tegrakernel/kernel/kernel-4.9/drivers/clk/sunxi-ng/ccu_nkmp.c

167 lines
4.2 KiB
C

/*
* Copyright (C) 2016 Maxime Ripard
* Maxime Ripard <maxime.ripard@free-electrons.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*/
#include <linux/clk-provider.h>
#include <linux/rational.h>
#include "ccu_gate.h"
#include "ccu_nkmp.h"
struct _ccu_nkmp {
unsigned long n, max_n;
unsigned long k, max_k;
unsigned long m, max_m;
unsigned long p, max_p;
};
static void ccu_nkmp_find_best(unsigned long parent, unsigned long rate,
struct _ccu_nkmp *nkmp)
{
unsigned long best_rate = 0;
unsigned long best_n = 0, best_k = 0, best_m = 0, best_p = 0;
unsigned long _n, _k, _m, _p;
for (_k = 1; _k <= nkmp->max_k; _k++) {
for (_p = 1; _p <= nkmp->max_p; _p <<= 1) {
unsigned long tmp_rate;
rational_best_approximation(rate / _k, parent / _p,
nkmp->max_n, nkmp->max_m,
&_n, &_m);
tmp_rate = parent * _n * _k / (_m * _p);
if (tmp_rate > rate)
continue;
if ((rate - tmp_rate) < (rate - best_rate)) {
best_rate = tmp_rate;
best_n = _n;
best_k = _k;
best_m = _m;
best_p = _p;
}
}
}
nkmp->n = best_n;
nkmp->k = best_k;
nkmp->m = best_m;
nkmp->p = best_p;
}
static void ccu_nkmp_disable(struct clk_hw *hw)
{
struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
return ccu_gate_helper_disable(&nkmp->common, nkmp->enable);
}
static int ccu_nkmp_enable(struct clk_hw *hw)
{
struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
return ccu_gate_helper_enable(&nkmp->common, nkmp->enable);
}
static int ccu_nkmp_is_enabled(struct clk_hw *hw)
{
struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
return ccu_gate_helper_is_enabled(&nkmp->common, nkmp->enable);
}
static unsigned long ccu_nkmp_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
unsigned long n, m, k, p;
u32 reg;
reg = readl(nkmp->common.base + nkmp->common.reg);
n = reg >> nkmp->n.shift;
n &= (1 << nkmp->n.width) - 1;
k = reg >> nkmp->k.shift;
k &= (1 << nkmp->k.width) - 1;
m = reg >> nkmp->m.shift;
m &= (1 << nkmp->m.width) - 1;
p = reg >> nkmp->p.shift;
p &= (1 << nkmp->p.width) - 1;
return (parent_rate * (n + 1) * (k + 1) >> p) / (m + 1);
}
static long ccu_nkmp_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
struct _ccu_nkmp _nkmp;
_nkmp.max_n = 1 << nkmp->n.width;
_nkmp.max_k = 1 << nkmp->k.width;
_nkmp.max_m = nkmp->m.max ?: 1 << nkmp->m.width;
_nkmp.max_p = nkmp->p.max ?: 1 << ((1 << nkmp->p.width) - 1);
ccu_nkmp_find_best(*parent_rate, rate, &_nkmp);
return *parent_rate * _nkmp.n * _nkmp.k / (_nkmp.m * _nkmp.p);
}
static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
struct _ccu_nkmp _nkmp;
unsigned long flags;
u32 reg;
_nkmp.max_n = 1 << nkmp->n.width;
_nkmp.max_k = 1 << nkmp->k.width;
_nkmp.max_m = nkmp->m.max ?: 1 << nkmp->m.width;
_nkmp.max_p = nkmp->p.max ?: 1 << ((1 << nkmp->p.width) - 1);
ccu_nkmp_find_best(parent_rate, rate, &_nkmp);
spin_lock_irqsave(nkmp->common.lock, flags);
reg = readl(nkmp->common.base + nkmp->common.reg);
reg &= ~GENMASK(nkmp->n.width + nkmp->n.shift - 1, nkmp->n.shift);
reg &= ~GENMASK(nkmp->k.width + nkmp->k.shift - 1, nkmp->k.shift);
reg &= ~GENMASK(nkmp->m.width + nkmp->m.shift - 1, nkmp->m.shift);
reg &= ~GENMASK(nkmp->p.width + nkmp->p.shift - 1, nkmp->p.shift);
reg |= (_nkmp.n - 1) << nkmp->n.shift;
reg |= (_nkmp.k - 1) << nkmp->k.shift;
reg |= (_nkmp.m - 1) << nkmp->m.shift;
reg |= ilog2(_nkmp.p) << nkmp->p.shift;
writel(reg, nkmp->common.base + nkmp->common.reg);
spin_unlock_irqrestore(nkmp->common.lock, flags);
ccu_helper_wait_for_lock(&nkmp->common, nkmp->lock);
return 0;
}
const struct clk_ops ccu_nkmp_ops = {
.disable = ccu_nkmp_disable,
.enable = ccu_nkmp_enable,
.is_enabled = ccu_nkmp_is_enabled,
.recalc_rate = ccu_nkmp_recalc_rate,
.round_rate = ccu_nkmp_round_rate,
.set_rate = ccu_nkmp_set_rate,
};