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/* Copyright (c) 2010-2015, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/err.h>
#include <linux/rtmutex.h>
#include <linux/clk.h>
#include <linux/clk/msm-clk-provider.h>
#include <soc/qcom/clock-voter.h>
#include <soc/qcom/msm-clock-controller.h>
static DEFINE_RT_MUTEX(voter_clk_lock);
/* Aggregate the rate of clocks that are currently on. */
static unsigned long voter_clk_aggregate_rate(const struct clk *parent)
{
struct clk *clk;
unsigned long rate = 0;
list_for_each_entry(clk, &parent->children, siblings) {
struct clk_voter *v = to_clk_voter(clk);
if (v->enabled)
rate = max(clk->rate, rate);
}
return rate;
}
static int voter_clk_set_rate(struct clk *clk, unsigned long rate)
{
int ret = 0;
struct clk *clkp;
struct clk_voter *clkh, *v = to_clk_voter(clk);
unsigned long cur_rate, new_rate, other_rate = 0;
if (v->is_branch)
return 0;
rt_mutex_lock(&voter_clk_lock);
if (v->enabled) {
struct clk *parent = clk->parent;
/*
* Get the aggregate rate without this clock's vote and update
* if the new rate is different than the current rate
*/
list_for_each_entry(clkp, &parent->children, siblings) {
clkh = to_clk_voter(clkp);
if (clkh->enabled && clkh != v)
other_rate = max(clkp->rate, other_rate);
}
cur_rate = max(other_rate, clk->rate);
new_rate = max(other_rate, rate);
if (new_rate != cur_rate) {
ret = clk_set_rate(parent, new_rate);
if (ret)
goto unlock;
}
}
clk->rate = rate;
unlock:
rt_mutex_unlock(&voter_clk_lock);
return ret;
}
static int voter_clk_prepare(struct clk *clk)
{
int ret = 0;
unsigned long cur_rate;
struct clk *parent;
struct clk_voter *v = to_clk_voter(clk);
rt_mutex_lock(&voter_clk_lock);
parent = clk->parent;
if (v->is_branch) {
v->enabled = true;
goto out;
}
/*
* Increase the rate if this clock is voting for a higher rate
* than the current rate.
*/
cur_rate = voter_clk_aggregate_rate(parent);
if (clk->rate > cur_rate) {
ret = clk_set_rate(parent, clk->rate);
if (ret)
goto out;
}
v->enabled = true;
out:
rt_mutex_unlock(&voter_clk_lock);
return ret;
}
static void voter_clk_unprepare(struct clk *clk)
{
unsigned long cur_rate, new_rate;
struct clk *parent;
struct clk_voter *v = to_clk_voter(clk);
rt_mutex_lock(&voter_clk_lock);
parent = clk->parent;
/*
* Decrease the rate if this clock was the only one voting for
* the highest rate.
*/
v->enabled = false;
if (v->is_branch)
goto out;
new_rate = voter_clk_aggregate_rate(parent);
cur_rate = max(new_rate, clk->rate);
if (new_rate < cur_rate)
clk_set_rate(parent, new_rate);
out:
rt_mutex_unlock(&voter_clk_lock);
}
static int voter_clk_is_enabled(struct clk *clk)
{
struct clk_voter *v = to_clk_voter(clk);
return v->enabled;
}
static long voter_clk_round_rate(struct clk *clk, unsigned long rate)
{
return clk_round_rate(clk->parent, rate);
}
static bool voter_clk_is_local(struct clk *clk)
{
return true;
}
static enum handoff voter_clk_handoff(struct clk *clk)
{
if (!clk->rate)
return HANDOFF_DISABLED_CLK;
/*
* Send the default rate to the parent if necessary and update the
* software state of the voter clock.
*/
if (voter_clk_prepare(clk) < 0)
return HANDOFF_DISABLED_CLK;
return HANDOFF_ENABLED_CLK;
}
struct clk_ops clk_ops_voter = {
.prepare = voter_clk_prepare,
.unprepare = voter_clk_unprepare,
.set_rate = voter_clk_set_rate,
.is_enabled = voter_clk_is_enabled,
.round_rate = voter_clk_round_rate,
.is_local = voter_clk_is_local,
.handoff = voter_clk_handoff,
};
static void *sw_vote_clk_dt_parser(struct device *dev,
struct device_node *np)
{
struct clk_voter *v;
int rc;
u32 temp;
v = devm_kzalloc(dev, sizeof(*v), GFP_KERNEL);
if (!v) {
dt_err(np, "failed to alloc memory\n");
return ERR_PTR(-ENOMEM);
}
rc = of_property_read_u32(np, "qcom,config-rate", &temp);
if (rc) {
dt_prop_err(np, "qcom,config-rate", "is missing");
return ERR_PTR(rc);
}
v->c.ops = &clk_ops_voter;
return msmclk_generic_clk_init(dev, np, &v->c);
}
MSMCLK_PARSER(sw_vote_clk_dt_parser, "qcom,sw-vote-clk", 0);
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