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![Maxime Ripard](/assets/img/avatar_default.png)
Some multipliers have a maximum rate that is lower than what the register width allows to. Add a field in the multiplier structure to allow CCU driver to set that maximum. Acked-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
157 lines
3.6 KiB
C
157 lines
3.6 KiB
C
/*
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* Copyright (C) 2016 Maxime Ripard
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*/
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#include <linux/clk-provider.h>
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#include "ccu_frac.h"
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#include "ccu_gate.h"
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#include "ccu_nm.h"
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struct _ccu_nm {
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unsigned long n, min_n, max_n;
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unsigned long m, min_m, max_m;
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};
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static void ccu_nm_find_best(unsigned long parent, unsigned long rate,
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struct _ccu_nm *nm)
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{
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unsigned long best_rate = 0;
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unsigned long best_n = 0, best_m = 0;
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unsigned long _n, _m;
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for (_n = nm->min_n; _n <= nm->max_n; _n++) {
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for (_m = nm->min_m; _m <= nm->max_m; _m++) {
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unsigned long tmp_rate = parent * _n / _m;
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if (tmp_rate > rate)
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continue;
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if ((rate - tmp_rate) < (rate - best_rate)) {
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best_rate = tmp_rate;
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best_n = _n;
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best_m = _m;
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}
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}
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}
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nm->n = best_n;
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nm->m = best_m;
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}
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static void ccu_nm_disable(struct clk_hw *hw)
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{
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struct ccu_nm *nm = hw_to_ccu_nm(hw);
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return ccu_gate_helper_disable(&nm->common, nm->enable);
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}
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static int ccu_nm_enable(struct clk_hw *hw)
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{
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struct ccu_nm *nm = hw_to_ccu_nm(hw);
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return ccu_gate_helper_enable(&nm->common, nm->enable);
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}
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static int ccu_nm_is_enabled(struct clk_hw *hw)
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{
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struct ccu_nm *nm = hw_to_ccu_nm(hw);
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return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
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}
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static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct ccu_nm *nm = hw_to_ccu_nm(hw);
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unsigned long n, m;
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u32 reg;
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if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac))
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return ccu_frac_helper_read_rate(&nm->common, &nm->frac);
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reg = readl(nm->common.base + nm->common.reg);
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n = reg >> nm->n.shift;
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n &= (1 << nm->n.width) - 1;
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n += nm->n.offset;
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if (!n)
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n++;
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m = reg >> nm->m.shift;
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m &= (1 << nm->m.width) - 1;
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m += nm->m.offset;
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if (!m)
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m++;
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return parent_rate * n / m;
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}
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static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *parent_rate)
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{
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struct ccu_nm *nm = hw_to_ccu_nm(hw);
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struct _ccu_nm _nm;
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_nm.min_n = nm->n.min;
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_nm.max_n = nm->n.max ?: 1 << nm->n.width;
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_nm.min_m = 1;
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_nm.max_m = nm->m.max ?: 1 << nm->m.width;
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ccu_nm_find_best(*parent_rate, rate, &_nm);
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return *parent_rate * _nm.n / _nm.m;
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}
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static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long parent_rate)
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{
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struct ccu_nm *nm = hw_to_ccu_nm(hw);
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struct _ccu_nm _nm;
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unsigned long flags;
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u32 reg;
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if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate))
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return ccu_frac_helper_set_rate(&nm->common, &nm->frac, rate);
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else
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ccu_frac_helper_disable(&nm->common, &nm->frac);
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_nm.min_n = 1;
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_nm.max_n = nm->n.max ?: 1 << nm->n.width;
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_nm.min_m = 1;
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_nm.max_m = nm->m.max ?: 1 << nm->m.width;
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ccu_nm_find_best(parent_rate, rate, &_nm);
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spin_lock_irqsave(nm->common.lock, flags);
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reg = readl(nm->common.base + nm->common.reg);
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reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
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reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
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reg |= (_nm.n - nm->n.offset) << nm->n.shift;
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reg |= (_nm.m - nm->m.offset) << nm->m.shift;
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writel(reg, nm->common.base + nm->common.reg);
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spin_unlock_irqrestore(nm->common.lock, flags);
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ccu_helper_wait_for_lock(&nm->common, nm->lock);
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return 0;
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}
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const struct clk_ops ccu_nm_ops = {
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.disable = ccu_nm_disable,
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.enable = ccu_nm_enable,
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.is_enabled = ccu_nm_is_enabled,
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.recalc_rate = ccu_nm_recalc_rate,
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.round_rate = ccu_nm_round_rate,
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.set_rate = ccu_nm_set_rate,
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};
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