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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License 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.
*
* Copyright (C) 2013 ARM Limited
*/
#include <linux/amba/sp810.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_address.h>
#define to_clk_sp810_timerclken(_hw) \
container_of(_hw, struct clk_sp810_timerclken, hw)
struct clk_sp810;
struct clk_sp810_timerclken {
struct clk_hw hw;
struct clk *clk;
struct clk_sp810 *sp810;
int channel;
};
struct clk_sp810 {
struct device_node *node;
int refclk_index, timclk_index;
void __iomem *base;
spinlock_t lock;
struct clk_sp810_timerclken timerclken[4];
struct clk *refclk;
struct clk *timclk;
};
static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
u32 val = readl(timerclken->sp810->base + SCCTRL);
return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
}
static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
struct clk_sp810 *sp810 = timerclken->sp810;
u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
unsigned long flags = 0;
if (WARN_ON(index > 1))
return -EINVAL;
spin_lock_irqsave(&sp810->lock, flags);
val = readl(sp810->base + SCCTRL);
val &= ~(1 << shift);
val |= index << shift;
writel(val, sp810->base + SCCTRL);
spin_unlock_irqrestore(&sp810->lock, flags);
return 0;
}
/*
* FIXME - setting the parent every time .prepare is invoked is inefficient.
* This is better handled by a dedicated clock tree configuration mechanism at
* init-time. Revisit this later when such a mechanism exists
*/
static int clk_sp810_timerclken_prepare(struct clk_hw *hw)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
struct clk_sp810 *sp810 = timerclken->sp810;
struct clk *old_parent = __clk_get_parent(hw->clk);
struct clk *new_parent;
if (!sp810->refclk)
sp810->refclk = of_clk_get(sp810->node, sp810->refclk_index);
if (!sp810->timclk)
sp810->timclk = of_clk_get(sp810->node, sp810->timclk_index);
if (WARN_ON(IS_ERR(sp810->refclk) || IS_ERR(sp810->timclk)))
return -ENOENT;
/* Select fastest parent */
if (clk_get_rate(sp810->refclk) > clk_get_rate(sp810->timclk))
new_parent = sp810->refclk;
else
new_parent = sp810->timclk;
/* Switch the parent if necessary */
if (old_parent != new_parent) {
clk_prepare(new_parent);
clk_set_parent(hw->clk, new_parent);
clk_unprepare(old_parent);
}
return 0;
}
static void clk_sp810_timerclken_unprepare(struct clk_hw *hw)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
struct clk_sp810 *sp810 = timerclken->sp810;
clk_put(sp810->timclk);
clk_put(sp810->refclk);
}
static const struct clk_ops clk_sp810_timerclken_ops = {
.prepare = clk_sp810_timerclken_prepare,
.unprepare = clk_sp810_timerclken_unprepare,
.get_parent = clk_sp810_timerclken_get_parent,
.set_parent = clk_sp810_timerclken_set_parent,
};
static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
void *data)
{
struct clk_sp810 *sp810 = data;
if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
ARRAY_SIZE(sp810->timerclken)))
return NULL;
return sp810->timerclken[clkspec->args[0]].clk;
}
static void __init clk_sp810_of_setup(struct device_node *node)
{
struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
const char *parent_names[2];
char name[12];
struct clk_init_data init;
int i;
if (!sp810) {
pr_err("Failed to allocate memory for SP810!\n");
return;
}
sp810->refclk_index = of_property_match_string(node, "clock-names",
"refclk");
parent_names[0] = of_clk_get_parent_name(node, sp810->refclk_index);
sp810->timclk_index = of_property_match_string(node, "clock-names",
"timclk");
parent_names[1] = of_clk_get_parent_name(node, sp810->timclk_index);
if (!parent_names[0] || !parent_names[1]) {
pr_warn("Failed to obtain parent clocks for SP810!\n");
return;
}
sp810->node = node;
sp810->base = of_iomap(node, 0);
spin_lock_init(&sp810->lock);
init.name = name;
init.ops = &clk_sp810_timerclken_ops;
init.flags = CLK_IS_BASIC;
init.parent_names = parent_names;
init.num_parents = ARRAY_SIZE(parent_names);
for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
sp810->timerclken[i].sp810 = sp810;
sp810->timerclken[i].channel = i;
sp810->timerclken[i].hw.init = &init;
sp810->timerclken[i].clk = clk_register(NULL,
&sp810->timerclken[i].hw);
WARN_ON(IS_ERR(sp810->timerclken[i].clk));
}
of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
}
CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
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