/* * 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 <asm/hardware/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);