103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* linux/arch/arm/common/icst307.c
|
|
*
|
|
* Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
|
|
*
|
|
* 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);
|