// SPDX-License-Identifier: GPL-2.0-only
/*
 * Purna Chandra Mandal,<purna.mandal@microchip.com>
 * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
 */
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <asm/mach-pic32/pic32.h>
#include <asm/traps.h>

#include "clk-core.h"

/* OSCCON Reg fields */
#define OSC_CUR_MASK		0x07
#define OSC_CUR_SHIFT		12
#define OSC_NEW_MASK		0x07
#define OSC_NEW_SHIFT		8
#define OSC_SWEN		BIT(0)

/* SPLLCON Reg fields */
#define PLL_RANGE_MASK		0x07
#define PLL_RANGE_SHIFT		0
#define PLL_ICLK_MASK		0x01
#define PLL_ICLK_SHIFT		7
#define PLL_IDIV_MASK		0x07
#define PLL_IDIV_SHIFT		8
#define PLL_ODIV_MASK		0x07
#define PLL_ODIV_SHIFT		24
#define PLL_MULT_MASK		0x7F
#define PLL_MULT_SHIFT		16
#define PLL_MULT_MAX		128
#define PLL_ODIV_MIN		1
#define PLL_ODIV_MAX		5

/* Peripheral Bus Clock Reg Fields */
#define PB_DIV_MASK		0x7f
#define PB_DIV_SHIFT		0
#define PB_DIV_READY		BIT(11)
#define PB_DIV_ENABLE		BIT(15)
#define PB_DIV_MAX		128
#define PB_DIV_MIN		0

/* Reference Oscillator Control Reg fields */
#define REFO_SEL_MASK		0x0f
#define REFO_SEL_SHIFT		0
#define REFO_ACTIVE		BIT(8)
#define REFO_DIVSW_EN		BIT(9)
#define REFO_OE			BIT(12)
#define REFO_ON			BIT(15)
#define REFO_DIV_SHIFT		16
#define REFO_DIV_MASK		0x7fff

/* Reference Oscillator Trim Register Fields */
#define REFO_TRIM_REG		0x10
#define REFO_TRIM_MASK		0x1ff
#define REFO_TRIM_SHIFT		23
#define REFO_TRIM_MAX		511

/* Mux Slew Control Register fields */
#define SLEW_BUSY		BIT(0)
#define SLEW_DOWNEN		BIT(1)
#define SLEW_UPEN		BIT(2)
#define SLEW_DIV		0x07
#define SLEW_DIV_SHIFT		8
#define SLEW_SYSDIV		0x0f
#define SLEW_SYSDIV_SHIFT	20

/* Clock Poll Timeout */
#define LOCK_TIMEOUT_US         USEC_PER_MSEC

/* SoC specific clock needed during SPLL clock rate switch */
static struct clk_hw *pic32_sclk_hw;

/* add instruction pipeline delay while CPU clock is in-transition. */
#define cpu_nop5()			\
do {					\
	__asm__ __volatile__("nop");	\
	__asm__ __volatile__("nop");	\
	__asm__ __volatile__("nop");	\
	__asm__ __volatile__("nop");	\
	__asm__ __volatile__("nop");	\
} while (0)

/* Perpheral bus clocks */
struct pic32_periph_clk {
	struct clk_hw hw;
	void __iomem *ctrl_reg;
	struct pic32_clk_common *core;
};

#define clkhw_to_pbclk(_hw)	container_of(_hw, struct pic32_periph_clk, hw)

static int pbclk_is_enabled(struct clk_hw *hw)
{
	struct pic32_periph_clk *pb = clkhw_to_pbclk(hw);

	return readl(pb->ctrl_reg) & PB_DIV_ENABLE;
}

static int pbclk_enable(struct clk_hw *hw)
{
	struct pic32_periph_clk *pb = clkhw_to_pbclk(hw);

	writel(PB_DIV_ENABLE, PIC32_SET(pb->ctrl_reg));
	return 0;
}

static void pbclk_disable(struct clk_hw *hw)
{
	struct pic32_periph_clk *pb = clkhw_to_pbclk(hw);

	writel(PB_DIV_ENABLE, PIC32_CLR(pb->ctrl_reg));
}

static unsigned long calc_best_divided_rate(unsigned long rate,
					    unsigned long parent_rate,
					    u32 divider_max,
					    u32 divider_min)
{
	unsigned long divided_rate, divided_rate_down, best_rate;
	unsigned long div, div_up;

	/* eq. clk_rate = parent_rate / divider.
	 *
	 * Find best divider to produce closest of target divided rate.
	 */
	div = parent_rate / rate;
	div = clamp_val(div, divider_min, divider_max);
	div_up = clamp_val(div + 1, divider_min, divider_max);

	divided_rate = parent_rate / div;
	divided_rate_down = parent_rate / div_up;
	if (abs(rate - divided_rate_down) < abs(rate - divided_rate))
		best_rate = divided_rate_down;
	else
		best_rate = divided_rate;

	return best_rate;
}

static inline u32 pbclk_read_pbdiv(struct pic32_periph_clk *pb)
{
	return ((readl(pb->ctrl_reg) >> PB_DIV_SHIFT) & PB_DIV_MASK) + 1;
}

static unsigned long pbclk_recalc_rate(struct clk_hw *hw,
				       unsigned long parent_rate)
{
	struct pic32_periph_clk *pb = clkhw_to_pbclk(hw);

	return parent_rate / pbclk_read_pbdiv(pb);
}

static long pbclk_round_rate(struct clk_hw *hw, unsigned long rate,
			     unsigned long *parent_rate)
{
	return calc_best_divided_rate(rate, *parent_rate,
				      PB_DIV_MAX, PB_DIV_MIN);
}

static int pbclk_set_rate(struct clk_hw *hw, unsigned long rate,
			  unsigned long parent_rate)
{
	struct pic32_periph_clk *pb = clkhw_to_pbclk(hw);
	unsigned long flags;
	u32 v, div;
	int err;

	/* check & wait for DIV_READY */
	err = readl_poll_timeout(pb->ctrl_reg, v, v & PB_DIV_READY,
				 1, LOCK_TIMEOUT_US);
	if (err)
		return err;

	/* calculate clkdiv and best rate */
	div = DIV_ROUND_CLOSEST(parent_rate, rate);

	spin_lock_irqsave(&pb->core->reg_lock, flags);

	/* apply new div */
	v = readl(pb->ctrl_reg);
	v &= ~PB_DIV_MASK;
	v |= (div - 1);

	pic32_syskey_unlock();

	writel(v, pb->ctrl_reg);

	spin_unlock_irqrestore(&pb->core->reg_lock, flags);

	/* wait again for DIV_READY */
	err = readl_poll_timeout(pb->ctrl_reg, v, v & PB_DIV_READY,
				 1, LOCK_TIMEOUT_US);
	if (err)
		return err;

	/* confirm that new div is applied correctly */
	return (pbclk_read_pbdiv(pb) == div) ? 0 : -EBUSY;
}

const struct clk_ops pic32_pbclk_ops = {
	.enable		= pbclk_enable,
	.disable	= pbclk_disable,
	.is_enabled	= pbclk_is_enabled,
	.recalc_rate	= pbclk_recalc_rate,
	.round_rate	= pbclk_round_rate,
	.set_rate	= pbclk_set_rate,
};

struct clk *pic32_periph_clk_register(const struct pic32_periph_clk_data *desc,
				      struct pic32_clk_common *core)
{
	struct pic32_periph_clk *pbclk;
	struct clk *clk;

	pbclk = devm_kzalloc(core->dev, sizeof(*pbclk), GFP_KERNEL);
	if (!pbclk)
		return ERR_PTR(-ENOMEM);

	pbclk->hw.init = &desc->init_data;
	pbclk->core = core;
	pbclk->ctrl_reg = desc->ctrl_reg + core->iobase;

	clk = devm_clk_register(core->dev, &pbclk->hw);
	if (IS_ERR(clk)) {
		dev_err(core->dev, "%s: clk_register() failed\n", __func__);
		devm_kfree(core->dev, pbclk);
	}

	return clk;
}

/* Reference oscillator operations */
struct pic32_ref_osc {
	struct clk_hw hw;
	void __iomem *ctrl_reg;
	const u32 *parent_map;
	struct pic32_clk_common *core;
};

#define clkhw_to_refosc(_hw)	container_of(_hw, struct pic32_ref_osc, hw)

static int roclk_is_enabled(struct clk_hw *hw)
{
	struct pic32_ref_osc *refo = clkhw_to_refosc(hw);

	return readl(refo->ctrl_reg) & REFO_ON;
}

static int roclk_enable(struct clk_hw *hw)
{
	struct pic32_ref_osc *refo = clkhw_to_refosc(hw);

	writel(REFO_ON | REFO_OE, PIC32_SET(refo->ctrl_reg));
	return 0;
}

static void roclk_disable(struct clk_hw *hw)
{
	struct pic32_ref_osc *refo = clkhw_to_refosc(hw);

	writel(REFO_ON | REFO_OE, PIC32_CLR(refo->ctrl_reg));
}

static void roclk_init(struct clk_hw *hw)
{
	/* initialize clock in disabled state */
	roclk_disable(hw);
}

static u8 roclk_get_parent(struct clk_hw *hw)
{
	struct pic32_ref_osc *refo = clkhw_to_refosc(hw);
	u32 v, i;

	v = (readl(refo->ctrl_reg) >> REFO_SEL_SHIFT) & REFO_SEL_MASK;

	if (!refo->parent_map)
		return v;

	for (i = 0; i < clk_hw_get_num_parents(hw); i++)
		if (refo->parent_map[i] == v)
			return i;

	return -EINVAL;
}

static unsigned long roclk_calc_rate(unsigned long parent_rate,
				     u32 rodiv, u32 rotrim)
{
	u64 rate64;

	/* fout = fin / [2 * {div + (trim / 512)}]
	 *	= fin * 512 / [1024 * div + 2 * trim]
	 *	= fin * 256 / (512 * div + trim)
	 *	= (fin << 8) / ((div << 9) + trim)
	 */
	if (rotrim) {
		rodiv = (rodiv << 9) + rotrim;
		rate64 = parent_rate;
		rate64 <<= 8;
		do_div(rate64, rodiv);
	} else if (rodiv) {
		rate64 = parent_rate / (rodiv << 1);
	} else {
		rate64 = parent_rate;
	}
	return rate64;
}

static void roclk_calc_div_trim(unsigned long rate,
				unsigned long parent_rate,
				u32 *rodiv_p, u32 *rotrim_p)
{
	u32 div, rotrim, rodiv;
	u64 frac;

	/* Find integer approximation of floating-point arithmetic.
	 *      fout = fin / [2 * {rodiv + (rotrim / 512)}] ... (1)
	 * i.e. fout = fin / 2 * DIV
	 *      whereas DIV = rodiv + (rotrim / 512)
	 *
	 * Since kernel does not perform floating-point arithmatic so
	 * (rotrim/512) will be zero. And DIV & rodiv will result same.
	 *
	 * ie. fout = (fin * 256) / [(512 * rodiv) + rotrim]  ... from (1)
	 * ie. rotrim = ((fin * 256) / fout) - (512 * DIV)
	 */
	if (parent_rate <= rate) {
		div = 0;
		frac = 0;
		rodiv = 0;
		rotrim = 0;
	} else {
		div = parent_rate / (rate << 1);
		frac = parent_rate;
		frac <<= 8;
		do_div(frac, rate);
		frac -= (u64)(div << 9);

		rodiv = (div > REFO_DIV_MASK) ? REFO_DIV_MASK : div;
		rotrim = (frac >= REFO_TRIM_MAX) ? REFO_TRIM_MAX : frac;
	}

	if (rodiv_p)
		*rodiv_p = rodiv;

	if (rotrim_p)
		*rotrim_p = rotrim;
}

static unsigned long roclk_recalc_rate(struct clk_hw *hw,
				       unsigned long parent_rate)
{
	struct pic32_ref_osc *refo = clkhw_to_refosc(hw);
	u32 v, rodiv, rotrim;

	/* get rodiv */
	v = readl(refo->ctrl_reg);
	rodiv = (v >> REFO_DIV_SHIFT) & REFO_DIV_MASK;

	/* get trim */
	v = readl(refo->ctrl_reg + REFO_TRIM_REG);
	rotrim = (v >> REFO_TRIM_SHIFT) & REFO_TRIM_MASK;

	return roclk_calc_rate(parent_rate, rodiv, rotrim);
}

static long roclk_round_rate(struct clk_hw *hw, unsigned long rate,
			     unsigned long *parent_rate)
{
	u32 rotrim, rodiv;

	/* calculate dividers for new rate */
	roclk_calc_div_trim(rate, *parent_rate, &rodiv, &rotrim);

	/* caclulate new rate (rounding) based on new rodiv & rotrim */
	return roclk_calc_rate(*parent_rate, rodiv, rotrim);
}

static int roclk_determine_rate(struct clk_hw *hw,
				struct clk_rate_request *req)
{
	struct clk_hw *parent_clk, *best_parent_clk = NULL;
	unsigned int i, delta, best_delta = -1;
	unsigned long parent_rate, best_parent_rate = 0;
	unsigned long best = 0, nearest_rate;

	/* find a parent which can generate nearest clkrate >= rate */
	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
		/* get parent */
		parent_clk = clk_hw_get_parent_by_index(hw, i);
		if (!parent_clk)
			continue;

		/* skip if parent runs slower than target rate */
		parent_rate = clk_hw_get_rate(parent_clk);
		if (req->rate > parent_rate)
			continue;

		nearest_rate = roclk_round_rate(hw, req->rate, &parent_rate);
		delta = abs(nearest_rate - req->rate);
		if ((nearest_rate >= req->rate) && (delta < best_delta)) {
			best_parent_clk = parent_clk;
			best_parent_rate = parent_rate;
			best = nearest_rate;
			best_delta = delta;

			if (delta == 0)
				break;
		}
	}

	/* if no match found, retain old rate */
	if (!best_parent_clk) {
		pr_err("%s:%s, no parent found for rate %lu.\n",
		       __func__, clk_hw_get_name(hw), req->rate);
		return clk_hw_get_rate(hw);
	}

	pr_debug("%s,rate %lu, best_parent(%s, %lu), best %lu, delta %d\n",
		 clk_hw_get_name(hw), req->rate,
		 clk_hw_get_name(best_parent_clk), best_parent_rate,
		 best, best_delta);

	if (req->best_parent_rate)
		req->best_parent_rate = best_parent_rate;

	if (req->best_parent_hw)
		req->best_parent_hw = best_parent_clk;

	return best;
}

static int roclk_set_parent(struct clk_hw *hw, u8 index)
{
	struct pic32_ref_osc *refo = clkhw_to_refosc(hw);
	unsigned long flags;
	u32 v;
	int err;

	if (refo->parent_map)
		index = refo->parent_map[index];

	/* wait until ACTIVE bit is zero or timeout */
	err = readl_poll_timeout(refo->ctrl_reg, v, !(v & REFO_ACTIVE),
				 1, LOCK_TIMEOUT_US);
	if (err) {
		pr_err("%s: poll failed, clk active\n", clk_hw_get_name(hw));
		return err;
	}

	spin_lock_irqsave(&refo->core->reg_lock, flags);

	pic32_syskey_unlock();

	/* calculate & apply new */
	v = readl(refo->ctrl_reg);
	v &= ~(REFO_SEL_MASK << REFO_SEL_SHIFT);
	v |= index << REFO_SEL_SHIFT;

	writel(v, refo->ctrl_reg);

	spin_unlock_irqrestore(&refo->core->reg_lock, flags);

	return 0;
}

static int roclk_set_rate_and_parent(struct clk_hw *hw,
				     unsigned long rate,
				     unsigned long parent_rate,
				     u8 index)
{
	struct pic32_ref_osc *refo = clkhw_to_refosc(hw);
	unsigned long flags;
	u32 trim, rodiv, v;
	int err;

	/* calculate new rodiv & rotrim for new rate */
	roclk_calc_div_trim(rate, parent_rate, &rodiv, &trim);

	pr_debug("parent_rate = %lu, rate = %lu, div = %d, trim = %d\n",
		 parent_rate, rate, rodiv, trim);

	/* wait till source change is active */
	err = readl_poll_timeout(refo->ctrl_reg, v,
				 !(v & (REFO_ACTIVE | REFO_DIVSW_EN)),
				 1, LOCK_TIMEOUT_US);
	if (err) {
		pr_err("%s: poll timedout, clock is still active\n", __func__);
		return err;
	}

	spin_lock_irqsave(&refo->core->reg_lock, flags);
	v = readl(refo->ctrl_reg);

	pic32_syskey_unlock();

	/* apply parent, if required */
	if (refo->parent_map)
		index = refo->parent_map[index];

	v &= ~(REFO_SEL_MASK << REFO_SEL_SHIFT);
	v |= index << REFO_SEL_SHIFT;

	/* apply RODIV */
	v &= ~(REFO_DIV_MASK << REFO_DIV_SHIFT);
	v |= rodiv << REFO_DIV_SHIFT;
	writel(v, refo->ctrl_reg);

	/* apply ROTRIM */
	v = readl(refo->ctrl_reg + REFO_TRIM_REG);
	v &= ~(REFO_TRIM_MASK << REFO_TRIM_SHIFT);
	v |= trim << REFO_TRIM_SHIFT;
	writel(v, refo->ctrl_reg + REFO_TRIM_REG);

	/* enable & activate divider switching */
	writel(REFO_ON | REFO_DIVSW_EN, PIC32_SET(refo->ctrl_reg));

	/* wait till divswen is in-progress */
	err = readl_poll_timeout_atomic(refo->ctrl_reg, v, !(v & REFO_DIVSW_EN),
					1, LOCK_TIMEOUT_US);
	/* leave the clk gated as it was */
	writel(REFO_ON, PIC32_CLR(refo->ctrl_reg));

	spin_unlock_irqrestore(&refo->core->reg_lock, flags);

	return err;
}

static int roclk_set_rate(struct clk_hw *hw, unsigned long rate,
			  unsigned long parent_rate)
{
	u8 index = roclk_get_parent(hw);

	return roclk_set_rate_and_parent(hw, rate, parent_rate, index);
}

const struct clk_ops pic32_roclk_ops = {
	.enable			= roclk_enable,
	.disable		= roclk_disable,
	.is_enabled		= roclk_is_enabled,
	.get_parent		= roclk_get_parent,
	.set_parent		= roclk_set_parent,
	.determine_rate		= roclk_determine_rate,
	.recalc_rate		= roclk_recalc_rate,
	.set_rate_and_parent	= roclk_set_rate_and_parent,
	.set_rate		= roclk_set_rate,
	.init			= roclk_init,
};

struct clk *pic32_refo_clk_register(const struct pic32_ref_osc_data *data,
				    struct pic32_clk_common *core)
{
	struct pic32_ref_osc *refo;
	struct clk *clk;

	refo = devm_kzalloc(core->dev, sizeof(*refo), GFP_KERNEL);
	if (!refo)
		return ERR_PTR(-ENOMEM);

	refo->core = core;
	refo->hw.init = &data->init_data;
	refo->ctrl_reg = data->ctrl_reg + core->iobase;
	refo->parent_map = data->parent_map;

	clk = devm_clk_register(core->dev, &refo->hw);
	if (IS_ERR(clk))
		dev_err(core->dev, "%s: clk_register() failed\n", __func__);

	return clk;
}

struct pic32_sys_pll {
	struct clk_hw hw;
	void __iomem *ctrl_reg;
	void __iomem *status_reg;
	u32 lock_mask;
	u32 idiv; /* PLL iclk divider, treated fixed */
	struct pic32_clk_common *core;
};

#define clkhw_to_spll(_hw)	container_of(_hw, struct pic32_sys_pll, hw)

static inline u32 spll_odiv_to_divider(u32 odiv)
{
	odiv = clamp_val(odiv, PLL_ODIV_MIN, PLL_ODIV_MAX);

	return 1 << odiv;
}

static unsigned long spll_calc_mult_div(struct pic32_sys_pll *pll,
					unsigned long rate,
					unsigned long parent_rate,
					u32 *mult_p, u32 *odiv_p)
{
	u32 mul, div, best_mul = 1, best_div = 1;
	unsigned long new_rate, best_rate = rate;
	unsigned int best_delta = -1, delta, match_found = 0;
	u64 rate64;

	parent_rate /= pll->idiv;

	for (mul = 1; mul <= PLL_MULT_MAX; mul++) {
		for (div = PLL_ODIV_MIN; div <= PLL_ODIV_MAX; div++) {
			rate64 = parent_rate;
			rate64 *= mul;
			do_div(rate64, 1 << div);
			new_rate = rate64;
			delta = abs(rate - new_rate);
			if ((new_rate >= rate) && (delta < best_delta)) {
				best_delta = delta;
				best_rate = new_rate;
				best_mul = mul;
				best_div = div;
				match_found = 1;
			}
		}
	}

	if (!match_found) {
		pr_warn("spll: no match found\n");
		return 0;
	}

	pr_debug("rate %lu, par_rate %lu/mult %u, div %u, best_rate %lu\n",
		 rate, parent_rate, best_mul, best_div, best_rate);

	if (mult_p)
		*mult_p = best_mul - 1;

	if (odiv_p)
		*odiv_p = best_div;

	return best_rate;
}

static unsigned long spll_clk_recalc_rate(struct clk_hw *hw,
					  unsigned long parent_rate)
{
	struct pic32_sys_pll *pll = clkhw_to_spll(hw);
	unsigned long pll_in_rate;
	u32 mult, odiv, div, v;
	u64 rate64;

	v = readl(pll->ctrl_reg);
	odiv = ((v >> PLL_ODIV_SHIFT) & PLL_ODIV_MASK);
	mult = ((v >> PLL_MULT_SHIFT) & PLL_MULT_MASK) + 1;
	div = spll_odiv_to_divider(odiv);

	/* pll_in_rate = parent_rate / idiv
	 * pll_out_rate = pll_in_rate * mult / div;
	 */
	pll_in_rate = parent_rate / pll->idiv;
	rate64 = pll_in_rate;
	rate64 *= mult;
	do_div(rate64, div);

	return rate64;
}

static long spll_clk_round_rate(struct clk_hw *hw, unsigned long rate,
				unsigned long *parent_rate)
{
	struct pic32_sys_pll *pll = clkhw_to_spll(hw);

	return spll_calc_mult_div(pll, rate, *parent_rate, NULL, NULL);
}

static int spll_clk_set_rate(struct clk_hw *hw, unsigned long rate,
			     unsigned long parent_rate)
{
	struct pic32_sys_pll *pll = clkhw_to_spll(hw);
	unsigned long ret, flags;
	u32 mult, odiv, v;
	int err;

	ret = spll_calc_mult_div(pll, rate, parent_rate, &mult, &odiv);
	if (!ret)
		return -EINVAL;

	/*
	 * We can't change SPLL counters when it is in-active use
	 * by SYSCLK. So check before applying new counters/rate.
	 */

	/* Is spll_clk active parent of sys_clk ? */
	if (unlikely(clk_hw_get_parent(pic32_sclk_hw) == hw)) {
		pr_err("%s: failed, clk in-use\n", __func__);
		return -EBUSY;
	}

	spin_lock_irqsave(&pll->core->reg_lock, flags);

	/* apply new multiplier & divisor */
	v = readl(pll->ctrl_reg);
	v &= ~(PLL_MULT_MASK << PLL_MULT_SHIFT);
	v &= ~(PLL_ODIV_MASK << PLL_ODIV_SHIFT);
	v |= (mult << PLL_MULT_SHIFT) | (odiv << PLL_ODIV_SHIFT);

	/* sys unlock before write */
	pic32_syskey_unlock();

	writel(v, pll->ctrl_reg);
	cpu_relax();

	/* insert few nops (5-stage) to ensure CPU does not hang */
	cpu_nop5();
	cpu_nop5();

	/* Wait until PLL is locked (maximum 100 usecs). */
	err = readl_poll_timeout_atomic(pll->status_reg, v,
					v & pll->lock_mask, 1, 100);
	spin_unlock_irqrestore(&pll->core->reg_lock, flags);

	return err;
}

/* SPLL clock operation */
const struct clk_ops pic32_spll_ops = {
	.recalc_rate	= spll_clk_recalc_rate,
	.round_rate	= spll_clk_round_rate,
	.set_rate	= spll_clk_set_rate,
};

struct clk *pic32_spll_clk_register(const struct pic32_sys_pll_data *data,
				    struct pic32_clk_common *core)
{
	struct pic32_sys_pll *spll;
	struct clk *clk;

	spll = devm_kzalloc(core->dev, sizeof(*spll), GFP_KERNEL);
	if (!spll)
		return ERR_PTR(-ENOMEM);

	spll->core = core;
	spll->hw.init = &data->init_data;
	spll->ctrl_reg = data->ctrl_reg + core->iobase;
	spll->status_reg = data->status_reg + core->iobase;
	spll->lock_mask = data->lock_mask;

	/* cache PLL idiv; PLL driver uses it as constant.*/
	spll->idiv = (readl(spll->ctrl_reg) >> PLL_IDIV_SHIFT) & PLL_IDIV_MASK;
	spll->idiv += 1;

	clk = devm_clk_register(core->dev, &spll->hw);
	if (IS_ERR(clk))
		dev_err(core->dev, "sys_pll: clk_register() failed\n");

	return clk;
}

/* System mux clock(aka SCLK) */

struct pic32_sys_clk {
	struct clk_hw hw;
	void __iomem *mux_reg;
	void __iomem *slew_reg;
	u32 slew_div;
	const u32 *parent_map;
	struct pic32_clk_common *core;
};

#define clkhw_to_sys_clk(_hw)	container_of(_hw, struct pic32_sys_clk, hw)

static unsigned long sclk_get_rate(struct clk_hw *hw, unsigned long parent_rate)
{
	struct pic32_sys_clk *sclk = clkhw_to_sys_clk(hw);
	u32 div;

	div = (readl(sclk->slew_reg) >> SLEW_SYSDIV_SHIFT) & SLEW_SYSDIV;
	div += 1; /* sys-div to divider */

	return parent_rate / div;
}

static long sclk_round_rate(struct clk_hw *hw, unsigned long rate,
			    unsigned long *parent_rate)
{
	return calc_best_divided_rate(rate, *parent_rate, SLEW_SYSDIV, 1);
}

static int sclk_set_rate(struct clk_hw *hw,
			 unsigned long rate, unsigned long parent_rate)
{
	struct pic32_sys_clk *sclk = clkhw_to_sys_clk(hw);
	unsigned long flags;
	u32 v, div;
	int err;

	div = parent_rate / rate;

	spin_lock_irqsave(&sclk->core->reg_lock, flags);

	/* apply new div */
	v = readl(sclk->slew_reg);
	v &= ~(SLEW_SYSDIV << SLEW_SYSDIV_SHIFT);
	v |= (div - 1) << SLEW_SYSDIV_SHIFT;

	pic32_syskey_unlock();

	writel(v, sclk->slew_reg);

	/* wait until BUSY is cleared */
	err = readl_poll_timeout_atomic(sclk->slew_reg, v,
					!(v & SLEW_BUSY), 1, LOCK_TIMEOUT_US);

	spin_unlock_irqrestore(&sclk->core->reg_lock, flags);

	return err;
}

static u8 sclk_get_parent(struct clk_hw *hw)
{
	struct pic32_sys_clk *sclk = clkhw_to_sys_clk(hw);
	u32 i, v;

	v = (readl(sclk->mux_reg) >> OSC_CUR_SHIFT) & OSC_CUR_MASK;

	if (!sclk->parent_map)
		return v;

	for (i = 0; i < clk_hw_get_num_parents(hw); i++)
		if (sclk->parent_map[i] == v)
			return i;
	return -EINVAL;
}

static int sclk_set_parent(struct clk_hw *hw, u8 index)
{
	struct pic32_sys_clk *sclk = clkhw_to_sys_clk(hw);
	unsigned long flags;
	u32 nosc, cosc, v;
	int err;

	spin_lock_irqsave(&sclk->core->reg_lock, flags);

	/* find new_osc */
	nosc = sclk->parent_map ? sclk->parent_map[index] : index;

	/* set new parent */
	v = readl(sclk->mux_reg);
	v &= ~(OSC_NEW_MASK << OSC_NEW_SHIFT);
	v |= nosc << OSC_NEW_SHIFT;

	pic32_syskey_unlock();

	writel(v, sclk->mux_reg);

	/* initate switch */
	writel(OSC_SWEN, PIC32_SET(sclk->mux_reg));
	cpu_relax();

	/* add nop to flush pipeline (as cpu_clk is in-flux) */
	cpu_nop5();

	/* wait for SWEN bit to clear */
	err = readl_poll_timeout_atomic(sclk->slew_reg, v,
					!(v & OSC_SWEN), 1, LOCK_TIMEOUT_US);

	spin_unlock_irqrestore(&sclk->core->reg_lock, flags);

	/*
	 * SCLK clock-switching logic might reject a clock switching request
	 * if pre-requisites (like new clk_src not present or unstable) are
	 * not met.
	 * So confirm before claiming success.
	 */
	cosc = (readl(sclk->mux_reg) >> OSC_CUR_SHIFT) & OSC_CUR_MASK;
	if (cosc != nosc) {
		pr_err("%s: err, failed to set_parent() to %d, current %d\n",
		       clk_hw_get_name(hw), nosc, cosc);
		err = -EBUSY;
	}

	return err;
}

static void sclk_init(struct clk_hw *hw)
{
	struct pic32_sys_clk *sclk = clkhw_to_sys_clk(hw);
	unsigned long flags;
	u32 v;

	/* Maintain reference to this clk, required in spll_clk_set_rate() */
	pic32_sclk_hw = hw;

	/* apply slew divider on both up and down scaling */
	if (sclk->slew_div) {
		spin_lock_irqsave(&sclk->core->reg_lock, flags);
		v = readl(sclk->slew_reg);
		v &= ~(SLEW_DIV << SLEW_DIV_SHIFT);
		v |= sclk->slew_div << SLEW_DIV_SHIFT;
		v |= SLEW_DOWNEN | SLEW_UPEN;
		writel(v, sclk->slew_reg);
		spin_unlock_irqrestore(&sclk->core->reg_lock, flags);
	}
}

/* sclk with post-divider */
const struct clk_ops pic32_sclk_ops = {
	.get_parent	= sclk_get_parent,
	.set_parent	= sclk_set_parent,
	.round_rate	= sclk_round_rate,
	.set_rate	= sclk_set_rate,
	.recalc_rate	= sclk_get_rate,
	.init		= sclk_init,
	.determine_rate = __clk_mux_determine_rate,
};

/* sclk with no slew and no post-divider */
const struct clk_ops pic32_sclk_no_div_ops = {
	.get_parent	= sclk_get_parent,
	.set_parent	= sclk_set_parent,
	.init		= sclk_init,
	.determine_rate = __clk_mux_determine_rate,
};

struct clk *pic32_sys_clk_register(const struct pic32_sys_clk_data *data,
				   struct pic32_clk_common *core)
{
	struct pic32_sys_clk *sclk;
	struct clk *clk;

	sclk = devm_kzalloc(core->dev, sizeof(*sclk), GFP_KERNEL);
	if (!sclk)
		return ERR_PTR(-ENOMEM);

	sclk->core = core;
	sclk->hw.init = &data->init_data;
	sclk->mux_reg = data->mux_reg + core->iobase;
	sclk->slew_reg = data->slew_reg + core->iobase;
	sclk->slew_div = data->slew_div;
	sclk->parent_map = data->parent_map;

	clk = devm_clk_register(core->dev, &sclk->hw);
	if (IS_ERR(clk))
		dev_err(core->dev, "%s: clk register failed\n", __func__);

	return clk;
}

/* secondary oscillator */
struct pic32_sec_osc {
	struct clk_hw hw;
	void __iomem *enable_reg;
	void __iomem *status_reg;
	u32 enable_mask;
	u32 status_mask;
	unsigned long fixed_rate;
	struct pic32_clk_common *core;
};

#define clkhw_to_sosc(_hw)	container_of(_hw, struct pic32_sec_osc, hw)
static int sosc_clk_enable(struct clk_hw *hw)
{
	struct pic32_sec_osc *sosc = clkhw_to_sosc(hw);
	u32 v;

	/* enable SOSC */
	pic32_syskey_unlock();
	writel(sosc->enable_mask, PIC32_SET(sosc->enable_reg));

	/* wait till warm-up period expires or ready-status is updated */
	return readl_poll_timeout_atomic(sosc->status_reg, v,
					 v & sosc->status_mask, 1, 100);
}

static void sosc_clk_disable(struct clk_hw *hw)
{
	struct pic32_sec_osc *sosc = clkhw_to_sosc(hw);

	pic32_syskey_unlock();
	writel(sosc->enable_mask, PIC32_CLR(sosc->enable_reg));
}

static int sosc_clk_is_enabled(struct clk_hw *hw)
{
	struct pic32_sec_osc *sosc = clkhw_to_sosc(hw);
	u32 enabled, ready;

	/* check enabled and ready status */
	enabled = readl(sosc->enable_reg) & sosc->enable_mask;
	ready = readl(sosc->status_reg) & sosc->status_mask;

	return enabled && ready;
}

static unsigned long sosc_clk_calc_rate(struct clk_hw *hw,
					unsigned long parent_rate)
{
	return clkhw_to_sosc(hw)->fixed_rate;
}

const struct clk_ops pic32_sosc_ops = {
	.enable = sosc_clk_enable,
	.disable = sosc_clk_disable,
	.is_enabled = sosc_clk_is_enabled,
	.recalc_rate = sosc_clk_calc_rate,
};

struct clk *pic32_sosc_clk_register(const struct pic32_sec_osc_data *data,
				    struct pic32_clk_common *core)
{
	struct pic32_sec_osc *sosc;

	sosc = devm_kzalloc(core->dev, sizeof(*sosc), GFP_KERNEL);
	if (!sosc)
		return ERR_PTR(-ENOMEM);

	sosc->core = core;
	sosc->hw.init = &data->init_data;
	sosc->fixed_rate = data->fixed_rate;
	sosc->enable_mask = data->enable_mask;
	sosc->status_mask = data->status_mask;
	sosc->enable_reg = data->enable_reg + core->iobase;
	sosc->status_reg = data->status_reg + core->iobase;

	return devm_clk_register(core->dev, &sosc->hw);
}