| /* |
| * Copyright (c) 2010-2011, Code Aurora Forum. 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. |
| */ |
| |
| #include <linux/err.h> |
| #include <linux/mutex.h> |
| #include <linux/clk.h> |
| |
| #include "clock.h" |
| #include "clock-voter.h" |
| |
| static DEFINE_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; |
| |
| mutex_lock(&voter_clk_lock); |
| |
| if (v->enabled) { |
| struct clk *parent = v->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: |
| 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); |
| |
| mutex_lock(&voter_clk_lock); |
| parent = v->parent; |
| |
| /* |
| * 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: |
| 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); |
| |
| mutex_lock(&voter_clk_lock); |
| parent = v->parent; |
| |
| /* |
| * Decrease the rate if this clock was the only one voting for |
| * the highest rate. |
| */ |
| v->enabled = false; |
| 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); |
| |
| 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) |
| { |
| struct clk_voter *v = to_clk_voter(clk); |
| return clk_round_rate(v->parent, rate); |
| } |
| |
| static struct clk *voter_clk_get_parent(struct clk *clk) |
| { |
| struct clk_voter *v = to_clk_voter(clk); |
| return v->parent; |
| } |
| |
| static bool voter_clk_is_local(struct clk *clk) |
| { |
| return true; |
| } |
| |
| static enum handoff voter_clk_handoff(struct clk *clk) |
| { |
| /* Apply default rate vote */ |
| if (clk->rate) |
| return HANDOFF_ENABLED_CLK; |
| |
| return HANDOFF_DISABLED_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, |
| .get_parent = voter_clk_get_parent, |
| .is_local = voter_clk_is_local, |
| .handoff = voter_clk_handoff, |
| }; |