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/*
* H8S2678 clock driver
*
* Copyright 2015 Yoshinori Sato <ysato@users.sourceforge.jp>
*/
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/of_address.h>
static DEFINE_SPINLOCK(clklock);
#define MAX_FREQ 33333333
#define MIN_FREQ 8000000
struct pll_clock {
struct clk_hw hw;
void __iomem *sckcr;
void __iomem *pllcr;
};
#define to_pll_clock(_hw) container_of(_hw, struct pll_clock, hw)
static unsigned long pll_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct pll_clock *pll_clock = to_pll_clock(hw);
int mul = 1 << (readb(pll_clock->pllcr) & 3);
return parent_rate * mul;
}
static long pll_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
int i, m = -1;
long offset[3];
if (rate > MAX_FREQ)
rate = MAX_FREQ;
if (rate < MIN_FREQ)
rate = MIN_FREQ;
for (i = 0; i < 3; i++)
offset[i] = abs(rate - (*prate * (1 << i)));
for (i = 0; i < 3; i++)
if (m < 0)
m = i;
else
m = (offset[i] < offset[m])?i:m;
return *prate * (1 << m);
}
static int pll_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
int pll;
unsigned char val;
unsigned long flags;
struct pll_clock *pll_clock = to_pll_clock(hw);
pll = ((rate / parent_rate) / 2) & 0x03;
spin_lock_irqsave(&clklock, flags);
val = readb(pll_clock->sckcr);
val |= 0x08;
writeb(val, pll_clock->sckcr);
val = readb(pll_clock->pllcr);
val &= ~0x03;
val |= pll;
writeb(val, pll_clock->pllcr);
spin_unlock_irqrestore(&clklock, flags);
return 0;
}
static const struct clk_ops pll_ops = {
.recalc_rate = pll_recalc_rate,
.round_rate = pll_round_rate,
.set_rate = pll_set_rate,
};
static void __init h8s2678_pll_clk_setup(struct device_node *node)
{
int num_parents;
struct clk *clk;
const char *clk_name = node->name;
const char *parent_name;
struct pll_clock *pll_clock;
struct clk_init_data init;
num_parents = of_clk_get_parent_count(node);
if (num_parents < 1) {
pr_err("%s: no parent found", clk_name);
return;
}
pll_clock = kzalloc(sizeof(*pll_clock), GFP_KERNEL);
if (!pll_clock)
return;
pll_clock->sckcr = of_iomap(node, 0);
if (pll_clock->sckcr == NULL) {
pr_err("%s: failed to map divide register", clk_name);
goto free_clock;
}
pll_clock->pllcr = of_iomap(node, 1);
if (pll_clock->pllcr == NULL) {
pr_err("%s: failed to map multiply register", clk_name);
goto unmap_sckcr;
}
parent_name = of_clk_get_parent_name(node, 0);
init.name = clk_name;
init.ops = &pll_ops;
init.flags = CLK_IS_BASIC;
init.parent_names = &parent_name;
init.num_parents = 1;
pll_clock->hw.init = &init;
clk = clk_register(NULL, &pll_clock->hw);
if (IS_ERR(clk)) {
pr_err("%s: failed to register %s div clock (%ld)\n",
__func__, clk_name, PTR_ERR(clk));
goto unmap_pllcr;
}
of_clk_add_provider(node, of_clk_src_simple_get, clk);
return;
unmap_pllcr:
iounmap(pll_clock->pllcr);
unmap_sckcr:
iounmap(pll_clock->sckcr);
free_clock:
kfree(pll_clock);
}
CLK_OF_DECLARE(h8s2678_div_clk, "renesas,h8s2678-pll-clock",
h8s2678_pll_clk_setup);
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