1 files changed, 160 insertions, 0 deletions
diff --git a/arch/arm/common/icst525.c b/arch/arm/common/icst525.c
new file mode 100644
index 00000000000..943ef88c037
--- /dev/null
+++ b/arch/arm/common/icst525.c
@@ -0,0 +1,160 @@
+/*
+ *  linux/arch/arm/common/icst525.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 ICST525
+ *  clock generators.  See http://www.icst.com/ for more information
+ *  on these devices.
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include <asm/hardware/icst525.h>
+
+/*
+ * Divisors for each OD setting.
+ */
+static unsigned char s2div[8] = { 10, 2, 8, 4, 5, 7, 9, 6 };
+
+unsigned long icst525_khz(const struct icst525_params *p, struct icst525_vco vco)
+{
+	return p->ref * 2 * (vco.v + 8) / ((vco.r + 2) * s2div[vco.s]);
+}
+
+EXPORT_SYMBOL(icst525_khz);
+
+/*
+ * Ascending divisor S values.
+ */
+static unsigned char idx2s[] = { 1, 3, 4, 7, 5, 2, 6, 0 };
+
+struct icst525_vco
+icst525_khz_to_vco(const struct icst525_params *p, unsigned long freq)
+{
+	struct icst525_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 * s2div[idx2s[i]];
+
+		/*
+		 * f must be between 10MHz and
+		 *  320MHz (5V) or 200MHz (3V)
+		 */
+		if (f > 10000 && f <= p->vco_max)
+			break;
+	} while (i < ARRAY_SIZE(idx2s));
+
+	if (i > ARRAY_SIZE(idx2s))
+		return vco;
+
+	vco.s = 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(icst525_khz_to_vco);
+
+struct icst525_vco
+icst525_ps_to_vco(const struct icst525_params *p, unsigned long period)
+{
+	struct icst525_vco vco = { .s = 1, .v = p->vd_max, .r = p->rd_max };
+	unsigned long f, ps;
+	unsigned int i = 0, rd, best = (unsigned int)-1;
+
+	ps = 1000000000UL / p->vco_max;
+
+	/*
+	 * First, find the PLL output divisor such
+	 * that the PLL output is within spec.
+	 */
+	do {
+		f = period / s2div[idx2s[i]];
+
+		/*
+		 * f must be between 10MHz and
+		 *  320MHz (5V) or 200MHz (3V)
+		 */
+		if (f >= ps && f < 100000)
+			break;
+	} while (i < ARRAY_SIZE(idx2s));
+
+	if (i > ARRAY_SIZE(idx2s))
+		return vco;
+
+	vco.s = idx2s[i];
+
+	ps = 500000000UL / p->ref;
+
+	/*
+	 * 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 f_in_div, f_pll;
+		unsigned int vd;
+		int f_diff;
+
+		f_in_div = ps * rd;
+
+		vd = (f_in_div + f / 2) / f;
+		if (vd < p->vd_min || vd > p->vd_max)
+			continue;
+
+		f_pll = (f_in_div + vd / 2) / 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(icst525_ps_to_vco);