ARM/clk: move the ICST library to drivers/clk

This moves the ICST clock divider helper library from
arch/arm/common to drivers/clk/versatile so it is maintained
with the other clock drivers.

We keep the structure as a helper library intact and do not
fuse it with the clk-icst.c Versatile ICST clock driver: there
may be other users out there that need to use this library for
their clocking, and then it will be helpful to keep the
library contained. (The icst.[c|h] files could just be moved
to drivers/clk/lib or a similar location to share the library.)

Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/clk/versatile/Kconfig

@@ -1,3 +1,6 @@
+config ICST
+	bool
+
 config COMMON_CLK_VERSATILE
 	bool "Clock driver for ARM Reference designs"
 	depends on ARCH_INTEGRATOR || ARCH_REALVIEW || \

drivers/clk/versatile/Makefile

@@ -1,5 +1,5 @@
 # Makefile for Versatile-specific clocks
-obj-$(CONFIG_ICST)		+= clk-icst.o clk-versatile.o
+obj-$(CONFIG_ICST)		+= icst.o clk-icst.o clk-versatile.o
 obj-$(CONFIG_INTEGRATOR_IMPD1)	+= clk-impd1.o
 obj-$(CONFIG_ARCH_REALVIEW)	+= clk-realview.o
 obj-$(CONFIG_CLK_SP810)		+= clk-sp810.o

drivers/clk/versatile/clk-icst.c

@@ -22,6 +22,7 @@
 #include <linux/regmap.h>
 #include <linux/mfd/syscon.h>
 
+#include "icst.h"
 #include "clk-icst.h"
 
 /* Magic unlocking token used on all Versatile boards */

drivers/clk/versatile/clk-icst.h

@@ -1,5 +1,3 @@
-#include <asm/hardware/icst.h>
-
 /**
  * struct clk_icst_desc - descriptor for the ICST VCO
  * @params: ICST parameters

drivers/clk/versatile/clk-impd1.c

@@ -12,6 +12,7 @@
 #include <linux/io.h>
 #include <linux/platform_data/clk-integrator.h>
 
+#include "icst.h"
 #include "clk-icst.h"
 
 #define IMPD1_OSC1	0x00

drivers/clk/versatile/clk-realview.c

@@ -11,6 +11,7 @@
 #include <linux/io.h>
 #include <linux/clk-provider.h>
 
+#include "icst.h"
 #include "clk-icst.h"
 
 #define REALVIEW_SYS_OSC0_OFFSET             0x0C

drivers/clk/versatile/clk-versatile.c

@@ -12,6 +12,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 
+#include "icst.h"
 #include "clk-icst.h"
 
 #define INTEGRATOR_HDR_LOCK_OFFSET	0x14

drivers/clk/versatile/icst.c

@@ -0,0 +1,105 @@
+/*
+ *  linux/arch/arm/common/icst307.c
+ *
+ *  Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
+ *
+ * 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.
+ *
+ *  Support functions for calculating clocks/divisors for the ICST307
+ *  clock generators.  See http://www.idt.com/ for more information
+ *  on these devices.
+ *
+ *  This is an almost identical implementation to the ICST525 clock generator.
+ *  The s2div and idx2s files are different
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <asm/div64.h>
+#include "icst.h"
+
+/*
+ * Divisors for each OD setting.
+ */
+const unsigned char icst307_s2div[8] = { 10, 2, 8, 4, 5, 7, 3, 6 };
+const unsigned char icst525_s2div[8] = { 10, 2, 8, 4, 5, 7, 9, 6 };
+EXPORT_SYMBOL(icst307_s2div);
+EXPORT_SYMBOL(icst525_s2div);
+
+unsigned long icst_hz(const struct icst_params *p, struct icst_vco vco)
+{
+	u64 dividend = p->ref * 2 * (u64)(vco.v + 8);
+	u32 divisor = (vco.r + 2) * p->s2div[vco.s];
+
+	do_div(dividend, divisor);
+	return (unsigned long)dividend;
+}
+
+EXPORT_SYMBOL(icst_hz);
+
+/*
+ * Ascending divisor S values.
+ */
+const unsigned char icst307_idx2s[8] = { 1, 6, 3, 4, 7, 5, 2, 0 };
+const unsigned char icst525_idx2s[8] = { 1, 3, 4, 7, 5, 2, 6, 0 };
+EXPORT_SYMBOL(icst307_idx2s);
+EXPORT_SYMBOL(icst525_idx2s);
+
+struct icst_vco
+icst_hz_to_vco(const struct icst_params *p, unsigned long freq)
+{
+	struct icst_vco vco = { .s = 1, .v = p->vd_max, .r = p->rd_max };
+	unsigned long f;
+	unsigned int i = 0, rd, best = (unsigned int)-1;
+
+	/*
+	 * First, find the PLL output divisor such
+	 * that the PLL output is within spec.
+	 */
+	do {
+		f = freq * p->s2div[p->idx2s[i]];
+
+		if (f > p->vco_min && f <= p->vco_max)
+			break;
+		i++;
+	} while (i < 8);
+
+	if (i >= 8)
+		return vco;
+
+	vco.s = p->idx2s[i];
+
+	/*
+	 * Now find the closest divisor combination
+	 * which gives a PLL output of 'f'.
+	 */
+	for (rd = p->rd_min; rd <= p->rd_max; rd++) {
+		unsigned long fref_div, f_pll;
+		unsigned int vd;
+		int f_diff;
+
+		fref_div = (2 * p->ref) / rd;
+
+		vd = (f + fref_div / 2) / fref_div;
+		if (vd < p->vd_min || vd > p->vd_max)
+			continue;
+
+		f_pll = fref_div * vd;
+		f_diff = f_pll - f;
+		if (f_diff < 0)
+			f_diff = -f_diff;
+
+		if ((unsigned)f_diff < best) {
+			vco.v = vd - 8;
+			vco.r = rd - 2;
+			if (f_diff == 0)
+				break;
+			best = f_diff;
+		}
+	}
+
+	return vco;
+}
+
+EXPORT_SYMBOL(icst_hz_to_vco);

drivers/clk/versatile/icst.h

@@ -0,0 +1,57 @@
+/*
+ *  Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
+ *
+ * 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.
+ *
+ *  Support functions for calculating clocks/divisors for the ICST
+ *  clock generators.  See http://www.idt.com/ for more information
+ *  on these devices.
+ */
+#ifndef ICST_H
+#define ICST_H
+
+struct icst_params {
+	unsigned long	ref;
+	unsigned long	vco_max;	/* inclusive */
+	unsigned long	vco_min;	/* exclusive */
+	unsigned short	vd_min;		/* inclusive */
+	unsigned short	vd_max;		/* inclusive */
+	unsigned char	rd_min;		/* inclusive */
+	unsigned char	rd_max;		/* inclusive */
+	const unsigned char *s2div;	/* chip specific s2div array */
+	const unsigned char *idx2s;	/* chip specific idx2s array */
+};
+
+struct icst_vco {
+	unsigned short	v;
+	unsigned char	r;
+	unsigned char	s;
+};
+
+unsigned long icst_hz(const struct icst_params *p, struct icst_vco vco);
+struct icst_vco icst_hz_to_vco(const struct icst_params *p, unsigned long freq);
+
+/*
+ * ICST307 VCO frequency must be between 6MHz and 200MHz (3.3 or 5V).
+ * This frequency is pre-output divider.
+ */
+#define ICST307_VCO_MIN	6000000
+#define ICST307_VCO_MAX	200000000
+
+extern const unsigned char icst307_s2div[];
+extern const unsigned char icst307_idx2s[];
+
+/*
+ * ICST525 VCO frequency must be between 10MHz and 200MHz (3V) or 320MHz (5V).
+ * This frequency is pre-output divider.
+ */
+#define ICST525_VCO_MIN		10000000
+#define ICST525_VCO_MAX_3V	200000000
+#define ICST525_VCO_MAX_5V	320000000
+
+extern const unsigned char icst525_s2div[];
+extern const unsigned char icst525_idx2s[];
+
+#endif