG_SUPPORT))
		goto skip_perout;

	if (iep->ops && iep->ops->perout_enable) {
		iep->ptp_info.n_per_out = 1;
		iep->ptp_info.pps = 1;
	} else if (iep->cap_cmp_irq) {
		iep->ptp_info.pps = 1;
	}

	if (iep->ops && iep->ops->extts_enable)
		iep->ptp_info.n_ext_ts = 2;

skip_perout:
	if (cycle_time_ns)
		icss_iep_enable_shadow_mode(iep);
	else
		icss_iep_enable(iep);
	icss_iep_settime(iep, ktime_get_real_ns());

	iep->ptp_clock = ptp_clock_register(&iep->ptp_info, iep->dev);
	if (IS_ERR(iep->ptp_clock)) {
		ret = PTR_ERR(iep->ptp_clock);
		iep->ptp_clock = NULL;
		dev_err(iep->dev, "Failed to register ptp clk %d\n", ret);
	}

	return ret;
}
EXPORT_SYMBOL_GPL(icss_iep_init);

int icss_iep_exit(struct icss_iep *iep)
{
	if (iep->ptp_clock) {
		ptp_clock_unregister(iep->ptp_clock);
		iep->ptp_clock = NULL;
	}
	icss_iep_disable(iep);

	if (iep->pps_enabled)
		icss_iep_pps_enable(iep, false);
	else if (iep->perout_enabled)
		icss_iep_perout_enable(iep, NULL, false);

	return 0;
}
EXPORT_SYMBOL_GPL(icss_iep_exit);

static int icss_iep_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct icss_iep *iep;
	struct clk *iep_clk;
	int ret, irq;

	iep = devm_kzalloc(dev, sizeof(*iep), GFP_KERNEL);
	if (!iep)
		return -ENOMEM;

	iep->dev = dev;
	iep->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(iep->base))
		return -ENODEV;

	irq = platform_get_irq_byname_optional(pdev, "iep_cap_cmp");
	if (irq == -EPROBE_DEFER)
		return irq;

	if (irq > 0) {
		ret = devm_request_irq(dev, irq, icss_iep_cap_cmp_irq,
				       IRQF_TRIGGER_HIGH, "iep_cap_cmp", iep);
		if (ret) {
			dev_info(iep->dev, "cap_cmp irq request failed: %x\n",
				 ret);
		} else {
			iep->cap_cmp_irq = irq;
			INIT_WORK(&iep->work, icss_iep_cap_cmp_work);
		}
	}

	iep_clk = devm_clk_get(dev, NULL);
	if (IS_ERR(iep_clk))
		return PTR_ERR(iep_clk);

	iep->refclk_freq = clk_get_rate(iep_clk);

	iep->def_inc = NSEC_PER_SEC / iep->refclk_freq;	/* ns per clock tick */
	if (iep->def_inc > IEP_MAX_DEF_INC) {
		dev_err(dev, "Failed to set def_inc %d.  IEP_clock is too slow to be supported\n",
			iep->def_inc);
		return -EINVAL;
	}

	iep->plat_data = device_get_match_data(dev);
	if (!iep->plat_data)
		return -EINVAL;

	iep->map = devm_regmap_init(dev, NULL, iep, iep->plat_data->config);
	if (IS_ERR(iep->map)) {
		dev_err(dev, "Failed to create regmap for IEP %ld\n",
			PTR_ERR(iep->map));
		return PTR_ERR(iep->map);
	}

	iep->ptp_info = icss_iep_ptp_info;
	mutex_init(&iep->ptp_clk_mutex);
	dev_set_drvdata(dev, iep);
	icss_iep_disable(iep);

	return 0;
}

static bool am654_icss_iep_valid_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case ICSS_IEP_GLOBAL_CFG_REG ... ICSS_IEP_SYNC_START_REG:
		return true;
	default:
		return false;
	}

	return false;
}

static int icss_iep_regmap_write(void *context, unsigned int reg,
				 unsigned int val)
{
	struct icss_iep *iep = context;

	writel(val, iep->base + iep->plat_data->reg_offs[reg]);

	return 0;
}

static int icss_iep_regmap_read(void *context, unsigned int reg,
				unsigned int *val)
{
	struct icss_iep *iep = context;

	*val = readl(iep->base + iep->plat_data->reg_offs[reg]);

	return 0;
}

static const struct regmap_config am654_icss_iep_regmap_config = {
	.name = "icss iep",
	.reg_stride = 1,
	.reg_write = icss_iep_regmap_write,
	.reg_read = icss_iep_regmap_read,
	.writeable_reg = am654_icss_iep_valid_reg,
	.readable_reg = am654_icss_iep_valid_reg,
	.fast_io = 1,
};

static const struct icss_iep_plat_data am654_icss_iep_plat_data = {
	.flags = ICSS_IEP_64BIT_COUNTER_SUPPORT |
		 ICSS_IEP_SLOW_COMPEN_REG_SUPPORT |
		 ICSS_IEP_SHADOW_MODE_SUPPORT,
	.reg_offs = {
		[ICSS_IEP_GLOBAL_CFG_REG] = 0x00,
		[ICSS_IEP_COMPEN_REG] = 0x08,
		[ICSS_IEP_SLOW_COMPEN_REG] = 0x0C,
		[ICSS_IEP_COUNT_REG0] = 0x10,
		[ICSS_IEP_COUNT_REG1] = 0x14,
		[ICSS_IEP_CAPTURE_CFG_REG] = 0x18,
		[ICSS_IEP_CAPTURE_STAT_REG] = 0x1c,

		[ICSS_IEP_CAP6_RISE_REG0] = 0x50,
		[ICSS_IEP_CAP6_RISE_REG1] = 0x54,

		[ICSS_IEP_CAP7_RISE_REG0] = 0x60,
		[ICSS_IEP_CAP7_RISE_REG1] = 0x64,

		[ICSS_IEP_CMP_CFG_REG] = 0x70,
		[ICSS_IEP_CMP_STAT_REG] = 0x74,
		[ICSS_IEP_CMP0_REG0] = 0x78,
		[ICSS_IEP_CMP0_REG1] = 0x7c,
		[ICSS_IEP_CMP1_REG0] = 0x80,
		[ICSS_IEP_CMP1_REG1] = 0x84,

		[ICSS_IEP_CMP8_REG0] = 0xc0,
		[ICSS_IEP_CMP8_REG1] = 0xc4,
		[ICSS_IEP_SYNC_CTRL_REG] = 0x180,
		[ICSS_IEP_SYNC0_STAT_REG] = 0x188,
		[ICSS_IEP_SYNC1_STAT_REG] = 0x18c,
		[ICSS_IEP_SYNC_PWIDTH_REG] = 0x190,
		[ICSS_IEP_SYNC0_PERIOD_REG] = 0x194,
		[ICSS_IEP_SYNC1_DELAY_REG] = 0x198,
		[ICSS_IEP_SYNC_START_REG] = 0x19c,
	},
	.config = &am654_icss_iep_regmap_config,
};

static const struct icss_iep_plat_data am57xx_icss_iep_plat_data = {
	.flags = ICSS_IEP_64BIT_COUNTER_SUPPORT |
		 ICSS_IEP_SLOW_COMPEN_REG_SUPPORT,
	.reg_offs = {
		[ICSS_IEP_GLOBAL_CFG_REG] = 0x00,
		[ICSS_IEP_COMPEN_REG] = 0x08,
		[ICSS_IEP_SLOW_COMPEN_REG] = 0x0c,
		[ICSS_IEP_COUNT_REG0] = 0x10,
		[ICSS_IEP_COUNT_REG1] = 0x14,
		[ICSS_IEP_CAPTURE_CFG_REG] = 0x18,
		[ICSS_IEP_CAPTURE_STAT_REG] = 0x1c,

		[ICSS_IEP_CAP6_RISE_REG0] = 0x50,
		[ICSS_IEP_CAP6_RISE_REG1] = 0x54,

		[ICSS_IEP_CAP7_RISE_REG0] = 0x60,
		[ICSS_IEP_CAP7_RISE_REG1] = 0x64,

		[ICSS_IEP_CMP_CFG_REG] = 0x70,
		[ICSS_IEP_CMP_STAT_REG] = 0x74,
		[ICSS_IEP_CMP0_REG0] = 0x78,
		[ICSS_IEP_CMP0_REG1] = 0x7c,
		[ICSS_IEP_CMP1_REG0] = 0x80,
		[ICSS_IEP_CMP1_REG1] = 0x84,

		[ICSS_IEP_CMP8_REG0] = 0xc0,
		[ICSS_IEP_CMP8_REG1] = 0xc4,
		[ICSS_IEP_SYNC_CTRL_REG] = 0x180,
		[ICSS_IEP_SYNC0_STAT_REG] = 0x188,
		[ICSS_IEP_SYNC1_STAT_REG] = 0x18c,
		[ICSS_IEP_SYNC_PWIDTH_REG] = 0x190,
		[ICSS_IEP_SYNC0_PERIOD_REG] = 0x194,
		[ICSS_IEP_SYNC1_DELAY_REG] = 0x198,
		[ICSS_IEP_SYNC_START_REG] = 0x19c,
	},
	.config = &am654_icss_iep_regmap_config,
};

static bool am335x_icss_iep_valid_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case ICSS_IEP_GLOBAL_CFG_REG ... ICSS_IEP_CAPTURE_STAT_REG:
	case ICSS_IEP_CAP6_RISE_REG0:
	case ICSS_IEP_CMP_CFG_REG ... ICSS_IEP_CMP0_REG0:
	case ICSS_IEP_CMP8_REG0 ... ICSS_IEP_SYNC_START_REG:
		return true;
	default:
		return false;
	}
}

static const struct regmap_config am335x_icss_iep_regmap_config = {
	.name = "icss iep",
	.reg_stride = 1,
	.reg_write = icss_iep_regmap_write,
	.reg_read = icss_iep_regmap_read,
	.writeable_reg = am335x_icss_iep_valid_reg,
	.readable_reg = am335x_icss_iep_valid_reg,
};

static const struct icss_iep_plat_data am335x_icss_iep_plat_data = {
	.flags = 0,
	.reg_offs = {
		[ICSS_IEP_GLOBAL_CFG_REG] = 0x00,
		[ICSS_IEP_COMPEN_REG] = 0x08,
		[ICSS_IEP_COUNT_REG0] = 0x0c,
		[ICSS_IEP_CAPTURE_CFG_REG] = 0x10,
		[ICSS_IEP_CAPTURE_STAT_REG] = 0x14,

		[ICSS_IEP_CAP6_RISE_REG0] = 0x30,

		[ICSS_IEP_CAP7_RISE_REG0] = 0x38,

		[ICSS_IEP_CMP_CFG_REG] = 0x40,
		[ICSS_IEP_CMP_STAT_REG] = 0x44,
		[ICSS_IEP_CMP0_REG0] = 0x48,

		[ICSS_IEP_CMP8_REG0] = 0x88,
		[ICSS_IEP_SYNC_CTRL_REG] = 0x100,
		[ICSS_IEP_SYNC0_STAT_REG] = 0x108,
		[ICSS_IEP_SYNC1_STAT_REG] = 0x10c,
		[ICSS_IEP_SYNC_PWIDTH_REG] = 0x110,
		[ICSS_IEP_SYNC0_PERIOD_REG] = 0x114,
		[ICSS_IEP_SYNC1_DELAY_REG] = 0x118,
		[ICSS_IEP_SYNC_START_REG] = 0x11c,
	},
	.config = &am335x_icss_iep_regmap_config,
};

static const struct of_device_id icss_iep_of_match[] = {
	{
		.compatible = "ti,am654-icss-iep",
		.data = &am654_icss_iep_plat_data,
	},
	{
		.compatible = "ti,am5728-icss-iep",
		.data = &am57xx_icss_iep_plat_data,
	},
	{
		.compatible = "ti,am4376-icss-iep",
		.data = &am335x_icss_iep_plat_data,
	},
	{
		.compatible = "ti,am3356-icss-iep",
		.data = &am335x_icss_iep_plat_data,
	},
	{},
};
MODULE_DEVICE_TABLE(of, icss_iep_of_match);

static struct platform_driver icss_iep_driver = {
	.driver = {
		.name = "icss-iep",
		.of_match_table = icss_iep_of_match,
	},
	.probe = icss_iep_probe,
};
module_platform_driver(icss_iep_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("TI ICSS IEP driver");
MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
MODULE_AUTHOR("Md Danish Anwar <danishanwar@ti.com>");
