linux/drivers/clk/sunxi-ng/ccu_nm.c
Frank Oltmanns c0380d1474 clk: sunxi-ng: nm: Support finding closest rate
Use the helper function ccu_is_better_rate() to determine the rate that
is closest to the requested rate, thereby supporting rates that are
higher than the requested rate if the clock uses the
CCU_FEATURE_CLOSEST_RATE.

Add the macro SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST which
sets CCU_FEATURE_CLOSEST_RATE.

To avoid code duplication, add the macros
SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT that allows selecting
arbitrary features and use it in the original
SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX as well as the newly introduced
SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST macros.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
Link: https://lore.kernel.org/r/20230807-pll-mipi_set_rate_parent-v6-6-f173239a4b59@oltmanns.dev
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
2023-08-09 23:33:58 +08:00

240 lines
5.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2016 Maxime Ripard
* Maxime Ripard <maxime.ripard@free-electrons.com>
*/
#include <linux/clk-provider.h>
#include <linux/io.h>
#include "ccu_frac.h"
#include "ccu_gate.h"
#include "ccu_nm.h"
struct _ccu_nm {
unsigned long n, min_n, max_n;
unsigned long m, min_m, max_m;
};
static unsigned long ccu_nm_calc_rate(unsigned long parent,
unsigned long n, unsigned long m)
{
u64 rate = parent;
rate *= n;
do_div(rate, m);
return rate;
}
static unsigned long ccu_nm_find_best(struct ccu_common *common, unsigned long parent,
unsigned long rate, struct _ccu_nm *nm)
{
unsigned long best_rate = 0;
unsigned long best_n = 0, best_m = 0;
unsigned long _n, _m;
for (_n = nm->min_n; _n <= nm->max_n; _n++) {
for (_m = nm->min_m; _m <= nm->max_m; _m++) {
unsigned long tmp_rate = ccu_nm_calc_rate(parent,
_n, _m);
if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
best_rate = tmp_rate;
best_n = _n;
best_m = _m;
}
}
}
nm->n = best_n;
nm->m = best_m;
return best_rate;
}
static void ccu_nm_disable(struct clk_hw *hw)
{
struct ccu_nm *nm = hw_to_ccu_nm(hw);
return ccu_gate_helper_disable(&nm->common, nm->enable);
}
static int ccu_nm_enable(struct clk_hw *hw)
{
struct ccu_nm *nm = hw_to_ccu_nm(hw);
return ccu_gate_helper_enable(&nm->common, nm->enable);
}
static int ccu_nm_is_enabled(struct clk_hw *hw)
{
struct ccu_nm *nm = hw_to_ccu_nm(hw);
return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
}
static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct ccu_nm *nm = hw_to_ccu_nm(hw);
unsigned long rate;
unsigned long n, m;
u32 reg;
if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) {
rate = ccu_frac_helper_read_rate(&nm->common, &nm->frac);
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
return rate;
}
reg = readl(nm->common.base + nm->common.reg);
n = reg >> nm->n.shift;
n &= (1 << nm->n.width) - 1;
n += nm->n.offset;
if (!n)
n++;
m = reg >> nm->m.shift;
m &= (1 << nm->m.width) - 1;
m += nm->m.offset;
if (!m)
m++;
if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm))
rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n);
else
rate = ccu_nm_calc_rate(parent_rate, n, m);
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
return rate;
}
static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct ccu_nm *nm = hw_to_ccu_nm(hw);
struct _ccu_nm _nm;
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate *= nm->fixed_post_div;
if (rate < nm->min_rate) {
rate = nm->min_rate;
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
return rate;
}
if (nm->max_rate && rate > nm->max_rate) {
rate = nm->max_rate;
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
return rate;
}
if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
return rate;
}
if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
return rate;
}
_nm.min_n = nm->n.min ?: 1;
_nm.max_n = nm->n.max ?: 1 << nm->n.width;
_nm.min_m = 1;
_nm.max_m = nm->m.max ?: 1 << nm->m.width;
rate = ccu_nm_find_best(&nm->common, *parent_rate, rate, &_nm);
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
return rate;
}
static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct ccu_nm *nm = hw_to_ccu_nm(hw);
struct _ccu_nm _nm;
unsigned long flags;
u32 reg;
/* Adjust target rate according to post-dividers */
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate = rate * nm->fixed_post_div;
if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
spin_lock_irqsave(nm->common.lock, flags);
/* most SoCs require M to be 0 if fractional mode is used */
reg = readl(nm->common.base + nm->common.reg);
reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
writel(reg, nm->common.base + nm->common.reg);
spin_unlock_irqrestore(nm->common.lock, flags);
ccu_frac_helper_enable(&nm->common, &nm->frac);
return ccu_frac_helper_set_rate(&nm->common, &nm->frac,
rate, nm->lock);
} else {
ccu_frac_helper_disable(&nm->common, &nm->frac);
}
_nm.min_n = nm->n.min ?: 1;
_nm.max_n = nm->n.max ?: 1 << nm->n.width;
_nm.min_m = 1;
_nm.max_m = nm->m.max ?: 1 << nm->m.width;
if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
ccu_sdm_helper_enable(&nm->common, &nm->sdm, rate);
/* Sigma delta modulation requires specific N and M factors */
ccu_sdm_helper_get_factors(&nm->common, &nm->sdm, rate,
&_nm.m, &_nm.n);
} else {
ccu_sdm_helper_disable(&nm->common, &nm->sdm);
ccu_nm_find_best(&nm->common, parent_rate, rate, &_nm);
}
spin_lock_irqsave(nm->common.lock, flags);
reg = readl(nm->common.base + nm->common.reg);
reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
reg |= (_nm.n - nm->n.offset) << nm->n.shift;
reg |= (_nm.m - nm->m.offset) << nm->m.shift;
writel(reg, nm->common.base + nm->common.reg);
spin_unlock_irqrestore(nm->common.lock, flags);
ccu_helper_wait_for_lock(&nm->common, nm->lock);
return 0;
}
const struct clk_ops ccu_nm_ops = {
.disable = ccu_nm_disable,
.enable = ccu_nm_enable,
.is_enabled = ccu_nm_is_enabled,
.recalc_rate = ccu_nm_recalc_rate,
.round_rate = ccu_nm_round_rate,
.set_rate = ccu_nm_set_rate,
};
EXPORT_SYMBOL_NS_GPL(ccu_nm_ops, SUNXI_CCU);