291 lines
7.1 KiB
C
291 lines
7.1 KiB
C
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/*
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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.h>
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#include <linux/clk-provider.h>
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#include <linux/delay.h>
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#include "ccu_gate.h"
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#include "ccu_mux.h"
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static u16 ccu_mux_get_prediv(struct ccu_common *common,
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struct ccu_mux_internal *cm,
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int parent_index)
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{
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u16 prediv = 1;
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u32 reg;
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if (!((common->features & CCU_FEATURE_FIXED_PREDIV) ||
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(common->features & CCU_FEATURE_VARIABLE_PREDIV) ||
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(common->features & CCU_FEATURE_ALL_PREDIV)))
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return 1;
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if (common->features & CCU_FEATURE_ALL_PREDIV)
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return common->prediv;
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reg = readl(common->base + common->reg);
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if (parent_index < 0) {
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parent_index = reg >> cm->shift;
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parent_index &= (1 << cm->width) - 1;
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}
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if (common->features & CCU_FEATURE_FIXED_PREDIV) {
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int i;
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for (i = 0; i < cm->n_predivs; i++)
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if (parent_index == cm->fixed_predivs[i].index)
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prediv = cm->fixed_predivs[i].div;
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}
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if (common->features & CCU_FEATURE_VARIABLE_PREDIV) {
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int i;
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for (i = 0; i < cm->n_var_predivs; i++)
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if (parent_index == cm->var_predivs[i].index) {
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u8 div;
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div = reg >> cm->var_predivs[i].shift;
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div &= (1 << cm->var_predivs[i].width) - 1;
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prediv = div + 1;
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}
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}
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return prediv;
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}
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unsigned long ccu_mux_helper_apply_prediv(struct ccu_common *common,
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struct ccu_mux_internal *cm,
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int parent_index,
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unsigned long parent_rate)
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{
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return parent_rate / ccu_mux_get_prediv(common, cm, parent_index);
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}
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static unsigned long ccu_mux_helper_unapply_prediv(struct ccu_common *common,
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struct ccu_mux_internal *cm,
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int parent_index,
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unsigned long parent_rate)
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{
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return parent_rate * ccu_mux_get_prediv(common, cm, parent_index);
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}
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int ccu_mux_helper_determine_rate(struct ccu_common *common,
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struct ccu_mux_internal *cm,
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struct clk_rate_request *req,
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unsigned long (*round)(struct ccu_mux_internal *,
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struct clk_hw *,
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unsigned long *,
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unsigned long,
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void *),
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void *data)
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{
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unsigned long best_parent_rate = 0, best_rate = 0;
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struct clk_hw *best_parent, *hw = &common->hw;
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unsigned int i;
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if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
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unsigned long adj_parent_rate;
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best_parent = clk_hw_get_parent(hw);
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best_parent_rate = clk_hw_get_rate(best_parent);
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adj_parent_rate = ccu_mux_helper_apply_prediv(common, cm, -1,
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best_parent_rate);
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best_rate = round(cm, best_parent, &adj_parent_rate,
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req->rate, data);
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/*
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* adj_parent_rate might have been modified by our clock.
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* Unapply the pre-divider if there's one, and give
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* the actual frequency the parent needs to run at.
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*/
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best_parent_rate = ccu_mux_helper_unapply_prediv(common, cm, -1,
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adj_parent_rate);
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goto out;
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}
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for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
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unsigned long tmp_rate, parent_rate;
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struct clk_hw *parent;
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parent = clk_hw_get_parent_by_index(hw, i);
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if (!parent)
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continue;
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parent_rate = ccu_mux_helper_apply_prediv(common, cm, i,
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clk_hw_get_rate(parent));
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tmp_rate = round(cm, parent, &parent_rate, req->rate, data);
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/*
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* parent_rate might have been modified by our clock.
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* Unapply the pre-divider if there's one, and give
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* the actual frequency the parent needs to run at.
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*/
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parent_rate = ccu_mux_helper_unapply_prediv(common, cm, i,
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parent_rate);
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if (tmp_rate == req->rate) {
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best_parent = parent;
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best_parent_rate = parent_rate;
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best_rate = tmp_rate;
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goto out;
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}
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if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
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best_rate = tmp_rate;
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best_parent_rate = parent_rate;
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best_parent = parent;
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}
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}
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if (best_rate == 0)
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return -EINVAL;
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out:
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req->best_parent_hw = best_parent;
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req->best_parent_rate = best_parent_rate;
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req->rate = best_rate;
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return 0;
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}
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u8 ccu_mux_helper_get_parent(struct ccu_common *common,
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struct ccu_mux_internal *cm)
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{
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u32 reg;
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u8 parent;
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reg = readl(common->base + common->reg);
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parent = reg >> cm->shift;
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parent &= (1 << cm->width) - 1;
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if (cm->table) {
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int num_parents = clk_hw_get_num_parents(&common->hw);
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int i;
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for (i = 0; i < num_parents; i++)
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if (cm->table[i] == parent)
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return i;
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}
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return parent;
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}
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int ccu_mux_helper_set_parent(struct ccu_common *common,
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struct ccu_mux_internal *cm,
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u8 index)
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{
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unsigned long flags;
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u32 reg;
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if (cm->table)
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index = cm->table[index];
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spin_lock_irqsave(common->lock, flags);
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reg = readl(common->base + common->reg);
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reg &= ~GENMASK(cm->width + cm->shift - 1, cm->shift);
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writel(reg | (index << cm->shift), common->base + common->reg);
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spin_unlock_irqrestore(common->lock, flags);
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return 0;
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}
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static void ccu_mux_disable(struct clk_hw *hw)
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{
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struct ccu_mux *cm = hw_to_ccu_mux(hw);
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return ccu_gate_helper_disable(&cm->common, cm->enable);
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}
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static int ccu_mux_enable(struct clk_hw *hw)
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{
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struct ccu_mux *cm = hw_to_ccu_mux(hw);
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return ccu_gate_helper_enable(&cm->common, cm->enable);
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}
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static int ccu_mux_is_enabled(struct clk_hw *hw)
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{
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struct ccu_mux *cm = hw_to_ccu_mux(hw);
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return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
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}
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static u8 ccu_mux_get_parent(struct clk_hw *hw)
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{
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struct ccu_mux *cm = hw_to_ccu_mux(hw);
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return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
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}
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static int ccu_mux_set_parent(struct clk_hw *hw, u8 index)
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{
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struct ccu_mux *cm = hw_to_ccu_mux(hw);
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return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
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}
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static unsigned long ccu_mux_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct ccu_mux *cm = hw_to_ccu_mux(hw);
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return ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
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parent_rate);
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}
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const struct clk_ops ccu_mux_ops = {
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.disable = ccu_mux_disable,
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.enable = ccu_mux_enable,
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.is_enabled = ccu_mux_is_enabled,
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.get_parent = ccu_mux_get_parent,
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.set_parent = ccu_mux_set_parent,
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.determine_rate = __clk_mux_determine_rate,
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.recalc_rate = ccu_mux_recalc_rate,
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};
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/*
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* This clock notifier is called when the frequency of the of the parent
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* PLL clock is to be changed. The idea is to switch the parent to a
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* stable clock, such as the main oscillator, while the PLL frequency
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* stabilizes.
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*/
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static int ccu_mux_notifier_cb(struct notifier_block *nb,
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unsigned long event, void *data)
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{
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struct ccu_mux_nb *mux = to_ccu_mux_nb(nb);
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int ret = 0;
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if (event == PRE_RATE_CHANGE) {
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mux->original_index = ccu_mux_helper_get_parent(mux->common,
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mux->cm);
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ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
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mux->bypass_index);
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} else if (event == POST_RATE_CHANGE) {
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ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
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mux->original_index);
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}
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udelay(mux->delay_us);
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return notifier_from_errno(ret);
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}
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int ccu_mux_notifier_register(struct clk *clk, struct ccu_mux_nb *mux_nb)
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{
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mux_nb->clk_nb.notifier_call = ccu_mux_notifier_cb;
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return clk_notifier_register(clk, &mux_nb->clk_nb);
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}
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