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138 lines
4.1 KiB
138 lines
4.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (c) 2017 BayLibre, SAS |
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* Author: Neil Armstrong <[email protected]> |
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* Author: Jerome Brunet <[email protected]> |
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*/ |
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/* |
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* The AO Domain embeds a dual/divider to generate a more precise |
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* 32,768KHz clock for low-power suspend mode and CEC. |
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* ______ ______ |
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* | | | | |
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* | Div1 |-| Cnt1 | |
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* /|______| |______|\ |
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* -| ______ ______ X--> Out |
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* \| | | |/ |
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* | Div2 |-| Cnt2 | |
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* |______| |______| |
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* |
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* The dividing can be switched to single or dual, with a counter |
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* for each divider to set when the switching is done. |
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*/ |
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#include <linux/clk-provider.h> |
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#include <linux/module.h> |
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#include "clk-regmap.h" |
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#include "clk-dualdiv.h" |
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static inline struct meson_clk_dualdiv_data * |
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meson_clk_dualdiv_data(struct clk_regmap *clk) |
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{ |
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return (struct meson_clk_dualdiv_data *)clk->data; |
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} |
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static unsigned long |
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__dualdiv_param_to_rate(unsigned long parent_rate, |
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const struct meson_clk_dualdiv_param *p) |
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{ |
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if (!p->dual) |
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return DIV_ROUND_CLOSEST(parent_rate, p->n1); |
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return DIV_ROUND_CLOSEST(parent_rate * (p->m1 + p->m2), |
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p->n1 * p->m1 + p->n2 * p->m2); |
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} |
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static unsigned long meson_clk_dualdiv_recalc_rate(struct clk_hw *hw, |
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unsigned long parent_rate) |
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{ |
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struct clk_regmap *clk = to_clk_regmap(hw); |
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struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk); |
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struct meson_clk_dualdiv_param setting; |
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setting.dual = meson_parm_read(clk->map, &dualdiv->dual); |
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setting.n1 = meson_parm_read(clk->map, &dualdiv->n1) + 1; |
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setting.m1 = meson_parm_read(clk->map, &dualdiv->m1) + 1; |
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setting.n2 = meson_parm_read(clk->map, &dualdiv->n2) + 1; |
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setting.m2 = meson_parm_read(clk->map, &dualdiv->m2) + 1; |
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return __dualdiv_param_to_rate(parent_rate, &setting); |
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} |
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static const struct meson_clk_dualdiv_param * |
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__dualdiv_get_setting(unsigned long rate, unsigned long parent_rate, |
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struct meson_clk_dualdiv_data *dualdiv) |
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{ |
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const struct meson_clk_dualdiv_param *table = dualdiv->table; |
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unsigned long best = 0, now = 0; |
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unsigned int i, best_i = 0; |
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if (!table) |
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return NULL; |
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for (i = 0; table[i].n1; i++) { |
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now = __dualdiv_param_to_rate(parent_rate, &table[i]); |
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/* If we get an exact match, don't bother any further */ |
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if (now == rate) { |
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return &table[i]; |
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} else if (abs(now - rate) < abs(best - rate)) { |
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best = now; |
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best_i = i; |
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} |
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} |
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return (struct meson_clk_dualdiv_param *)&table[best_i]; |
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} |
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static long meson_clk_dualdiv_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 clk_regmap *clk = to_clk_regmap(hw); |
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struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk); |
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const struct meson_clk_dualdiv_param *setting = |
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__dualdiv_get_setting(rate, *parent_rate, dualdiv); |
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if (!setting) |
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return meson_clk_dualdiv_recalc_rate(hw, *parent_rate); |
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return __dualdiv_param_to_rate(*parent_rate, setting); |
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} |
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static int meson_clk_dualdiv_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 clk_regmap *clk = to_clk_regmap(hw); |
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struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk); |
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const struct meson_clk_dualdiv_param *setting = |
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__dualdiv_get_setting(rate, parent_rate, dualdiv); |
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if (!setting) |
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return -EINVAL; |
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meson_parm_write(clk->map, &dualdiv->dual, setting->dual); |
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meson_parm_write(clk->map, &dualdiv->n1, setting->n1 - 1); |
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meson_parm_write(clk->map, &dualdiv->m1, setting->m1 - 1); |
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meson_parm_write(clk->map, &dualdiv->n2, setting->n2 - 1); |
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meson_parm_write(clk->map, &dualdiv->m2, setting->m2 - 1); |
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return 0; |
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} |
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const struct clk_ops meson_clk_dualdiv_ops = { |
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.recalc_rate = meson_clk_dualdiv_recalc_rate, |
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.round_rate = meson_clk_dualdiv_round_rate, |
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.set_rate = meson_clk_dualdiv_set_rate, |
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}; |
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EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ops); |
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const struct clk_ops meson_clk_dualdiv_ro_ops = { |
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.recalc_rate = meson_clk_dualdiv_recalc_rate, |
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}; |
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EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ro_ops); |
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MODULE_DESCRIPTION("Amlogic dual divider driver"); |
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MODULE_AUTHOR("Neil Armstrong <[email protected]>"); |
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MODULE_AUTHOR("Jerome Brunet <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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