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linux-next/drivers/clk/sunxi-ng/ccu_mult.c
Jernej Škrabec 1d42460a49 clk: sunxi-ng: Wait for lock when using fractional mode
Currently ccu_frac_helper_set_rate() doesn't wait for a lock bit to be
set before returning. Because of that, unstable clock may be used.

Add a wait for lock in the helper function.

Fixes: 89a3dfb787 ("clk: sunxi-ng: Add fractional lib")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
2017-08-01 10:18:23 +08:00

176 lines
4.1 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 "ccu_gate.h"
#include "ccu_mult.h"
struct _ccu_mult {
unsigned long mult, min, max;
};
static void ccu_mult_find_best(unsigned long parent, unsigned long rate,
struct _ccu_mult *mult)
{
int _mult;
_mult = rate / parent;
if (_mult < mult->min)
_mult = mult->min;
if (_mult > mult->max)
_mult = mult->max;
mult->mult = _mult;
}
static unsigned long ccu_mult_round_rate(struct ccu_mux_internal *mux,
struct clk_hw *parent,
unsigned long *parent_rate,
unsigned long rate,
void *data)
{
struct ccu_mult *cm = data;
struct _ccu_mult _cm;
_cm.min = cm->mult.min;
if (cm->mult.max)
_cm.max = cm->mult.max;
else
_cm.max = (1 << cm->mult.width) + cm->mult.offset - 1;
ccu_mult_find_best(*parent_rate, rate, &_cm);
return *parent_rate * _cm.mult;
}
static void ccu_mult_disable(struct clk_hw *hw)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
return ccu_gate_helper_disable(&cm->common, cm->enable);
}
static int ccu_mult_enable(struct clk_hw *hw)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
return ccu_gate_helper_enable(&cm->common, cm->enable);
}
static int ccu_mult_is_enabled(struct clk_hw *hw)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
}
static unsigned long ccu_mult_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
unsigned long val;
u32 reg;
if (ccu_frac_helper_is_enabled(&cm->common, &cm->frac))
return ccu_frac_helper_read_rate(&cm->common, &cm->frac);
reg = readl(cm->common.base + cm->common.reg);
val = reg >> cm->mult.shift;
val &= (1 << cm->mult.width) - 1;
parent_rate = ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
parent_rate);
return parent_rate * (val + cm->mult.offset);
}
static int ccu_mult_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
return ccu_mux_helper_determine_rate(&cm->common, &cm->mux,
req, ccu_mult_round_rate, cm);
}
static int ccu_mult_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
struct _ccu_mult _cm;
unsigned long flags;
u32 reg;
if (ccu_frac_helper_has_rate(&cm->common, &cm->frac, rate)) {
ccu_frac_helper_enable(&cm->common, &cm->frac);
return ccu_frac_helper_set_rate(&cm->common, &cm->frac,
rate, cm->lock);
} else {
ccu_frac_helper_disable(&cm->common, &cm->frac);
}
parent_rate = ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
parent_rate);
_cm.min = cm->mult.min;
if (cm->mult.max)
_cm.max = cm->mult.max;
else
_cm.max = (1 << cm->mult.width) + cm->mult.offset - 1;
ccu_mult_find_best(parent_rate, rate, &_cm);
spin_lock_irqsave(cm->common.lock, flags);
reg = readl(cm->common.base + cm->common.reg);
reg &= ~GENMASK(cm->mult.width + cm->mult.shift - 1, cm->mult.shift);
reg |= ((_cm.mult - cm->mult.offset) << cm->mult.shift);
writel(reg, cm->common.base + cm->common.reg);
spin_unlock_irqrestore(cm->common.lock, flags);
ccu_helper_wait_for_lock(&cm->common, cm->lock);
return 0;
}
static u8 ccu_mult_get_parent(struct clk_hw *hw)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
}
static int ccu_mult_set_parent(struct clk_hw *hw, u8 index)
{
struct ccu_mult *cm = hw_to_ccu_mult(hw);
return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
}
const struct clk_ops ccu_mult_ops = {
.disable = ccu_mult_disable,
.enable = ccu_mult_enable,
.is_enabled = ccu_mult_is_enabled,
.get_parent = ccu_mult_get_parent,
.set_parent = ccu_mult_set_parent,
.determine_rate = ccu_mult_determine_rate,
.recalc_rate = ccu_mult_recalc_rate,
.set_rate = ccu_mult_set_rate,
};