[PATCH v3 04/14] clk: clk-pic32: Add PIC32 clock driver

[Joshua Henderson]

From: Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>

This clock driver implements PIC32 specific clock-tree. clock-tree
entities can only be configured through device-tree file (OF).

Signed-off-by: Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
Signed-off-by: Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---
 drivers/clk/Kconfig     |    3 +
 drivers/clk/Makefile    |    1 +
 drivers/clk/clk-pic32.c | 1801 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1805 insertions(+)
 create mode 100644 drivers/clk/clk-pic32.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index c3e3a02..c05f44d 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -188,6 +188,9 @@ config COMMON_CLK_CDCE706
 	---help---
 	  This driver supports TI CDCE706 programmable 3-PLL clock synthesizer.
 
+config COMMON_CLK_PIC32
+	def_bool COMMON_CLK && MACH_PIC32
+
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
 source "drivers/clk/qcom/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 820714c..af737ab 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_ARCH_MOXART)		+= clk-moxart.o
 obj-$(CONFIG_ARCH_NOMADIK)		+= clk-nomadik.o
 obj-$(CONFIG_ARCH_NSPIRE)		+= clk-nspire.o
 obj-$(CONFIG_COMMON_CLK_PALMAS)		+= clk-palmas.o
+obj-$(CONFIG_COMMON_CLK_PIC32)		+= clk-pic32.o
 obj-$(CONFIG_CLK_QORIQ)			+= clk-qoriq.o
 obj-$(CONFIG_COMMON_CLK_RK808)		+= clk-rk808.o
 obj-$(CONFIG_COMMON_CLK_S2MPS11)	+= clk-s2mps11.o
diff --git a/drivers/clk/clk-pic32.c b/drivers/clk/clk-pic32.c
new file mode 100644
index 0000000..9dc5f78
--- /dev/null
+++ b/drivers/clk/clk-pic32.c
@@ -0,0 +1,1801 @@
+/*
+ * Purna Chandra Mandal,<purna.mandal@xxxxxxxxxxxxx>
+ * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/delay.h>
+#include <linux/debugfs.h>
+#include <asm/traps.h>
+#include <linux/slab.h>
+
+#include <asm/mach-pic32/pic32.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		0x01
+#define OSC_CLK_FAILED		0x04
+
+/* 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_ENABLED		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 /* Register offset w.r.t. REFO_CON_REG */
+#define REFO_TRIM_MASK		0x1ff
+#define REFO_TRIM_SHIFT		23
+#define REFO_TRIM_MAX		511
+
+/* FRC postscaler */
+#define OSC_FRCDIV_MASK		0x07
+#define OSC_FRCDIV_SHIFT	24
+
+/* FRC tuning */
+#define OSC_FRCTUN_MASK		0x3F
+#define OSC_FRCTUN_SHIFT	0
+
+/* SLEW Control Register fields */
+#define SLEW_BUSY		0x01
+#define SLEW_DOWNEN		0x02
+#define SLEW_UPEN		0x04
+#define SLEW_DIV		0x07
+#define SLEW_DIV_SHIFT		8
+#define SLEW_SYSDIV		0x0f
+#define SLEW_SYSDIV_SHIFT	20
+
+/* Common clock flags */
+#define CLK_ENABLED_ALWAYS	CLK_IGNORE_UNUSED
+#define CLK_DIV_FIXED		BIT(20)
+
+/* Sys Mux clock flags */
+#define SYS_MUX_POSTDIV		0x1
+#define SYS_MUX_SLEW		0x2
+
+#define LOCK_TIMEOUT_NS		(100 * NSEC_PER_MSEC)
+
+/* System PLL clk */
+struct pic32_spll {
+	struct clk_hw hw;
+	void __iomem *regs;
+	void __iomem *status_reg;
+	u32 pll_locked;
+	u8 idiv; /* pll-iclk divider, treating fixed */
+};
+
+/* System Clk */
+struct pic32_sclk {
+	struct clk_hw hw;
+	void __iomem *regs;
+	void __iomem *slwreg;
+	unsigned long flags;
+	u32 *parent_idx;
+	struct debugfs_regset32	regset;
+};
+
+/* Reference Oscillator */
+struct pic32_refosc {
+	struct clk_hw hw;
+	void __iomem *regs;
+	u32 *parent_idx;
+	struct debugfs_regset32	regset;
+};
+
+/* Peripheral Bus Clock */
+struct pic32_pbclk {
+	struct clk_hw hw;
+	void __iomem *regs;
+	u32 flags;
+	struct debugfs_regset32	regset;
+};
+
+/* External SOSC(fixed gated) clock  */
+struct pic32_sosc {
+	struct clk_hw hw;
+	void __iomem *regs;
+	void __iomem *status_reg;
+	unsigned long fixed_rate;
+	int bitmask;
+	int status_bitmask;
+};
+
+/* Soc specific clock reg-base */
+static void __iomem *pic32_clk_regbase;
+static struct clk *pic32_sys_clk;
+
+static DEFINE_SPINLOCK(lock);
+
+#define __clk_lock(flags)	spin_lock_irqsave(&lock, flags)
+#define __clk_unlock(flags)	spin_unlock_irqrestore(&lock, flags)
+
+/* execute unlock-sequence before writing to system registers */
+#define pic32_devcon_sysunlock()	pic32_syskey_unlock()
+#define pic32_devcon_syslock()
+
+/* 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)
+
+#define clkhw_to_spll(_hw)	container_of(_hw, struct pic32_spll, hw)
+#define clkhw_to_refosc(_hw)	container_of(_hw, struct pic32_refosc, hw)
+#define clkhw_to_pbclk(_hw)	container_of(_hw, struct pic32_pbclk, hw)
+#define clkhw_to_sys_clk(_hw)	container_of(_hw, struct pic32_sclk, hw)
+#define clkhw_to_sosc(_hw)	container_of(_hw, struct pic32_sosc, hw)
+
+/* pic32_of_clk_get_parent_indices - get parent clk hardware indices.
+ *
+ * This is useful specifically for mux clocks where some of possible parent-
+ * clocks logically been dropped thereby creating discontinuous linear
+ * sequence. This API refers OF property "microchip,clock-indices" of the
+ * device node to find h/w id(s) corresponding to each input clock source.
+ */
+int pic32_of_clk_get_parent_indices(struct device_node *np,
+				    u32 **table_p,
+				    int count)
+{
+	struct property *prop;
+	const __be32 *pv;
+	u32 i, *array, ret;
+
+	if ((!table_p) || (!count))
+		return -EINVAL;
+
+	prop = of_find_property(np, "microchip,clock-indices", NULL);
+	if (!prop) {
+		ret = 0;
+		goto out_err;
+	}
+
+	array = kzalloc((sizeof(u32) * count), GFP_KERNEL);
+	if (!array) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	for (i = 0, pv = NULL; i < count; i++) {
+		pv = of_prop_next_u32(prop, pv, &array[i]);
+		if (!pv) {
+			kfree(array);
+			ret = -EINVAL;
+			goto out_err;
+		}
+	}
+
+	*table_p = array;
+	return 0;
+out_err:
+	*table_p = NULL;
+	return ret;
+}
+EXPORT_SYMBOL(pic32_of_clk_get_parent_indices);
+
+static int pic32_of_clk_register_clkdev(struct device_node *np, struct clk *clk)
+{
+	int ret;
+
+	ret = clk_register_clkdev(clk, NULL, __clk_get_name(clk));
+	if (ret) {
+		pr_err("%s: clkdev register failed, ret %d\n",
+		       __clk_get_name(clk), ret);
+		goto out_err;
+	}
+
+	ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+
+out_err:
+	return ret;
+}
+
+static int pbclk_endisable(struct clk_hw *hw, int enable)
+{
+	struct pic32_pbclk *pb = clkhw_to_pbclk(hw);
+
+	if (enable)
+		clk_writel(PB_DIV_ENABLED, PIC32_SET(pb->regs));
+	else
+		clk_writel(PB_DIV_ENABLED, PIC32_CLR(pb->regs));
+	return 0;
+}
+
+static int pbclk_is_enabled(struct clk_hw *hw)
+{
+	u32 v;
+	struct pic32_pbclk *pb = clkhw_to_pbclk(hw);
+
+	v = clk_readl(pb->regs) & PB_DIV_ENABLED;
+	return !!v;
+}
+
+static int pbclk_enable(struct clk_hw *hw)
+{
+	return pbclk_endisable(hw, 1);
+}
+
+static void pbclk_disable(struct clk_hw *hw)
+{
+	struct pic32_pbclk *pb = clkhw_to_pbclk(hw);
+
+	if (pb->flags & CLK_ENABLED_ALWAYS)
+		return;
+
+	pbclk_endisable(hw, 0);
+	cpu_relax();
+}
+
+static unsigned long calc_best_divided_rate(unsigned long rate,
+					    unsigned long parent_rate,
+					    u32 divider_max,
+					    u32 divider_min)
+{
+	u32 divided_rate_up, divided_rate_down, best_rate;
+	u32 divider_down, divider_up;
+
+	/* eq. clk_rate = parent_rate / divider.
+	 *
+	 * Find best divider to produce closest of target divided rate.
+	 */
+
+	divider_down = parent_rate / rate;
+	divider_up = divider_down + 1;
+	if (divider_down >= divider_max) {
+		divider_down = divider_max;
+		divider_up = divider_down;
+	} else if (divider_down < divider_min) {
+		divider_down = divider_min;
+	}
+	divided_rate_up = parent_rate / divider_down;
+	divided_rate_down = parent_rate / divider_up;
+	if (abs(rate - divided_rate_down) < abs(rate - divided_rate_up))
+		best_rate = divided_rate_down;
+	else
+		best_rate = divided_rate_up;
+
+	return best_rate;
+}
+
+static inline u16 pbclk_read_pbdiv(struct pic32_pbclk *pb)
+{
+	u32 v = clk_readl(pb->regs);
+
+	return ((v >> PB_DIV_SHIFT) & PB_DIV_MASK) + 1;
+}
+
+static unsigned long pbclk_recalc_rate(struct clk_hw *hw,
+				       unsigned long parent_rate)
+{
+	struct pic32_pbclk *pb = clkhw_to_pbclk(hw);
+	unsigned long div, rate;
+
+	div = pbclk_read_pbdiv(pb);
+	rate = parent_rate / div;
+
+	return rate;
+}
+
+static long pbclk_round_rate(struct clk_hw *hw, unsigned long rate,
+			     unsigned long *parent_rate)
+{
+	long best_rate = calc_best_divided_rate(rate, *parent_rate,
+						PB_DIV_MAX, PB_DIV_MIN);
+	return best_rate;
+}
+
+static int pbclk_set_rate(struct clk_hw *hw, unsigned long rate,
+			  unsigned long parent_rate)
+{
+	struct pic32_pbclk *pb = clkhw_to_pbclk(hw);
+	u16 div, new_div;
+	unsigned long pbclk, flags, v;
+	ktime_t timeout;
+
+	/* fixed-div clk ? */
+	if (pb->flags & CLK_DIV_FIXED)
+		return -EINVAL;
+
+	/* calculate clkdiv and best rate */
+	new_div = parent_rate / rate;
+	pbclk = parent_rate / new_div;
+
+	/* check & wait for PBDIVRDY */
+	timeout = ktime_add_ns(ktime_get(), LOCK_TIMEOUT_NS);
+	for (;;) {
+		v = clk_readl(pb->regs);
+		if (v & PB_DIV_READY)
+			break;
+
+		if (ktime_after(ktime_get(), timeout)) {
+			pr_err("%s: pre_rate, busy while timeout\n",
+			       clk_hw_get_name(hw));
+			return -EPERM;
+		}
+		cpu_relax();
+	}
+
+	__clk_lock(flags);
+
+	/* apply new pbdiv */
+	v = clk_readl(pb->regs);
+	v &= ~PB_DIV_MASK;
+	v |= (new_div - 1);
+
+	/* sys unlock */
+	pic32_devcon_sysunlock();
+
+	clk_writel(v, pb->regs);
+
+	/* sys lock */
+	pic32_devcon_syslock();
+
+	__clk_unlock(flags);
+
+	/* wait again, for pbdivready */
+	timeout = ktime_add_ns(ktime_get(), LOCK_TIMEOUT_NS);
+	for (;;) {
+		v = clk_readl(pb->regs);
+		if (v & PB_DIV_READY)
+			break;
+
+		if (ktime_after(ktime_get(), timeout)) {
+			pr_err("%s: post_rate, busy while timeout\n",
+			       clk_hw_get_name(hw));
+			break;
+		}
+	}
+
+	/* confirm that new div is applied correctly */
+	div = pbclk_read_pbdiv(pb);
+	return (div == new_div) ? 0 : -EPERM;
+}
+
+static struct debugfs_reg32 pbclk_regs_debug[] = {
+	{ .name = "PBxDIV", .offset = 0,},
+};
+
+static int pbclk_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct pic32_pbclk *pb = clkhw_to_pbclk(hw);
+	struct dentry *file;
+
+	pb->regset.base = pb->regs;
+	pb->regset.regs = pbclk_regs_debug;
+	pb->regset.nregs = ARRAY_SIZE(pbclk_regs_debug);
+
+	file = debugfs_create_regset32("regdump", S_IRUGO, dentry, &pb->regset);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	return 0;
+}
+
+/* Reference Oscillator operations */
+static int roclk_endisable(struct clk_hw *hw, int enable)
+{
+	struct pic32_refosc *refo = clkhw_to_refosc(hw);
+
+	if (enable)
+		clk_writel(REFO_ON | REFO_OE, PIC32_SET(refo->regs));
+	else
+		clk_writel(REFO_ON | REFO_OE, PIC32_CLR(refo->regs));
+	return 0;
+}
+
+static int roclk_is_enabled(struct clk_hw *hw)
+{
+	struct pic32_refosc *refo = clkhw_to_refosc(hw);
+
+	return clk_readl(refo->regs) & REFO_ON;
+}
+
+static int roclk_enable(struct clk_hw *hw)
+{
+	return roclk_endisable(hw, 1);
+}
+
+static void roclk_disable(struct clk_hw *hw)
+{
+	roclk_endisable(hw, 0);
+	cpu_relax();
+}
+
+static void roclk_init(struct clk_hw *hw)
+{
+	roclk_disable(hw);
+}
+
+static u8 roclk_get_parent(struct clk_hw *hw)
+{
+	u8 i = 0;
+	struct pic32_refosc *refo = clkhw_to_refosc(hw);
+	unsigned long v;
+
+	v = clk_readl(refo->regs);
+	v = (v >> REFO_SEL_SHIFT) & REFO_SEL_MASK;
+
+	if (!refo->parent_idx)
+		goto done;
+
+	for (i = 0; i < clk_hw_get_num_parents(hw); i++)
+		if (refo->parent_idx[i] == v)
+			return (u8)i;
+done:
+	return (u8)v;
+}
+
+static int roclk_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct pic32_refosc *refo = clkhw_to_refosc(hw);
+	unsigned long v, flags;
+	u8 new_idx, cur_idx, was_disabled = 1;
+
+	new_idx = index;
+	if (refo->parent_idx && (index < clk_hw_get_num_parents(hw)))
+		new_idx = refo->parent_idx[index];
+
+	/* sanity */
+	v = clk_readl(refo->regs);
+	cur_idx = v & REFO_SEL_MASK;
+
+	if (unlikely(cur_idx == new_idx))
+		return 0;
+
+	/*
+	 * Note: clk-src switching is allowed only when module is not ACTIVE.
+	 * Module gets ACTIVE when enabled. So it meant set_parent() needs
+	 * clk-gating across the call.
+	 */
+	if (roclk_is_enabled(hw)) {
+		pr_warn("%s needs gated clock. Forcing.\n", __func__);
+		roclk_disable(hw);
+		was_disabled = 0;
+	}
+
+	/* wait until ACTIVE bit is zero */
+	for (;;) {
+		v = clk_readl(refo->regs);
+		if ((v & REFO_ACTIVE) == 0)
+			break;
+	}
+
+	__clk_lock(flags);
+
+	/* sysunlock */
+	pic32_devcon_sysunlock();
+
+	/* Calculate REFOCON register value */
+	v = clk_readl(refo->regs);
+	v &= ~(REFO_SEL_MASK << REFO_SEL_SHIFT);
+	v |= (new_idx << REFO_SEL_SHIFT);
+
+	/* Apply */
+	clk_writel(v, refo->regs);
+
+	/* syslock */
+	pic32_devcon_syslock();
+
+	/* enable module */
+	clk_writel(REFO_ON | REFO_OE, PIC32_SET(refo->regs));
+
+	__clk_unlock(flags);
+
+	/* keep it disabled, if it was */
+	if (was_disabled)
+		clk_writel(REFO_ON, PIC32_CLR(refo->regs));
+
+	return 0;
+}
+
+static unsigned long roclk_calc_rate(unsigned long parent_rate,
+				     u16 rodiv, u16 rotrim)
+{
+	u64 rate64;
+	u32 N;
+
+	N = rodiv;
+	/* fout = fin / [2 * {N + (M / 512)}]
+	 *	= fin * 512 / [1024 * N + 2 * M]
+	 *	= fin * 256 / (512 * N + M)
+	 *	= (fin << 8) / ((N << 9) + M)
+	 */
+	if (rotrim) {
+		N = (N << 9) + rotrim;
+		rate64 = parent_rate;
+		rate64 <<= 8;
+		do_div(rate64, N);
+	} else {
+		rate64 = parent_rate / (N << 1);
+	}
+	return (unsigned long)rate64;
+}
+
+static void roclk_calc_div_trim(unsigned long rate,
+				unsigned long parent_rate,
+				u16 *rodiv_p, u16 *rotrim_p)
+{
+	u16 div, rotrim, rodiv;
+	u64 frac;
+
+	/* Find integer approximation of floating-point arithmatic.
+	 *      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 : (u16)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_refosc *refo = clkhw_to_refosc(hw);
+	unsigned long v;
+	u16 rodiv, rotrim;
+
+	/* get rodiv */
+	v = clk_readl(refo->regs);
+	rodiv = (v >> REFO_DIV_SHIFT) & REFO_DIV_MASK;
+
+	/* get trim */
+	v = clk_readl(refo->regs + REFO_TRIM_REG);
+	rotrim = (v >> REFO_TRIM_SHIFT) & REFO_TRIM_MASK;
+
+	v = roclk_calc_rate(parent_rate, rodiv, rotrim);
+	return v;
+}
+
+static long roclk_round_rate(struct clk_hw *hw, unsigned long rate,
+			     unsigned long *parent_rate)
+{
+	u16 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);
+		best_parent_clk = clk_hw_get_parent(hw);
+		best_parent_rate = clk_hw_get_rate(best_parent_clk);
+		best = 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_rate_and_parent(struct clk_hw *hw,
+				     unsigned long rate,
+				     unsigned long parent_rate,
+				     u8 index)
+{
+	struct pic32_refosc *refo = clkhw_to_refosc(hw);
+	u16 trim, rodiv, parent_id, was_disabled = 1;
+	unsigned long flags, v;
+
+	if (unlikely(clk_hw_get_rate(hw) == rate))
+		return 0;
+
+	/* 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);
+
+	/* Note: rosel can only be programmed when module is INACTIVE.
+	 * i.e gating is required across set_parent.
+	 * So disable clk, if required.
+	 */
+	if (roclk_is_enabled(hw)) {
+		pr_err("%s: needs gating. Forcing.\n", __func__);
+		roclk_disable(hw);
+		was_disabled = 0;
+	}
+
+	/* check current source */
+	if (refo->parent_idx)
+		index = refo->parent_idx[index];
+
+	parent_id = roclk_get_parent(hw);
+	if (parent_id == index)
+		goto clk_rosel_ready;
+
+	/* wait till source change is active */
+	for (;;) {
+		v = clk_readl(refo->regs);
+		if ((v & (REFO_DIVSW_EN | REFO_ACTIVE)) == 0)
+			break;
+	}
+
+clk_rosel_ready:
+	/* spinlock */
+	__clk_lock(flags);
+	v = clk_readl(refo->regs);
+
+	/* sysunlock */
+	pic32_devcon_sysunlock();
+
+	/* apply parent, if required */
+	if (parent_id != 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);
+	clk_writel(v, refo->regs);
+
+	/* apply ROTRIM */
+	v = clk_readl(refo->regs + REFO_TRIM_REG);
+	v &= ~(REFO_TRIM_MASK << REFO_TRIM_SHIFT);
+	v |= (trim << REFO_TRIM_SHIFT);
+	clk_writel(v, refo->regs + REFO_TRIM_REG);
+
+	/* enable refo module */
+	clk_writel(REFO_ON | REFO_OE, PIC32_SET(refo->regs));
+
+	/* activate divider switching */
+	clk_writel(REFO_DIVSW_EN, PIC32_SET(refo->regs));
+
+	/* syslock */
+	pic32_devcon_syslock();
+
+	/* wait till divswen is in-progress */
+	for (;;) {
+		v = clk_readl(refo->regs);
+		if ((v & REFO_DIVSW_EN) == 0)
+			break;
+	}
+
+	__clk_unlock(flags);
+
+	/* keep it disabled if it was */
+	if (was_disabled)
+		clk_writel(REFO_ON, PIC32_CLR(refo->regs));
+
+	return 0;
+}
+
+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);
+}
+
+static struct debugfs_reg32 roclk_regs_debug[] = {
+	{ .name = "REFOxCON", .offset = 0,},
+	{ .name = "REFOxTRIM", .offset = REFO_TRIM_REG,},
+};
+
+static int roclk_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct pic32_refosc *ro = clkhw_to_refosc(hw);
+	struct dentry *file;
+
+	ro->regset.base = ro->regs;
+	ro->regset.regs = roclk_regs_debug;
+	ro->regset.nregs = ARRAY_SIZE(roclk_regs_debug);
+
+	file = debugfs_create_regset32("regdump", S_IRUGO, dentry, &ro->regset);
+
+	return IS_ERR(file) ? PTR_ERR(file) : 0;
+}
+
+static inline u8 spll_odiv_to_divider(u8 odiv)
+{
+	if (odiv <= PLL_ODIV_MIN)
+		odiv = PLL_ODIV_MIN;
+	else if (odiv >= PLL_ODIV_MAX)
+		odiv = PLL_ODIV_MAX;
+
+	return 1 << odiv;
+}
+
+static unsigned long spll_calc_mult_div(struct pic32_spll *pll,
+					unsigned long rate,
+					unsigned long parent_rate,
+					u8 *mult_p, u8 *odiv_p)
+{
+	u8 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 = (u32)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_spll *pll = clkhw_to_spll(hw);
+	unsigned long pll_in_rate, v;
+	u8 mult, odiv, div;
+	u64 rate64;
+
+	v = clk_readl(pll->regs);
+	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 = parent_rate / idiv
+	 * pll_out = pll_in * mult / div;
+	 */
+	pll_in_rate = parent_rate / pll->idiv;
+	rate64 = pll_in_rate;
+	rate64 *= mult;
+	do_div(rate64, div);
+
+	return (unsigned long)rate64;
+}
+
+static long spll_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *parent_rate)
+{
+	struct pic32_spll *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_spll *pll = clkhw_to_spll(hw);
+	u8 mult, odiv;
+	unsigned long ret, v, loop = 1000;
+	struct clk *sclk_parent;
+	unsigned long flags;
+
+	ret = spll_calc_mult_div(pll, rate, parent_rate, &mult, &odiv);
+	if (!ret || (ret == rate))
+		return 0;
+
+	/* To change frequency
+	 * - (a) check whether this clk is active parent of SYSCLK.
+	 * - (b) apply new mult & odiv.
+	 * - (c) switch back to PLL
+	 * - (d) wait until PLL settles down / locked.
+	 */
+
+	/* To check whether rate change is allowed we will have to ensure
+	 * spll_clk is not active parent of sys_clk.
+	 */
+	if (WARN_ON(IS_ERR_OR_NULL(pic32_sys_clk)))
+		return -EPERM;
+
+	/* get sysclk parent */
+	sclk_parent = clk_get_parent(pic32_sys_clk);
+
+	/* does sys_clk using spll_clk as parent ? */
+	if (unlikely(__clk_get_hw(sclk_parent) == hw)) {
+		pr_err("spll: set_rate() is not allowed when spll is parent of sys_clk.");
+		pr_err("First reparent sys_clk to frcdiv-clk and then try.\n");
+		return -EPERM;
+	}
+
+	/* lock */
+	__clk_lock(flags);
+
+	/* apply new multiplier & divisor (read-modify-write) */
+	v = clk_readl(pll->regs);
+	v &= ~(PLL_MULT_MASK << PLL_MULT_SHIFT);
+	v &= ~(PLL_ODIV_MASK << PLL_ODIV_SHIFT);
+	v |= (mult << PLL_MULT_SHIFT) | (odiv << PLL_ODIV_SHIFT);
+
+	/* sysunlock before writing to SPLLCON register */
+	pic32_devcon_sysunlock();
+
+	clk_writel(v, pll->regs);
+	cpu_relax();
+
+	/* insert few nops (5-stage) to ensure CPU does not hang */
+	cpu_nop5();
+	cpu_nop5();
+
+	/* syslock*/
+	pic32_devcon_syslock();
+
+	/* Wait until PLL is locked (maximum 100 usecs). */
+	for (;;) {
+		v = clk_readl(pll->status_reg);
+		if (v & pll->pll_locked)
+			break;
+
+		if (--loop == 0)
+			break;
+
+		ndelay(100);
+	}
+
+	/* lock */
+	__clk_unlock(flags);
+
+	return 0;
+}
+
+static struct debugfs_reg32 sclk_regs_debug[] = {
+	{ .name = "OSCCON", .offset = 0,},
+	{ .name = "OSCTUN", .offset = 0x10,},
+	{ .name = "SPLLCON", .offset = 0x20,},
+};
+
+static int sclk_debug_init(struct clk_hw *hw, struct dentry *dir)
+{
+	struct pic32_sclk *sclk = clkhw_to_sys_clk(hw);
+	struct dentry *file;
+
+	sclk->regset.base = sclk->regs;
+	sclk->regset.regs = sclk_regs_debug;
+	sclk->regset.nregs = ARRAY_SIZE(sclk_regs_debug);
+
+	file = debugfs_create_regset32("regdump", S_IRUGO, dir, &sclk->regset);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	return 0;
+}
+
+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 unsigned long sclk_get_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	u32 v, div;
+	struct pic32_sclk *sysclk = clkhw_to_sys_clk(hw);
+
+	v = clk_readl(sysclk->slwreg);
+	div = (v >> SLEW_SYSDIV_SHIFT) & SLEW_SYSDIV;
+	div += 1; /* sys-div to divider */
+
+	return parent_rate / div;
+}
+
+static int sclk_set_rate(struct clk_hw *hw,
+			 unsigned long rate, unsigned long parent_rate)
+{
+	u32 v, div;
+	unsigned long flags;
+	struct pic32_sclk *sysclk = clkhw_to_sys_clk(hw);
+	ktime_t timeout;
+
+	div = parent_rate / rate;
+
+	__clk_lock(flags);
+
+	/* sysunlock*/
+	pic32_devcon_sysunlock();
+
+	/* apply new div */
+	v = clk_readl(sysclk->slwreg);
+	v &= ~(SLEW_SYSDIV << SLEW_SYSDIV_SHIFT);
+	v |= ((div - 1) << SLEW_SYSDIV_SHIFT);
+	clk_writel(v, sysclk->slwreg);
+
+	/* syslock*/
+	pic32_devcon_syslock();
+
+	/* wait until BUSY is cleared */
+	timeout = ktime_add_ns(ktime_get(), LOCK_TIMEOUT_NS);
+	for (;;) {
+		v = clk_readl(sysclk->slwreg);
+		if (!(v & SLEW_BUSY))
+			break;
+
+		if (ktime_after(ktime_get(), timeout)) {
+			pr_err("%s: busy while timeout\n",
+			       clk_hw_get_name(hw));
+			break;
+		}
+	}
+	__clk_unlock(flags);
+
+	return 0;
+}
+
+static u8 sclk_get_parent(struct clk_hw *hw)
+{
+	u8 idx, i;
+	u32 v;
+	struct pic32_sclk *sysclk = clkhw_to_sys_clk(hw);
+
+	v = clk_readl(sysclk->regs);
+	idx = (v >> OSC_CUR_SHIFT) & OSC_CUR_MASK;
+
+	if (!sysclk->parent_idx)
+		goto done;
+
+	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
+		if (sysclk->parent_idx[i] == idx) {
+			idx = i;
+			break;
+		}
+	}
+
+done:
+	return idx;
+}
+
+static int sclk_set_parent(struct clk_hw *hw, u8 index)
+{
+	u32 v;
+	unsigned long flags, parent_rate;
+	u8 nosc, cosc;
+	struct pic32_sclk *sysclk = clkhw_to_sys_clk(hw);
+
+	/* find new_osc */
+	nosc = sysclk->parent_idx ? sysclk->parent_idx[index] : index;
+
+	/* check cur_osc is not same as new_osc */
+	v = clk_readl(sysclk->regs);
+	cosc = (v >> OSC_CUR_SHIFT) & OSC_CUR_MASK;
+	if (unlikely(cosc == nosc))
+		return 0;
+
+	parent_rate = clk_hw_get_rate(clk_hw_get_parent_by_index(hw, index));
+
+	/* spin lock */
+	__clk_lock(flags);
+
+	/* sysunlock*/
+	pic32_devcon_sysunlock();
+
+	/* set new parent */
+	v = clk_readl(sysclk->regs);
+	v &= ~(OSC_NEW_MASK << OSC_NEW_SHIFT);
+	v |= (nosc << OSC_NEW_SHIFT);
+	clk_writel(v, sysclk->regs);
+
+	/* initate switch */
+	clk_writel(OSC_SWEN, PIC32_SET(sysclk->regs));
+	cpu_relax();
+
+	/* some nop to flush pipeline(cpu-clk is in-flux) */
+	cpu_nop5();
+
+	/* syslock */
+	pic32_devcon_syslock();
+
+	/* wait for SWEN bit to clear */
+	for (;;) {
+		v = clk_readl(sysclk->regs);
+		if (!(v & OSC_SWEN))
+			break;
+	}
+
+	/* spin unlock */
+	__clk_unlock(flags);
+
+	/* SYSCLK switch logic performs sanity and maintains state machine for
+	 * clock-switching. So h/w might reject clk-switch request if required
+	 * conditions (like clksrc not present or unstable) aren't met.
+	 * So confirm before claiming success.
+	 */
+	cosc = (v >> OSC_CUR_SHIFT) & OSC_CUR_MASK;
+	if (unlikely(cosc != nosc)) {
+		pr_err("%s: err COSC %d and NOSC %d\n",
+		       clk_hw_get_name(hw), cosc, nosc);
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int sosc_clk_enable(struct clk_hw *hw)
+{
+	int loop;
+	unsigned long flags;
+	struct pic32_sosc *sosc = clkhw_to_sosc(hw);
+
+	local_irq_save(flags);
+
+	/* enable SOSC */
+	pic32_devcon_sysunlock();
+	clk_writel(sosc->bitmask, PIC32_SET(sosc->regs));
+	pic32_devcon_syslock();
+
+	/* Wait till warm-up period expires and ready-status is updated */
+	for (loop = 1024; loop; --loop) {
+		cpu_relax();
+		if (clk_readl(sosc->status_reg) & sosc->status_bitmask)
+			break;
+	}
+
+	local_irq_restore(flags);
+
+	if (!loop) {
+		pr_err("%s: possibly clk is not present or ready for ops\n",
+		       clk_hw_get_name(hw));
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static void sosc_clk_disable(struct clk_hw *hw)
+{
+	struct pic32_sosc *sosc = clkhw_to_sosc(hw);
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	pic32_devcon_sysunlock();
+	clk_writel(sosc->bitmask, PIC32_CLR(sosc->regs));
+	pic32_devcon_syslock();
+
+	local_irq_restore(flags);
+}
+
+static int sosc_clk_is_enabled(struct clk_hw *hw)
+{
+	struct pic32_sosc *sosc = clkhw_to_sosc(hw);
+	u32 enable, status;
+
+	/* check enable & ready-status */
+	enable = clk_readl(sosc->regs) & sosc->bitmask;
+	status = clk_readl(sosc->status_reg) & sosc->status_bitmask;
+
+	return enable && status;
+}
+
+static unsigned long sosc_clk_calc_rate(struct clk_hw *hw,
+					unsigned long parent_rate)
+{
+	return clkhw_to_sosc(hw)->fixed_rate;
+}
+
+static struct clk_ops 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,
+	.debug_init	= pbclk_debug_init,
+};
+
+/* sysclk is a mux with post-divider.
+ * get/set_parent &  get/set_rate are required operation.
+ */
+static struct clk_ops sclk_postdiv_ops = {
+	.get_parent	= sclk_get_parent,
+	.set_parent	= sclk_set_parent,
+	.determine_rate = __clk_mux_determine_rate,
+	.round_rate	= sclk_round_rate,
+	.set_rate	= sclk_set_rate,
+	.recalc_rate	= sclk_get_rate,
+	.debug_init	= sclk_debug_init,
+};
+
+static struct clk_ops spll_clk_ops = {
+	.recalc_rate	= spll_clk_recalc_rate,
+	.round_rate	= spll_clk_round_rate,
+	.set_rate	= spll_clk_set_rate,
+};
+
+static struct clk_ops 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,
+	.round_rate		= roclk_round_rate,
+	.set_rate_and_parent	= roclk_set_rate_and_parent,
+	.set_rate		= roclk_set_rate,
+	.init			= roclk_init,
+	.debug_init		= roclk_debug_init,
+};
+
+static struct clk_ops sosc_ops = {
+	.enable = sosc_clk_enable,
+	.disable = sosc_clk_disable,
+	.is_enabled = sosc_clk_is_enabled,
+	.recalc_rate = sosc_clk_calc_rate,
+};
+
+#define init_clk_data(__initdata, __clk, __parents,	\
+	__nr_parents, __flags, __ops)			\
+	__initdata.name = (__clk);			\
+	__initdata.ops = (__ops);			\
+	__initdata.flags = (__flags);			\
+	__initdata.parent_names = (__parents);		\
+	__initdata.num_parents = (__nr_parents)
+
+static struct clk *periph_clk_register(const char *name,
+				       const char **parent_name,
+				       void __iomem *regs, u32 flags)
+{
+	struct clk *clk;
+	struct pic32_pbclk *pbclk;
+	struct clk_init_data init;
+
+	init_clk_data(init, name, parent_name, 1,
+		      flags | CLK_IS_BASIC, &pbclk_ops);
+
+	pbclk = kzalloc(sizeof(*pbclk), GFP_KERNEL);
+	if (!pbclk)
+		return ERR_PTR(-ENOMEM);
+
+	/* init */
+	pbclk->regs = regs;
+	pbclk->flags = flags;
+	pbclk->hw.init = &init;
+
+	clk = clk_register(NULL, &pbclk->hw);
+	if (IS_ERR(clk))
+		kfree(pbclk);
+
+	return clk;
+}
+
+static struct clk *sys_mux_clk_register(const char *name,
+					const char **parents,
+					const int num_parents,
+					void __iomem *regs,
+					void __iomem *slew_reg,
+					u32 *parent_idx,
+					const struct clk_ops *clkop)
+{
+	struct clk *clk;
+	struct pic32_sclk *sysclk;
+	struct clk_init_data init;
+
+	init_clk_data(init, name, parents, num_parents,
+		      CLK_IS_BASIC, clkop);
+
+	sysclk = kzalloc(sizeof(*sysclk), GFP_KERNEL);
+	if (!sysclk)
+		return ERR_PTR(-ENOMEM);
+
+	/* init sysclk data */
+	sysclk->hw.init = &init;
+	sysclk->regs = regs;
+	sysclk->slwreg = slew_reg;
+	sysclk->parent_idx = parent_idx;
+
+	clk = clk_register(NULL, &sysclk->hw);
+	if (IS_ERR(clk)) {
+		kfree(sysclk);
+		return clk;
+	}
+
+	/* Maintain reference to this clock;
+	 * This clock will be needed in spll-rate-change.
+	 */
+	pic32_sys_clk = clk;
+
+	return clk;
+}
+
+static struct clk *spll_clk_register(const char *name, const char *parents,
+				     void __iomem *regs,
+				     void __iomem *status_reg,
+				     u32 lock_bitmask)
+{
+	u32 v;
+	struct pic32_spll *pll;
+	struct clk_init_data init;
+	struct clk *clk;
+
+	init_clk_data(init, name, &parents, 1, CLK_IS_BASIC, &spll_clk_ops);
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	/* initialize configuration */
+	pll->regs = regs;
+	pll->status_reg = status_reg;
+	pll->pll_locked = lock_bitmask;
+	pll->hw.init = &init;
+
+	/* read and cache pll_idiv; we will use it as constant.*/
+	v = clk_readl(pll->regs);
+	pll->idiv = ((v >> PLL_IDIV_SHIFT) & PLL_IDIV_MASK) + 1;
+
+	clk = clk_register(NULL, &pll->hw);
+	if (IS_ERR(clk))
+		kfree(pll);
+
+	return clk;
+}
+
+static struct clk *refo_clk_register(const char *name,
+				     const char **parents,
+				     u32 nr_parents,
+				     void __iomem *regs,
+				     u32 *parent_idx)
+{
+	struct pic32_refosc *refo;
+	struct clk_init_data init;
+	struct clk *clk;
+	int clk_flags = CLK_IS_BASIC;
+
+	init_clk_data(init, name, parents, nr_parents, clk_flags, &roclk_ops);
+
+	refo = kmalloc(sizeof(*refo), GFP_KERNEL);
+	if (!refo)
+		return ERR_PTR(-ENOMEM);
+
+	/* initialize configuration */
+	refo->regs = regs;
+	refo->hw.init = &init;
+	refo->parent_idx = parent_idx;
+
+	clk = clk_register(NULL, &refo->hw);
+	if (IS_ERR(clk))
+		kfree(refo);
+
+	return clk;
+}
+
+static void __init of_sosc_clk_setup(struct device_node *np)
+{
+	u32 rate, stsmask, bitmask;
+	struct pic32_sosc *sosc;
+	struct clk *clk;
+	struct clk_init_data init;
+	void __iomem *regs, *status_reg;
+	const char *name = np->name;
+
+	if (of_property_read_u32(np, "clock-frequency", &rate))
+		return;
+
+	of_property_read_string(np, "clock-output-names", &name);
+
+	regs = of_iomap(np, 0);
+	if (!regs)
+		regs = pic32_clk_regbase;
+
+	status_reg = of_iomap(np, 1);
+	if (!status_reg)
+		status_reg = regs;
+
+	of_property_read_u32(np, "microchip,bit-mask", &bitmask);
+
+	of_property_read_u32(np, "microchip,status-bit-mask", &stsmask);
+
+	/* allocate fixed-rate clock */
+	sosc = kzalloc(sizeof(*sosc), GFP_KERNEL);
+	if (!sosc)
+		return;
+
+	init_clk_data(init, name, NULL, 0,
+		      CLK_IS_BASIC | CLK_IS_ROOT, &sosc_ops);
+
+	/* struct clk assignments */
+	sosc->fixed_rate = rate;
+	sosc->hw.init = &init;
+	sosc->regs = regs;
+	sosc->status_reg = status_reg;
+	sosc->bitmask = bitmask;
+	sosc->status_bitmask = stsmask;
+
+	/* register the clock */
+	clk = clk_register(NULL, &sosc->hw);
+	if (IS_ERR(clk))
+		kfree(sosc);
+	else
+		pic32_of_clk_register_clkdev(np, clk);
+}
+
+static void __init of_periph_clk_setup(struct device_node *np)
+{
+	const char *parent_name;
+	const char *name = np->name;
+	struct clk *clk;
+	u32 flags = 0;
+	void __iomem *regs;
+
+	regs = of_iomap(np, 0);
+	if (!regs) {
+		pr_err("%s: could not get reg property\n", name);
+		return;
+	}
+
+	parent_name = of_clk_get_parent_name(np, 0);
+	if (!parent_name) {
+		pr_err("pbclk: %s must have a parent\n", name);
+		goto err_map;
+	}
+
+	if (of_find_property(np, "microchip,ignore-unused", NULL)) {
+		flags |= CLK_IGNORE_UNUSED;
+		pr_info("%s: ignore gating even if unused\n", name);
+	}
+
+	of_property_read_string(np, "clock-output-names", &name);
+
+	/* register peripheral clock */
+	clk = periph_clk_register(name, &parent_name, regs, flags);
+	if (IS_ERR(clk)) {
+		pr_err("%s: could not register clock\n", name);
+		goto err_map;
+	}
+
+	pic32_of_clk_register_clkdev(np, clk);
+
+	return;
+
+err_map:
+	iounmap(regs);
+}
+
+static void __init of_refo_clk_setup(struct device_node *np)
+{
+	struct clk *clk;
+	int ret, count;
+	const char **parents;
+	const char *clk_name = np->name;
+	void __iomem *regs;
+	u32 *parent_idx;
+
+	/* get the input clock source count */
+	count = of_clk_get_parent_count(np);
+	if (count < 0) {
+		pr_err("%s: get clock count error\n", np->name);
+		return;
+	}
+
+	parents = kzalloc((sizeof(char *) * count), GFP_KERNEL);
+	if (!parents)
+		return;
+
+	ret = pic32_of_clk_get_parent_indices(np, &parent_idx, count);
+	if (ret)
+		goto err_parent;
+
+	of_clk_parent_fill(np, parents, count);
+
+	/* get iobase */
+	regs = of_iomap(np, 0);
+	if (!regs) {
+		pr_err("%s: could not get reg property\n", np->name);
+		goto err_parent_idx;
+	}
+
+	of_property_read_string(np, "clock-output-names", &clk_name);
+
+	clk = refo_clk_register(clk_name, parents, count, regs, parent_idx);
+	if (IS_ERR(clk)) {
+		pr_err("%s: could not register clock\n", clk_name);
+		goto err_map;
+	}
+
+	pic32_of_clk_register_clkdev(np, clk);
+
+	goto err_parent;
+
+err_map:
+	iounmap(regs);
+err_parent_idx:
+	kfree(parent_idx);
+err_parent:
+	kfree(parents);
+}
+
+static void __init of_sys_mux_slew_setup(struct device_node *np)
+{
+	struct clk *clk;
+	int ret, count;
+	const char *clk_name;
+	const char **parents;
+	u32 *parent_idx, slew, v;
+	unsigned long flags;
+	void __iomem *slew_reg;
+
+	/* get the input clock source count */
+	count = of_clk_get_parent_count(np);
+	if (count < 0) {
+		pr_err("%s: get clock count error\n", np->name);
+		return;
+	}
+
+	parents = kzalloc((sizeof(char *) * count), GFP_KERNEL);
+	if (!parents)
+		return;
+
+	ret = pic32_of_clk_get_parent_indices(np, &parent_idx, count);
+	if (ret)
+		goto err_name;
+
+	of_clk_parent_fill(np, parents, count);
+
+	ret = of_property_read_string_index(np, "clock-output-names",
+					    0, &clk_name);
+	if (ret)
+		clk_name = np->name;
+
+	/* get slew base */
+	slew_reg = of_iomap(np, 0);
+	if (!slew_reg) {
+		pr_warn("%s: no slew register ?\n", clk_name);
+		goto err_name;
+	}
+
+	/* register mux clk */
+	clk = sys_mux_clk_register(clk_name, parents, count, pic32_clk_regbase,
+				   slew_reg, parent_idx, &sclk_postdiv_ops);
+	if (IS_ERR(clk)) {
+		pr_err("%s: could not register clock\n", clk_name);
+		goto err_parent_idx;
+	}
+
+	/* enable slew, if asked */
+	if (!of_property_read_u32(np, "microchip,slew-step", &slew)) {
+		__clk_lock(flags);
+
+		v = clk_readl(slew_reg);
+		/* Apply new slew-div and enable up/down slewing */
+		v &= ~(SLEW_DIV << SLEW_DIV_SHIFT);
+		v |= (slew << SLEW_DIV_SHIFT);
+		v |= SLEW_DOWNEN | SLEW_UPEN;
+		clk_writel(v, slew_reg);
+
+		__clk_unlock(flags);
+	}
+
+	/* register clkdev */
+	pic32_of_clk_register_clkdev(np, clk);
+
+	goto err_name;
+
+err_parent_idx:
+	iounmap(slew_reg);
+	kfree(parent_idx);
+err_name:
+	kfree(parents);
+}
+
+static void __init of_sys_pll_setup(struct device_node *np)
+{
+	int count;
+	const char *clk_name = np->name;
+	const char **parent_names;
+	const char *plliclk_name = "spll_mux_clk";
+	void __iomem *regs, *stat_reg;
+	struct clk *clk, *mux_clk;
+	u32 bitmask;
+
+	/* get the input clock source count */
+	count = of_clk_get_parent_count(np);
+	if (count < 0) {
+		pr_err("%s: get clock count error, %d\n", np->name, count);
+		return;
+	}
+
+	parent_names = kzalloc((sizeof(char *) * count), GFP_KERNEL);
+	if (!parent_names)
+		return;
+
+	of_clk_parent_fill(np, parent_names, count);
+
+	/* get output name */
+	of_property_read_string(np, "clock-output-names", &clk_name);
+
+	/* get iobase */
+	regs = of_iomap(np, 0);
+	if (!regs) {
+		pr_err("%s: of_iomap failed\n", np->name);
+		goto err_name;
+	}
+
+	/* get status reg & status bitmask */
+	stat_reg = of_iomap(np, 1);
+
+	of_property_read_u32(np, "microchip,status-bit-mask", &bitmask);
+	if (!stat_reg || !bitmask)
+		pr_warn("%s: status_reg(or bit-mask) not found.\n", np->name);
+
+	/* register plliclk mux */
+	mux_clk = clk_register_mux(NULL, plliclk_name, parent_names,
+				   count, 0, regs,
+				   PLL_ICLK_SHIFT, 1, 0, &lock);
+	if (IS_ERR(mux_clk))  {
+		pr_err("splliclk_mux not registered\n");
+		goto err_unmap;
+	}
+
+	/* register sys-pll clock */
+	clk = spll_clk_register(clk_name, plliclk_name,
+				regs, stat_reg, bitmask);
+	if (IS_ERR(clk)) {
+		pr_err("spll_clk not registered\n");
+		goto err_mux;
+	}
+
+	pic32_of_clk_register_clkdev(np, clk);
+	goto err_name;
+
+err_mux:
+	clk_unregister(mux_clk);
+err_unmap:
+	iounmap(regs);
+err_name:
+	kfree(parent_names);
+}
+
+static void __init of_frcdiv_setup(struct device_node *np)
+{
+	struct clk *clk;
+	const char *clk_name = np->name;
+	const char *parent_name;
+
+	parent_name = of_clk_get_parent_name(np, 0);
+	if (!parent_name) {
+		pr_err("frcdiv: %s must have a parent\n", np->name);
+		return;
+	}
+
+	/* clk name */
+	of_property_read_string(np, "clock-output-names", &clk_name);
+
+	/* divider clock register */
+	clk = clk_register_divider(NULL, clk_name, parent_name,
+				   0, pic32_clk_regbase,
+				   OSC_FRCDIV_SHIFT, OSC_FRCDIV_MASK,
+				   CLK_DIVIDER_POWER_OF_TWO, &lock);
+
+	if (IS_ERR_OR_NULL(clk)) {
+		pr_err("frcdiv_clk not registered\n");
+		return;
+	}
+
+	pic32_of_clk_register_clkdev(np, clk);
+}
+
+static const struct of_device_id pic32_clk_match[] __initconst = {
+	{
+		.compatible = "microchip,pic32mzda-refoclk",
+		.data = of_refo_clk_setup,
+	},
+	{
+		.compatible = "microchip,pic32mzda-pbclk",
+		.data = of_periph_clk_setup,
+	},
+	{
+		.compatible = "microchip,pic32mzda-syspll",
+		.data = of_sys_pll_setup,
+	},
+	{
+		.compatible = "microchip,pic32mzda-sosc",
+		.data = of_sosc_clk_setup,
+	},
+	{
+		.compatible = "microchip,pic32mzda-frcdivclk",
+		.data = of_frcdiv_setup,
+	},
+	{
+		.compatible = "microchip,pic32mzda-sysclk-v2",
+		.data = of_sys_mux_slew_setup,
+	},
+	{}
+};
+
+static irqreturn_t pic32_fscm_isr_handler(int irq, void *data)
+{
+	u32 v = clk_readl(pic32_clk_regbase);
+
+	if (v & OSC_CLK_FAILED)
+		pr_info("pic32-clk: FSCM detected clk failure.\n");
+
+	return IRQ_HANDLED;
+}
+
+static int pic32_fscm_nmi(struct notifier_block *nb,
+			  unsigned long action, void *data)
+{
+	pic32_fscm_isr_handler(0, NULL);
+	return NOTIFY_OK;
+}
+
+static struct notifier_block failsafe_clk_notifier = {
+	.notifier_call = pic32_fscm_nmi,
+};
+
+static void __init of_pic32_soc_clock_init(struct device_node *np)
+{
+	int ret, nmi = 0, irq;
+	struct resource r;
+	struct device_node *childnp;
+	const struct of_device_id *clk_id;
+	void (*clk_setup)(struct device_node *);
+
+	if (of_address_to_resource(np, 0, &r))
+		panic("Failed to get clk-pll memory region\n");
+
+	if (!request_mem_region(r.start, resource_size(&r), r.name))
+		panic("%s: request_region failed\n", np->name);
+
+	pic32_clk_regbase = ioremap_nocache(r.start, resource_size(&r));
+	if (!pic32_clk_regbase)
+		panic("pic32-clk: failed to map registers\n");
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq) {
+		pr_warn("pic32-clk: irq not provided for FSCM; use nmi.\n");
+		nmi = 1;
+	}
+
+	for_each_child_of_node(np, childnp) {
+		clk_id = of_match_node(pic32_clk_match, childnp);
+		if (!clk_id)
+			continue;
+		clk_setup = clk_id->data;
+		clk_setup(childnp);
+	}
+
+	/* register irq/nmi */
+	if (nmi) {
+		register_nmi_notifier(&failsafe_clk_notifier);
+	} else {
+		ret = request_irq(irq, pic32_fscm_isr_handler, 0, "fscm", NULL);
+		if (ret)
+			pr_err("pic32-clk: fscm_irq request failed\n");
+	}
+}
+
+CLK_OF_DECLARE(pic32_soc_clk, "microchip,pic32mzda-clk",
+	       of_pic32_soc_clock_init);
-- 
1.7.9.5