clk: st: Support for QUADFS inside ClockGenB/C/D/E/F

The patch supports the 216/432/660 type Quad Frequency Synthesizers
used by ClockGenB/C/D/E/F

QUADFS clock : It includes support for all 216/432/660 type Quad
Frequency Synthesizers : implemented as Fixed Parent / Rate / Gate clock,
with clock rate calculated reading H/w settings done at BOOT.

QuadFS have 4 outputs : chan0 chan1 chan2 chan3

Signed-off-by: Pankaj Dev <pankaj.dev@st.com>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/st/Makefile

@@ -1 +1 @@
-obj-y += clkgen-mux.o clkgen-pll.o
+obj-y += clkgen-mux.o clkgen-pll.o clkgen-fsyn.o

drivers/clk/st/clkgen-fsyn.c

@@ -0,0 +1,1039 @@
+/*
+ * Copyright (C) 2014 STMicroelectronics R&D Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+/*
+ * Authors:
+ * Stephen Gallimore <stephen.gallimore@st.com>,
+ * Pankaj Dev <pankaj.dev@st.com>.
+ */
+
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/clk-provider.h>
+
+#include "clkgen.h"
+
+/*
+ * Maximum input clock to the PLL before we divide it down by 2
+ * although in reality in actual systems this has never been seen to
+ * be used.
+ */
+#define QUADFS_NDIV_THRESHOLD 30000000
+
+#define PLL_BW_GOODREF   (0L)
+#define PLL_BW_VBADREF   (1L)
+#define PLL_BW_BADREF    (2L)
+#define PLL_BW_VGOODREF  (3L)
+
+#define QUADFS_MAX_CHAN 4
+
+struct stm_fs {
+	unsigned long ndiv;
+	unsigned long mdiv;
+	unsigned long pe;
+	unsigned long sdiv;
+	unsigned long nsdiv;
+};
+
+static struct stm_fs fs216c65_rtbl[] = {
+	{ .mdiv = 0x1f, .pe = 0x0,	.sdiv = 0x7,	.nsdiv = 0 },	/* 312.5 Khz */
+	{ .mdiv = 0x17, .pe = 0x25ed,	.sdiv = 0x1,	.nsdiv = 0 },	/* 27    MHz */
+	{ .mdiv = 0x1a, .pe = 0x7b36,	.sdiv = 0x2,	.nsdiv = 1 },	/* 36.87 MHz */
+	{ .mdiv = 0x13, .pe = 0x0,	.sdiv = 0x2,	.nsdiv = 1 },	/* 48    MHz */
+	{ .mdiv = 0x11, .pe = 0x1c72,	.sdiv = 0x1,	.nsdiv = 1 },	/* 108   MHz */
+};
+
+static struct stm_fs fs432c65_rtbl[] = {
+	{ .mdiv = 0x1f, .pe = 0x0,	.sdiv = 0x7,	.nsdiv = 0 },	/* 625   Khz */
+	{ .mdiv = 0x11, .pe = 0x1c72,	.sdiv = 0x2,	.nsdiv = 1 },	/* 108   MHz */
+	{ .mdiv = 0x19, .pe = 0x121a,	.sdiv = 0x0,	.nsdiv = 1 },	/* 297   MHz */
+};
+
+static struct stm_fs fs660c32_rtbl[] = {
+	{ .mdiv = 0x01, .pe = 0x2aaa,	.sdiv = 0x8,	.nsdiv = 0 },	/* 600   KHz */
+	{ .mdiv = 0x02, .pe = 0x3d33,	.sdiv = 0x0,	.nsdiv = 0 },	/* 148.5 Mhz */
+	{ .mdiv = 0x13, .pe = 0x5bcc,	.sdiv = 0x0,	.nsdiv = 1 },	/* 297   Mhz */
+	{ .mdiv = 0x0e, .pe = 0x1025,	.sdiv = 0x0,	.nsdiv = 1 },	/* 333   Mhz */
+	{ .mdiv = 0x0b, .pe = 0x715f,	.sdiv = 0x0,	.nsdiv = 1 },	/* 350   Mhz */
+};
+
+struct clkgen_quadfs_data {
+	bool reset_present;
+	bool bwfilter_present;
+	bool lockstatus_present;
+	bool nsdiv_present;
+	struct clkgen_field ndiv;
+	struct clkgen_field ref_bw;
+	struct clkgen_field nreset;
+	struct clkgen_field npda;
+	struct clkgen_field lock_status;
+
+	struct clkgen_field nsb[QUADFS_MAX_CHAN];
+	struct clkgen_field en[QUADFS_MAX_CHAN];
+	struct clkgen_field mdiv[QUADFS_MAX_CHAN];
+	struct clkgen_field pe[QUADFS_MAX_CHAN];
+	struct clkgen_field sdiv[QUADFS_MAX_CHAN];
+	struct clkgen_field nsdiv[QUADFS_MAX_CHAN];
+
+	const struct clk_ops *pll_ops;
+	struct stm_fs *rtbl;
+	u8 rtbl_cnt;
+	int  (*get_rate)(unsigned long , struct stm_fs *,
+			unsigned long *);
+};
+
+static const struct clk_ops st_quadfs_pll_c65_ops;
+static const struct clk_ops st_quadfs_pll_c32_ops;
+static const struct clk_ops st_quadfs_fs216c65_ops;
+static const struct clk_ops st_quadfs_fs432c65_ops;
+static const struct clk_ops st_quadfs_fs660c32_ops;
+
+static int clk_fs216c65_get_rate(unsigned long, struct stm_fs *,
+		unsigned long *);
+static int clk_fs432c65_get_rate(unsigned long, struct stm_fs *,
+		unsigned long *);
+static int clk_fs660c32_dig_get_rate(unsigned long, struct stm_fs *,
+		unsigned long *);
+/*
+ * Values for all of the standalone instances of this clock
+ * generator found in STiH415 and STiH416 SYSCFG register banks. Note
+ * that the individual channel standby control bits (nsb) are in the
+ * first register along with the PLL control bits.
+ */
+static struct clkgen_quadfs_data st_fs216c65_416 = {
+	/* 416 specific */
+	.npda	= CLKGEN_FIELD(0x0, 0x1, 14),
+	.nsb	= { CLKGEN_FIELD(0x0, 0x1, 10),
+		    CLKGEN_FIELD(0x0, 0x1, 11),
+		    CLKGEN_FIELD(0x0, 0x1, 12),
+		    CLKGEN_FIELD(0x0, 0x1, 13) },
+	.nsdiv_present = true,
+	.nsdiv	= { CLKGEN_FIELD(0x0, 0x1, 18),
+		    CLKGEN_FIELD(0x0, 0x1, 19),
+		    CLKGEN_FIELD(0x0, 0x1, 20),
+		    CLKGEN_FIELD(0x0, 0x1, 21) },
+	.mdiv	= { CLKGEN_FIELD(0x4, 0x1f, 0),
+		    CLKGEN_FIELD(0x14, 0x1f, 0),
+		    CLKGEN_FIELD(0x24, 0x1f, 0),
+		    CLKGEN_FIELD(0x34, 0x1f, 0) },
+	.en	= { CLKGEN_FIELD(0x10, 0x1, 0),
+		    CLKGEN_FIELD(0x20, 0x1, 0),
+		    CLKGEN_FIELD(0x30, 0x1, 0),
+		    CLKGEN_FIELD(0x40, 0x1, 0) },
+	.ndiv	= CLKGEN_FIELD(0x0, 0x1, 15),
+	.bwfilter_present = true,
+	.ref_bw = CLKGEN_FIELD(0x0, 0x3, 16),
+	.pe	= { CLKGEN_FIELD(0x8, 0xffff, 0),
+		    CLKGEN_FIELD(0x18, 0xffff, 0),
+		    CLKGEN_FIELD(0x28, 0xffff, 0),
+		    CLKGEN_FIELD(0x38, 0xffff, 0) },
+	.sdiv	= { CLKGEN_FIELD(0xC, 0x7, 0),
+		    CLKGEN_FIELD(0x1C, 0x7, 0),
+		    CLKGEN_FIELD(0x2C, 0x7, 0),
+		    CLKGEN_FIELD(0x3C, 0x7, 0) },
+	.pll_ops	= &st_quadfs_pll_c65_ops,
+	.rtbl		= fs216c65_rtbl,
+	.rtbl_cnt	= ARRAY_SIZE(fs216c65_rtbl),
+	.get_rate	= clk_fs216c65_get_rate,
+};
+
+static struct clkgen_quadfs_data st_fs432c65_416 = {
+	.npda	= CLKGEN_FIELD(0x0, 0x1, 14),
+	.nsb	= { CLKGEN_FIELD(0x0, 0x1, 10),
+		    CLKGEN_FIELD(0x0, 0x1, 11),
+		    CLKGEN_FIELD(0x0, 0x1, 12),
+		    CLKGEN_FIELD(0x0, 0x1, 13) },
+	.nsdiv_present = true,
+	.nsdiv	= { CLKGEN_FIELD(0x0, 0x1, 18),
+		   CLKGEN_FIELD(0x0, 0x1, 19),
+		   CLKGEN_FIELD(0x0, 0x1, 20),
+		   CLKGEN_FIELD(0x0, 0x1, 21) },
+	.mdiv	= { CLKGEN_FIELD(0x4, 0x1f, 0),
+		    CLKGEN_FIELD(0x14, 0x1f, 0),
+		    CLKGEN_FIELD(0x24, 0x1f, 0),
+		    CLKGEN_FIELD(0x34, 0x1f, 0) },
+	.en	= { CLKGEN_FIELD(0x10, 0x1, 0),
+		    CLKGEN_FIELD(0x20, 0x1, 0),
+		    CLKGEN_FIELD(0x30, 0x1, 0),
+		    CLKGEN_FIELD(0x40, 0x1, 0) },
+	.ndiv	= CLKGEN_FIELD(0x0, 0x1, 15),
+	.bwfilter_present = true,
+	.ref_bw = CLKGEN_FIELD(0x0, 0x3, 16),
+	.pe	= { CLKGEN_FIELD(0x8, 0xffff, 0),
+		    CLKGEN_FIELD(0x18, 0xffff, 0),
+		    CLKGEN_FIELD(0x28, 0xffff, 0),
+		    CLKGEN_FIELD(0x38, 0xffff, 0) },
+	.sdiv	= { CLKGEN_FIELD(0xC, 0x7, 0),
+		    CLKGEN_FIELD(0x1C, 0x7, 0),
+		    CLKGEN_FIELD(0x2C, 0x7, 0),
+		    CLKGEN_FIELD(0x3C, 0x7, 0) },
+	.pll_ops	= &st_quadfs_pll_c65_ops,
+	.rtbl		= fs432c65_rtbl,
+	.rtbl_cnt	= ARRAY_SIZE(fs432c65_rtbl),
+	.get_rate	= clk_fs432c65_get_rate,
+};
+
+static struct clkgen_quadfs_data st_fs660c32_E_416 = {
+	.npda	= CLKGEN_FIELD(0x0, 0x1, 14),
+	.nsb	= { CLKGEN_FIELD(0x0, 0x1, 10),
+		    CLKGEN_FIELD(0x0, 0x1, 11),
+		    CLKGEN_FIELD(0x0, 0x1, 12),
+		    CLKGEN_FIELD(0x0, 0x1, 13) },
+	.nsdiv_present = true,
+	.nsdiv	= { CLKGEN_FIELD(0x0, 0x1, 18),
+		    CLKGEN_FIELD(0x0, 0x1, 19),
+		    CLKGEN_FIELD(0x0, 0x1, 20),
+		    CLKGEN_FIELD(0x0, 0x1, 21) },
+	.mdiv	= { CLKGEN_FIELD(0x4, 0x1f, 0),
+		    CLKGEN_FIELD(0x14, 0x1f, 0),
+		    CLKGEN_FIELD(0x24, 0x1f, 0),
+		    CLKGEN_FIELD(0x34, 0x1f, 0) },
+	.en	= { CLKGEN_FIELD(0x10, 0x1, 0),
+		    CLKGEN_FIELD(0x20, 0x1, 0),
+		    CLKGEN_FIELD(0x30, 0x1, 0),
+		    CLKGEN_FIELD(0x40, 0x1, 0) },
+	.ndiv	= CLKGEN_FIELD(0x0, 0x7, 15),
+	.pe	= { CLKGEN_FIELD(0x8, 0x7fff, 0),
+		    CLKGEN_FIELD(0x18, 0x7fff, 0),
+		    CLKGEN_FIELD(0x28, 0x7fff, 0),
+		    CLKGEN_FIELD(0x38, 0x7fff, 0) },
+	.sdiv	= { CLKGEN_FIELD(0xC, 0xf, 0),
+		    CLKGEN_FIELD(0x1C, 0xf, 0),
+		    CLKGEN_FIELD(0x2C, 0xf, 0),
+		    CLKGEN_FIELD(0x3C, 0xf, 0) },
+	.lockstatus_present = true,
+	.lock_status = CLKGEN_FIELD(0xAC, 0x1, 0),
+	.pll_ops	= &st_quadfs_pll_c32_ops,
+	.rtbl		= fs660c32_rtbl,
+	.rtbl_cnt	= ARRAY_SIZE(fs660c32_rtbl),
+	.get_rate	= clk_fs660c32_dig_get_rate,
+};
+
+static struct clkgen_quadfs_data st_fs660c32_F_416 = {
+	.npda	= CLKGEN_FIELD(0x0, 0x1, 14),
+	.nsb	= { CLKGEN_FIELD(0x0, 0x1, 10),
+		    CLKGEN_FIELD(0x0, 0x1, 11),
+		    CLKGEN_FIELD(0x0, 0x1, 12),
+		    CLKGEN_FIELD(0x0, 0x1, 13) },
+	.nsdiv_present = true,
+	.nsdiv	= { CLKGEN_FIELD(0x0, 0x1, 18),
+		    CLKGEN_FIELD(0x0, 0x1, 19),
+		    CLKGEN_FIELD(0x0, 0x1, 20),
+		    CLKGEN_FIELD(0x0, 0x1, 21) },
+	.mdiv	= { CLKGEN_FIELD(0x4, 0x1f, 0),
+		    CLKGEN_FIELD(0x14, 0x1f, 0),
+		    CLKGEN_FIELD(0x24, 0x1f, 0),
+		    CLKGEN_FIELD(0x34, 0x1f, 0) },
+	.en	= { CLKGEN_FIELD(0x10, 0x1, 0),
+		    CLKGEN_FIELD(0x20, 0x1, 0),
+		    CLKGEN_FIELD(0x30, 0x1, 0),
+		    CLKGEN_FIELD(0x40, 0x1, 0) },
+	.ndiv	= CLKGEN_FIELD(0x0, 0x7, 15),
+	.pe	= { CLKGEN_FIELD(0x8, 0x7fff, 0),
+		    CLKGEN_FIELD(0x18, 0x7fff, 0),
+		    CLKGEN_FIELD(0x28, 0x7fff, 0),
+		    CLKGEN_FIELD(0x38, 0x7fff, 0) },
+	.sdiv	= { CLKGEN_FIELD(0xC, 0xf, 0),
+		    CLKGEN_FIELD(0x1C, 0xf, 0),
+		    CLKGEN_FIELD(0x2C, 0xf, 0),
+		    CLKGEN_FIELD(0x3C, 0xf, 0) },
+	.lockstatus_present = true,
+	.lock_status = CLKGEN_FIELD(0xEC, 0x1, 0),
+	.pll_ops	= &st_quadfs_pll_c32_ops,
+	.rtbl		= fs660c32_rtbl,
+	.rtbl_cnt	= ARRAY_SIZE(fs660c32_rtbl),
+	.get_rate	= clk_fs660c32_dig_get_rate,
+};
+
+/**
+ * DOC: A Frequency Synthesizer that multiples its input clock by a fixed factor
+ *
+ * Traits of this clock:
+ * prepare - clk_(un)prepare only ensures parent is (un)prepared
+ * enable - clk_enable and clk_disable are functional & control the Fsyn
+ * rate - inherits rate from parent. set_rate/round_rate/recalc_rate
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+/**
+ * struct st_clk_quadfs_pll - A pll which outputs a fixed multiplier of
+ *                                  its parent clock, found inside a type of
+ *                                  ST quad channel frequency synthesizer block
+ *
+ * @hw: handle between common and hardware-specific interfaces.
+ * @ndiv: regmap field for the ndiv control.
+ * @regs_base: base address of the configuration registers.
+ * @lock: spinlock.
+ *
+ */
+struct st_clk_quadfs_pll {
+	struct clk_hw	hw;
+	void __iomem	*regs_base;
+	spinlock_t	*lock;
+	struct clkgen_quadfs_data *data;
+	u32 ndiv;
+};
+
+#define to_quadfs_pll(_hw) container_of(_hw, struct st_clk_quadfs_pll, hw)
+
+static int quadfs_pll_enable(struct clk_hw *hw)
+{
+	struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
+	unsigned long flags = 0, timeout = jiffies + msecs_to_jiffies(10);
+
+	if (pll->lock)
+		spin_lock_irqsave(pll->lock, flags);
+
+	/*
+	 * Bring block out of reset if we have reset control.
+	 */
+	if (pll->data->reset_present)
+		CLKGEN_WRITE(pll, nreset, 1);
+
+	/*
+	 * Use a fixed input clock noise bandwidth filter for the moment
+	 */
+	if (pll->data->bwfilter_present)
+		CLKGEN_WRITE(pll, ref_bw, PLL_BW_GOODREF);
+
+
+	CLKGEN_WRITE(pll, ndiv, pll->ndiv);
+
+	/*
+	 * Power up the PLL
+	 */
+	CLKGEN_WRITE(pll, npda, 1);
+
+	if (pll->lock)
+		spin_unlock_irqrestore(pll->lock, flags);
+
+	if (pll->data->lockstatus_present)
+		while (!CLKGEN_READ(pll, lock_status)) {
+			if (time_after(jiffies, timeout))
+				return -ETIMEDOUT;
+			cpu_relax();
+		}
+
+	return 0;
+}
+
+static void quadfs_pll_disable(struct clk_hw *hw)
+{
+	struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
+	unsigned long flags = 0;
+
+	if (pll->lock)
+		spin_lock_irqsave(pll->lock, flags);
+
+	/*
+	 * Powerdown the PLL and then put block into soft reset if we have
+	 * reset control.
+	 */
+	CLKGEN_WRITE(pll, npda, 0);
+
+	if (pll->data->reset_present)
+		CLKGEN_WRITE(pll, nreset, 0);
+
+	if (pll->lock)
+		spin_unlock_irqrestore(pll->lock, flags);
+}
+
+static int quadfs_pll_is_enabled(struct clk_hw *hw)
+{
+	struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
+	u32 npda = CLKGEN_READ(pll, npda);
+
+	return !!npda;
+}
+
+int clk_fs660c32_vco_get_rate(unsigned long input, struct stm_fs *fs,
+			   unsigned long *rate)
+{
+	unsigned long nd = fs->ndiv + 16; /* ndiv value */
+
+	*rate = input * nd;
+
+	return 0;
+}
+
+static unsigned long quadfs_pll_fs660c32_recalc_rate(struct clk_hw *hw,
+					unsigned long parent_rate)
+{
+	struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
+	unsigned long rate = 0;
+	struct stm_fs params;
+
+	params.ndiv = CLKGEN_READ(pll, ndiv);
+	if (clk_fs660c32_vco_get_rate(parent_rate, &params, &rate))
+		pr_err("%s:%s error calculating rate\n",
+		       __clk_get_name(hw->clk), __func__);
+
+	pll->ndiv = params.ndiv;
+
+	return rate;
+}
+
+int clk_fs660c32_vco_get_params(unsigned long input,
+				unsigned long output, struct stm_fs *fs)
+{
+/* Formula
+   VCO frequency = (fin x ndiv) / pdiv
+   ndiv = VCOfreq * pdiv / fin
+   */
+	unsigned long pdiv = 1, n;
+
+	/* Output clock range: 384Mhz to 660Mhz */
+	if (output < 384000000 || output > 660000000)
+		return -EINVAL;
+
+	if (input > 40000000)
+		/* This means that PDIV would be 2 instead of 1.
+		   Not supported today. */
+		return -EINVAL;
+
+	input /= 1000;
+	output /= 1000;
+
+	n = output * pdiv / input;
+	if (n < 16)
+		n = 16;
+	fs->ndiv = n - 16; /* Converting formula value to reg value */
+
+	return 0;
+}
+
+static long quadfs_pll_fs660c32_round_rate(struct clk_hw *hw, unsigned long rate
+		, unsigned long *prate)
+{
+	struct stm_fs params;
+
+	if (!clk_fs660c32_vco_get_params(*prate, rate, &params))
+		clk_fs660c32_vco_get_rate(*prate, &params, &rate);
+
+	pr_debug("%s: %s new rate %ld [sdiv=0x%x,md=0x%x,pe=0x%x,nsdiv3=%u]\n",
+		 __func__, __clk_get_name(hw->clk),
+		 rate, (unsigned int)params.sdiv,
+		 (unsigned int)params.mdiv,
+		 (unsigned int)params.pe, (unsigned int)params.nsdiv);
+
+	return rate;
+}
+
+static int quadfs_pll_fs660c32_set_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long parent_rate)
+{
+	struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
+	struct stm_fs params;
+	long hwrate = 0;
+	unsigned long flags = 0;
+
+	if (!rate || !parent_rate)
+		return -EINVAL;
+
+	if (!clk_fs660c32_vco_get_params(parent_rate, rate, &params))
+		clk_fs660c32_vco_get_rate(parent_rate, &params, &hwrate);
+
+	pr_debug("%s: %s new rate %ld [ndiv=0x%x]\n",
+		 __func__, __clk_get_name(hw->clk),
+		 hwrate, (unsigned int)params.ndiv);
+
+	if (!hwrate)
+		return -EINVAL;
+
+	pll->ndiv = params.ndiv;
+
+	if (pll->lock)
+		spin_lock_irqsave(pll->lock, flags);
+
+	CLKGEN_WRITE(pll, ndiv, pll->ndiv);
+
+	if (pll->lock)
+		spin_unlock_irqrestore(pll->lock, flags);
+
+	return 0;
+}
+
+static const struct clk_ops st_quadfs_pll_c65_ops = {
+	.enable		= quadfs_pll_enable,
+	.disable	= quadfs_pll_disable,
+	.is_enabled	= quadfs_pll_is_enabled,
+};
+
+static const struct clk_ops st_quadfs_pll_c32_ops = {
+	.enable		= quadfs_pll_enable,
+	.disable	= quadfs_pll_disable,
+	.is_enabled	= quadfs_pll_is_enabled,
+	.recalc_rate	= quadfs_pll_fs660c32_recalc_rate,
+	.round_rate	= quadfs_pll_fs660c32_round_rate,
+	.set_rate	= quadfs_pll_fs660c32_set_rate,
+};
+
+static struct clk * __init st_clk_register_quadfs_pll(
+		const char *name, const char *parent_name,
+		struct clkgen_quadfs_data *quadfs, void __iomem *reg,
+		spinlock_t *lock)
+{
+	struct st_clk_quadfs_pll *pll;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	/*
+	 * Sanity check required pointers.
+	 */
+	if (WARN_ON(!name || !parent_name))
+		return ERR_PTR(-EINVAL);
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = quadfs->pll_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	pll->data = quadfs;
+	pll->regs_base = reg;
+	pll->lock = lock;
+	pll->hw.init = &init;
+
+	clk = clk_register(NULL, &pll->hw);
+
+	if (IS_ERR(clk))
+		kfree(pll);
+
+	return clk;
+}
+
+/**
+ * DOC: A digital frequency synthesizer
+ *
+ * Traits of this clock:
+ * prepare - clk_(un)prepare only ensures parent is (un)prepared
+ * enable - clk_enable and clk_disable are functional
+ * rate - set rate is functional
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+/**
+ * struct st_clk_quadfs_fsynth - One clock output from a four channel digital
+ *                                  frequency synthesizer (fsynth) block.
+ *
+ * @hw: handle between common and hardware-specific interfaces
+ *
+ * @nsb: regmap field in the output control register for the digital
+ *       standby of this fsynth channel. This control is active low so
+ *       the channel is in standby when the control bit is cleared.
+ *
+ * @nsdiv: regmap field in the output control register for
+ *          for the optional divide by 3 of this fsynth channel. This control
+ *          is active low so the divide by 3 is active when the control bit is
+ *          cleared and the divide is bypassed when the bit is set.
+ */
+struct st_clk_quadfs_fsynth {
+	struct clk_hw	hw;
+	void __iomem	*regs_base;
+	spinlock_t	*lock;
+	struct clkgen_quadfs_data *data;
+
+	u32 chan;
+	/*
+	 * Cached hardware values from set_rate so we can program the
+	 * hardware in enable. There are two reasons for this:
+	 *
+	 *  1. The registers may not be writable until the parent has been
+	 *     enabled.
+	 *
+	 *  2. It restores the clock rate when a driver does an enable
+	 *     on PM restore, after a suspend to RAM has lost the hardware
+	 *     setup.
+	 */
+	u32 md;
+	u32 pe;
+	u32 sdiv;
+	u32 nsdiv;
+};
+
+#define to_quadfs_fsynth(_hw) \
+	container_of(_hw, struct st_clk_quadfs_fsynth, hw)
+
+static void quadfs_fsynth_program_enable(struct st_clk_quadfs_fsynth *fs)
+{
+	/*
+	 * Pulse the program enable register lsb to make the hardware take
+	 * notice of the new md/pe values with a glitchless transition.
+	 */
+	CLKGEN_WRITE(fs, en[fs->chan], 1);
+	CLKGEN_WRITE(fs, en[fs->chan], 0);
+}
+
+static void quadfs_fsynth_program_rate(struct st_clk_quadfs_fsynth *fs)
+{
+	unsigned long flags = 0;
+
+	/*
+	 * Ensure the md/pe parameters are ignored while we are
+	 * reprogramming them so we can get a glitchless change
+	 * when fine tuning the speed of a running clock.
+	 */
+	CLKGEN_WRITE(fs, en[fs->chan], 0);
+
+	CLKGEN_WRITE(fs, mdiv[fs->chan], fs->md);
+	CLKGEN_WRITE(fs, pe[fs->chan], fs->pe);
+	CLKGEN_WRITE(fs, sdiv[fs->chan], fs->sdiv);
+
+	if (fs->lock)
+		spin_lock_irqsave(fs->lock, flags);
+
+	if (fs->data->nsdiv_present)
+		CLKGEN_WRITE(fs, nsdiv[fs->chan], fs->nsdiv);
+
+	if (fs->lock)
+		spin_unlock_irqrestore(fs->lock, flags);
+}
+
+static int quadfs_fsynth_enable(struct clk_hw *hw)
+{
+	struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
+	unsigned long flags = 0;
+
+	pr_debug("%s: %s\n", __func__, __clk_get_name(hw->clk));
+
+	quadfs_fsynth_program_rate(fs);
+
+	if (fs->lock)
+		spin_lock_irqsave(fs->lock, flags);
+
+	CLKGEN_WRITE(fs, nsb[fs->chan], 1);
+
+	if (fs->lock)
+		spin_unlock_irqrestore(fs->lock, flags);
+
+	quadfs_fsynth_program_enable(fs);
+
+	return 0;
+}
+
+static void quadfs_fsynth_disable(struct clk_hw *hw)
+{
+	struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
+	unsigned long flags = 0;
+
+	pr_debug("%s: %s\n", __func__, __clk_get_name(hw->clk));
+
+	if (fs->lock)
+		spin_lock_irqsave(fs->lock, flags);
+
+	CLKGEN_WRITE(fs, nsb[fs->chan], 0);
+
+	if (fs->lock)
+		spin_unlock_irqrestore(fs->lock, flags);
+}
+
+static int quadfs_fsynth_is_enabled(struct clk_hw *hw)
+{
+	struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
+	u32 nsb = CLKGEN_READ(fs, nsb[fs->chan]);
+
+	pr_debug("%s: %s enable bit = 0x%x\n",
+		 __func__, __clk_get_name(hw->clk), nsb);
+
+	return !!nsb;
+}
+
+#define P15			(uint64_t)(1 << 15)
+
+static int clk_fs216c65_get_rate(unsigned long input, struct stm_fs *fs,
+		unsigned long *rate)
+{
+	uint64_t res;
+	unsigned long ns;
+	unsigned long nd = 8; /* ndiv stuck at 0 => val = 8 */
+	unsigned long s;
+	long m;
+
+	m = fs->mdiv - 32;
+	s = 1 << (fs->sdiv + 1);
+	ns = (fs->nsdiv ? 1 : 3);
+
+	res = (uint64_t)(s * ns * P15 * (uint64_t)(m + 33));
+	res = res - (s * ns * fs->pe);
+	*rate = div64_u64(P15 * nd * input * 32, res);
+
+	return 0;
+}
+
+static int clk_fs432c65_get_rate(unsigned long input, struct stm_fs *fs,
+		unsigned long *rate)
+{
+	uint64_t res;
+	unsigned long nd = 16; /* ndiv value; stuck at 0 (30Mhz input) */
+	long m;
+	unsigned long sd;
+	unsigned long ns;
+
+	m = fs->mdiv - 32;
+	sd = 1 << (fs->sdiv + 1);
+	ns = (fs->nsdiv ? 1 : 3);
+
+	res = (uint64_t)(sd * ns * P15 * (uint64_t)(m + 33));
+	res = res - (sd * ns * fs->pe);
+	*rate = div64_u64(P15 * nd * input * 32, res);
+
+	return 0;
+}
+
+#define P20		(uint64_t)(1 << 20)
+
+static int clk_fs660c32_dig_get_rate(unsigned long input,
+				struct stm_fs *fs, unsigned long *rate)
+{
+	unsigned long s = (1 << fs->sdiv);
+	unsigned long ns;
+	uint64_t res;
+
+	/*
+	 * 'nsdiv' is a register value ('BIN') which is translated
+	 * to a decimal value according to following rules.
+	 *
+	 *     nsdiv      ns.dec
+	 *       0        3
+	 *       1        1
+	 */
+	ns = (fs->nsdiv == 1) ? 1 : 3;
+
+	res = (P20 * (32 + fs->mdiv) + 32 * fs->pe) * s * ns;
+	*rate = (unsigned long)div64_u64(input * P20 * 32, res);
+
+	return 0;
+}
+
+static int quadfs_fsynt_get_hw_value_for_recalc(struct st_clk_quadfs_fsynth *fs,
+		struct stm_fs *params)
+{
+	/*
+	 * Get the initial hardware values for recalc_rate
+	 */
+	params->mdiv	= CLKGEN_READ(fs, mdiv[fs->chan]);
+	params->pe	= CLKGEN_READ(fs, pe[fs->chan]);
+	params->sdiv	= CLKGEN_READ(fs, sdiv[fs->chan]);
+
+	if (fs->data->nsdiv_present)
+		params->nsdiv = CLKGEN_READ(fs, nsdiv[fs->chan]);
+	else
+		params->nsdiv = 1;
+
+	/*
+	 * If All are NULL then assume no clock rate is programmed.
+	 */
+	if (!params->mdiv && !params->pe && !params->sdiv)
+		return 1;
+
+	fs->md = params->mdiv;
+	fs->pe = params->pe;
+	fs->sdiv = params->sdiv;
+	fs->nsdiv = params->nsdiv;
+
+	return 0;
+}
+
+static long quadfs_find_best_rate(struct clk_hw *hw, unsigned long drate,
+				unsigned long prate, struct stm_fs *params)
+{
+	struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
+	int (*clk_fs_get_rate)(unsigned long ,
+				struct stm_fs *, unsigned long *);
+	struct stm_fs prev_params;
+	unsigned long prev_rate, rate = 0;
+	unsigned long diff_rate, prev_diff_rate = ~0;
+	int index;
+
+	clk_fs_get_rate = fs->data->get_rate;
+
+	for (index = 0; index < fs->data->rtbl_cnt; index++) {
+		prev_rate = rate;
+
+		*params = fs->data->rtbl[index];
+		prev_params = *params;
+
+		clk_fs_get_rate(prate, &fs->data->rtbl[index], &rate);
+
+		diff_rate = abs(drate - rate);
+
+		if (diff_rate > prev_diff_rate) {
+			rate = prev_rate;
+			*params = prev_params;
+			break;
+		}
+
+		prev_diff_rate = diff_rate;
+
+		if (drate == rate)
+			return rate;
+	}
+
+
+	if (index == fs->data->rtbl_cnt)
+		*params = prev_params;
+
+	return rate;
+}
+
+static unsigned long quadfs_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
+	unsigned long rate = 0;
+	struct stm_fs params;
+	int (*clk_fs_get_rate)(unsigned long ,
+				struct stm_fs *, unsigned long *);
+
+	clk_fs_get_rate = fs->data->get_rate;
+
+	if (quadfs_fsynt_get_hw_value_for_recalc(fs, &params))
+		return 0;
+
+	if (clk_fs_get_rate(parent_rate, &params, &rate)) {
+		pr_err("%s:%s error calculating rate\n",
+		       __clk_get_name(hw->clk), __func__);
+	}
+
+	pr_debug("%s:%s rate %lu\n", __clk_get_name(hw->clk), __func__, rate);
+
+	return rate;
+}
+
+static long quadfs_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *prate)
+{
+	struct stm_fs params;
+
+	rate = quadfs_find_best_rate(hw, rate, *prate, &params);
+
+	pr_debug("%s: %s new rate %ld [sdiv=0x%x,md=0x%x,pe=0x%x,nsdiv3=%u]\n",
+		 __func__, __clk_get_name(hw->clk),
+		 rate, (unsigned int)params.sdiv, (unsigned int)params.mdiv,
+			 (unsigned int)params.pe, (unsigned int)params.nsdiv);
+
+	return rate;
+}
+
+
+static void quadfs_program_and_enable(struct st_clk_quadfs_fsynth *fs,
+		struct stm_fs *params)
+{
+	fs->md = params->mdiv;
+	fs->pe = params->pe;
+	fs->sdiv = params->sdiv;
+	fs->nsdiv = params->nsdiv;
+
+	/*
+	 * In some integrations you can only change the fsynth programming when
+	 * the parent entity containing it is enabled.
+	 */
+	quadfs_fsynth_program_rate(fs);
+	quadfs_fsynth_program_enable(fs);
+}
+
+static int quadfs_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
+	struct stm_fs params;
+	long hwrate;
+	int uninitialized_var(i);
+
+	if (!rate || !parent_rate)
+		return -EINVAL;
+
+	memset(&params, 0, sizeof(struct stm_fs));
+
+	hwrate = quadfs_find_best_rate(hw, rate, parent_rate, &params);
+	if (!hwrate)
+		return -EINVAL;
+
+	quadfs_program_and_enable(fs, &params);
+
+	return 0;
+}
+
+
+
+static const struct clk_ops st_quadfs_ops = {
+	.enable		= quadfs_fsynth_enable,
+	.disable	= quadfs_fsynth_disable,
+	.is_enabled	= quadfs_fsynth_is_enabled,
+	.round_rate	= quadfs_round_rate,
+	.set_rate	= quadfs_set_rate,
+	.recalc_rate	= quadfs_recalc_rate,
+};
+
+static struct clk * __init st_clk_register_quadfs_fsynth(
+		const char *name, const char *parent_name,
+		struct clkgen_quadfs_data *quadfs, void __iomem *reg, u32 chan,
+		spinlock_t *lock)
+{
+	struct st_clk_quadfs_fsynth *fs;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	/*
+	 * Sanity check required pointers, note that nsdiv3 is optional.
+	 */
+	if (WARN_ON(!name || !parent_name))
+		return ERR_PTR(-EINVAL);
+
+	fs = kzalloc(sizeof(*fs), GFP_KERNEL);
+	if (!fs)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &st_quadfs_ops;
+	init.flags = CLK_GET_RATE_NOCACHE | CLK_IS_BASIC;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	fs->data = quadfs;
+	fs->regs_base = reg;
+	fs->chan = chan;
+	fs->lock = lock;
+	fs->hw.init = &init;
+
+	clk = clk_register(NULL, &fs->hw);
+
+	if (IS_ERR(clk))
+		kfree(fs);
+
+	return clk;
+}
+
+static struct of_device_id quadfs_of_match[] = {
+	{
+		.compatible = "st,stih416-quadfs216",
+		.data = (void *)&st_fs216c65_416
+	},
+	{
+		.compatible = "st,stih416-quadfs432",
+		.data = (void *)&st_fs432c65_416
+	},
+	{
+		.compatible = "st,stih416-quadfs660-E",
+		.data = (void *)&st_fs660c32_E_416
+	},
+	{
+		.compatible = "st,stih416-quadfs660-F",
+		.data = (void *)&st_fs660c32_F_416
+	},
+	{}
+};
+
+static void __init st_of_create_quadfs_fsynths(
+		struct device_node *np, const char *pll_name,
+		struct clkgen_quadfs_data *quadfs, void __iomem *reg,
+		spinlock_t *lock)
+{
+	struct clk_onecell_data *clk_data;
+	int fschan;
+
+	clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
+	if (!clk_data)
+		return;
+
+	clk_data->clk_num = QUADFS_MAX_CHAN;
+	clk_data->clks = kzalloc(QUADFS_MAX_CHAN * sizeof(struct clk *),
+				 GFP_KERNEL);
+
+	if (!clk_data->clks) {
+		kfree(clk_data);
+		return;
+	}
+
+	for (fschan = 0; fschan < QUADFS_MAX_CHAN; fschan++) {
+		struct clk *clk;
+		const char *clk_name;
+
+		if (of_property_read_string_index(np, "clock-output-names",
+						  fschan, &clk_name)) {
+			break;
+		}
+
+		/*
+		 * If we read an empty clock name then the channel is unused
+		 */
+		if (*clk_name == '\0')
+			continue;
+
+		clk = st_clk_register_quadfs_fsynth(clk_name, pll_name,
+				quadfs, reg, fschan, lock);
+
+		/*
+		 * If there was an error registering this clock output, clean
+		 * up and move on to the next one.
+		 */
+		if (!IS_ERR(clk)) {
+			clk_data->clks[fschan] = clk;
+			pr_debug("%s: parent %s rate %u\n",
+				__clk_get_name(clk),
+				__clk_get_name(clk_get_parent(clk)),
+				(unsigned int)clk_get_rate(clk));
+		}
+	}
+
+	of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
+}
+
+static void __init st_of_quadfs_setup(struct device_node *np)
+{
+	const struct of_device_id *match;
+	struct clk *clk;
+	const char *pll_name, *clk_parent_name;
+	void __iomem *reg;
+	spinlock_t *lock;
+
+	match = of_match_node(quadfs_of_match, np);
+	if (WARN_ON(!match))
+		return;
+
+	reg = of_iomap(np, 0);
+	if (!reg)
+		return;
+
+	clk_parent_name = of_clk_get_parent_name(np, 0);
+	if (!clk_parent_name)
+		return;
+
+	pll_name = kasprintf(GFP_KERNEL, "%s.pll", np->name);
+	if (!pll_name)
+		return;
+
+	lock = kzalloc(sizeof(*lock), GFP_KERNEL);
+	if (!lock)
+		goto err_exit;
+
+	spin_lock_init(lock);
+
+	clk = st_clk_register_quadfs_pll(pll_name, clk_parent_name,
+			(struct clkgen_quadfs_data *) match->data, reg, lock);
+	if (IS_ERR(clk))
+		goto err_exit;
+	else
+		pr_debug("%s: parent %s rate %u\n",
+			__clk_get_name(clk),
+			__clk_get_name(clk_get_parent(clk)),
+			(unsigned int)clk_get_rate(clk));
+
+	st_of_create_quadfs_fsynths(np, pll_name,
+				    (struct clkgen_quadfs_data *)match->data,
+				    reg, lock);
+
+err_exit:
+	kfree(pll_name); /* No longer need local copy of the PLL name */
+}
+CLK_OF_DECLARE(quadfs, "st,quadfs", st_of_quadfs_setup);