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adbfb0056e
Introduce support for clocks that use a combination of two linear multipliers. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Michael Turquette <mturquette@baylibre.com> Link: lkml.kernel.org/r/20160629190535.11855-10-maxime.ripard@free-electrons.com
147 lines
3.4 KiB
C
147 lines
3.4 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 <linux/rational.h>
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#include "ccu_gate.h"
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#include "ccu_nk.h"
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void ccu_nk_find_best(unsigned long parent, unsigned long rate,
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unsigned int max_n, unsigned int max_k,
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unsigned int *n, unsigned int *k)
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{
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unsigned long best_rate = 0;
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unsigned int best_k = 0, best_n = 0;
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unsigned int _k, _n;
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for (_k = 1; _k <= max_k; _k++) {
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for (_n = 1; _n <= max_n; _n++) {
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unsigned long tmp_rate = parent * _n * _k;
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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_k = _k;
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best_n = _n;
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}
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}
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}
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*k = best_k;
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*n = best_n;
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}
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static void ccu_nk_disable(struct clk_hw *hw)
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{
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struct ccu_nk *nk = hw_to_ccu_nk(hw);
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return ccu_gate_helper_disable(&nk->common, nk->enable);
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}
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static int ccu_nk_enable(struct clk_hw *hw)
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{
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struct ccu_nk *nk = hw_to_ccu_nk(hw);
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return ccu_gate_helper_enable(&nk->common, nk->enable);
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}
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static int ccu_nk_is_enabled(struct clk_hw *hw)
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{
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struct ccu_nk *nk = hw_to_ccu_nk(hw);
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return ccu_gate_helper_is_enabled(&nk->common, nk->enable);
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}
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static unsigned long ccu_nk_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct ccu_nk *nk = hw_to_ccu_nk(hw);
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unsigned long rate, n, k;
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u32 reg;
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reg = readl(nk->common.base + nk->common.reg);
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n = reg >> nk->n.shift;
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n &= (1 << nk->n.width) - 1;
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k = reg >> nk->k.shift;
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k &= (1 << nk->k.width) - 1;
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rate = parent_rate * (n + 1) * (k + 1);
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if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
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rate /= nk->fixed_post_div;
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return rate;
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}
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static long ccu_nk_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_nk *nk = hw_to_ccu_nk(hw);
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unsigned int n, k;
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if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
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rate *= nk->fixed_post_div;
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ccu_nk_find_best(*parent_rate, rate,
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1 << nk->n.width, 1 << nk->k.width,
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&n, &k);
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rate = *parent_rate * n * k;
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if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
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rate = rate / nk->fixed_post_div;
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return rate;
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}
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static int ccu_nk_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_nk *nk = hw_to_ccu_nk(hw);
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unsigned long flags;
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unsigned int n, k;
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u32 reg;
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if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
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rate = rate * nk->fixed_post_div;
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ccu_nk_find_best(parent_rate, rate,
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1 << nk->n.width, 1 << nk->k.width,
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&n, &k);
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spin_lock_irqsave(nk->common.lock, flags);
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reg = readl(nk->common.base + nk->common.reg);
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reg &= ~GENMASK(nk->n.width + nk->n.shift - 1, nk->n.shift);
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reg &= ~GENMASK(nk->k.width + nk->k.shift - 1, nk->k.shift);
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writel(reg | ((k - 1) << nk->k.shift) | ((n - 1) << nk->n.shift),
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nk->common.base + nk->common.reg);
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spin_unlock_irqrestore(nk->common.lock, flags);
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ccu_helper_wait_for_lock(&nk->common, nk->lock);
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return 0;
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}
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const struct clk_ops ccu_nk_ops = {
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.disable = ccu_nk_disable,
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.enable = ccu_nk_enable,
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.is_enabled = ccu_nk_is_enabled,
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.recalc_rate = ccu_nk_recalc_rate,
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.round_rate = ccu_nk_round_rate,
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.set_rate = ccu_nk_set_rate,
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};
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