- 根目录:
- drivers
- clk
- at91
- clk-slow.c
/*
* drivers/clk/at91/clk-slow.c
*
* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/at91_pmc.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include "pmc.h"
#include "sckc.h"
#define SLOW_CLOCK_FREQ 32768
#define SLOWCK_SW_CYCLES 5
#define SLOWCK_SW_TIME_USEC ((SLOWCK_SW_CYCLES * USEC_PER_SEC) / \
SLOW_CLOCK_FREQ)
#define AT91_SCKC_CR 0x00
#define AT91_SCKC_RCEN (1 << 0)
#define AT91_SCKC_OSC32EN (1 << 1)
#define AT91_SCKC_OSC32BYP (1 << 2)
#define AT91_SCKC_OSCSEL (1 << 3)
struct clk_slow_osc {
struct clk_hw hw;
void __iomem *sckcr;
unsigned long startup_usec;
};
#define to_clk_slow_osc(hw) container_of(hw, struct clk_slow_osc, hw)
struct clk_slow_rc_osc {
struct clk_hw hw;
void __iomem *sckcr;
unsigned long frequency;
unsigned long accuracy;
unsigned long startup_usec;
};
#define to_clk_slow_rc_osc(hw) container_of(hw, struct clk_slow_rc_osc, hw)
struct clk_sam9260_slow {
struct clk_hw hw;
struct at91_pmc *pmc;
};
#define to_clk_sam9260_slow(hw) container_of(hw, struct clk_sam9260_slow, hw)
struct clk_sam9x5_slow {
struct clk_hw hw;
void __iomem *sckcr;
u8 parent;
};
#define to_clk_sam9x5_slow(hw) container_of(hw, struct clk_sam9x5_slow, hw)
static struct clk *slow_clk;
static int clk_slow_osc_prepare(struct clk_hw *hw)
{
struct clk_slow_osc *osc = to_clk_slow_osc(hw);
void __iomem *sckcr = osc->sckcr;
u32 tmp = readl(sckcr);
if (tmp & AT91_SCKC_OSC32BYP)
return 0;
writel(tmp | AT91_SCKC_OSC32EN, sckcr);
usleep_range(osc->startup_usec, osc->startup_usec + 1);
return 0;
}
static void clk_slow_osc_unprepare(struct clk_hw *hw)
{
struct clk_slow_osc *osc = to_clk_slow_osc(hw);
void __iomem *sckcr = osc->sckcr;
u32 tmp = readl(sckcr);
if (tmp & AT91_SCKC_OSC32BYP)
return;
writel(tmp & ~AT91_SCKC_OSC32EN, sckcr);
}
static int clk_slow_osc_is_prepared(struct clk_hw *hw)
{
struct clk_slow_osc *osc = to_clk_slow_osc(hw);
void __iomem *sckcr = osc->sckcr;
u32 tmp = readl(sckcr);
if (tmp & AT91_SCKC_OSC32BYP)
return 1;
return !!(tmp & AT91_SCKC_OSC32EN);
}
static const struct clk_ops slow_osc_ops = {
.prepare = clk_slow_osc_prepare,
.unprepare = clk_slow_osc_unprepare,
.is_prepared = clk_slow_osc_is_prepared,
};
static struct clk * __init
at91_clk_register_slow_osc(void __iomem *sckcr,
const char *name,
const char *parent_name,
unsigned long startup,
bool bypass)
{
struct clk_slow_osc *osc;
struct clk *clk = NULL;
struct clk_init_data init;
if (!sckcr || !name || !parent_name)
return ERR_PTR(-EINVAL);
osc = kzalloc(sizeof(*osc), GFP_KERNEL);
if (!osc)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &slow_osc_ops;
init.parent_names = &parent_name;
init.num_parents = 1;
init.flags = CLK_IGNORE_UNUSED;
osc->hw.init = &init;
osc->sckcr = sckcr;
osc->startup_usec = startup;
if (bypass)
writel((readl(sckcr) & ~AT91_SCKC_OSC32EN) | AT91_SCKC_OSC32BYP,
sckcr);
clk = clk_register(NULL, &osc->hw);
if (IS_ERR(clk))
kfree(osc);
return clk;
}
void __init of_at91sam9x5_clk_slow_osc_setup(struct device_node *np,
void __iomem *sckcr)
{
struct clk *clk;
const char *parent_name;
const char *name = np->name;
u32 startup;
bool bypass;
parent_name = of_clk_get_parent_name(np, 0);
of_property_read_string(np, "clock-output-names", &name);
of_property_read_u32(np, "atmel,startup-time-usec", &startup);
bypass = of_property_read_bool(np, "atmel,osc-bypass");
clk = at91_clk_register_slow_osc(sckcr, name, parent_name, startup,
bypass);
if (IS_ERR(clk))
return;
of_clk_add_provider(np, of_clk_src_simple_get, clk);
}
static unsigned long clk_slow_rc_osc_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
return osc->frequency;
}
static unsigned long clk_slow_rc_osc_recalc_accuracy(struct clk_hw *hw,
unsigned long parent_acc)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
return osc->accuracy;
}
static int clk_slow_rc_osc_prepare(struct clk_hw *hw)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
void __iomem *sckcr = osc->sckcr;
writel(readl(sckcr) | AT91_SCKC_RCEN, sckcr);
usleep_range(osc->startup_usec, osc->startup_usec + 1);
return 0;
}
static void clk_slow_rc_osc_unprepare(struct clk_hw *hw)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
void __iomem *sckcr = osc->sckcr;
writel(readl(sckcr) & ~AT91_SCKC_RCEN, sckcr);
}
static int clk_slow_rc_osc_is_prepared(struct clk_hw *hw)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
return !!(readl(osc->sckcr) & AT91_SCKC_RCEN);
}
static const struct clk_ops slow_rc_osc_ops = {
.prepare = clk_slow_rc_osc_prepare,
.unprepare = clk_slow_rc_osc_unprepare,
.is_prepared = clk_slow_rc_osc_is_prepared,
.recalc_rate = clk_slow_rc_osc_recalc_rate,
.recalc_accuracy = clk_slow_rc_osc_recalc_accuracy,
};
static struct clk * __init
at91_clk_register_slow_rc_osc(void __iomem *sckcr,
const char *name,
unsigned long frequency,
unsigned long accuracy,
unsigned long startup)
{
struct clk_slow_rc_osc *osc;
struct clk *clk = NULL;
struct clk_init_data init;
if (!sckcr || !name)
return ERR_PTR(-EINVAL);
osc = kzalloc(sizeof(*osc), GFP_KERNEL);
if (!osc)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &slow_rc_osc_ops;
init.parent_names = NULL;
init.num_parents = 0;
init.flags = CLK_IS_ROOT | CLK_IGNORE_UNUSED;
osc->hw.init = &init;
osc->sckcr = sckcr;
osc->frequency = frequency;
osc->accuracy = accuracy;
osc->startup_usec = startup;
clk = clk_register(NULL, &osc->hw);
if (IS_ERR(clk))
kfree(osc);
return clk;
}
void __init of_at91sam9x5_clk_slow_rc_osc_setup(struct device_node *np,
void __iomem *sckcr)
{
struct clk *clk;
u32 frequency = 0;
u32 accuracy = 0;
u32 startup = 0;
const char *name = np->name;
of_property_read_string(np, "clock-output-names", &name);
of_property_read_u32(np, "clock-frequency", &frequency);
of_property_read_u32(np, "clock-accuracy", &accuracy);
of_property_read_u32(np, "atmel,startup-time-usec", &startup);
clk = at91_clk_register_slow_rc_osc(sckcr, name, frequency, accuracy,
startup);
if (IS_ERR(clk))
return;
of_clk_add_provider(np, of_clk_src_simple_get, clk);
}
static int clk_sam9x5_slow_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
void __iomem *sckcr = slowck->sckcr;
u32 tmp;
if (index > 1)
return -EINVAL;
tmp = readl(sckcr);
if ((!index && !(tmp & AT91_SCKC_OSCSEL)) ||
(index && (tmp & AT91_SCKC_OSCSEL)))
return 0;
if (index)
tmp |= AT91_SCKC_OSCSEL;
else
tmp &= ~AT91_SCKC_OSCSEL;
writel(tmp, sckcr);
usleep_range(SLOWCK_SW_TIME_USEC, SLOWCK_SW_TIME_USEC + 1);
return 0;
}
static u8 clk_sam9x5_slow_get_parent(struct clk_hw *hw)
{
struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
return !!(readl(slowck->sckcr) & AT91_SCKC_OSCSEL);
}
static const struct clk_ops sam9x5_slow_ops = {
.set_parent = clk_sam9x5_slow_set_parent,
.get_parent = clk_sam9x5_slow_get_parent,
};
static struct clk * __init
at91_clk_register_sam9x5_slow(void __iomem *sckcr,
const char *name,
const char **parent_names,
int num_parents)
{
struct clk_sam9x5_slow *slowck;
struct clk *clk = NULL;
struct clk_init_data init;
if (!sckcr || !name || !parent_names || !num_parents)
return ERR_PTR(-EINVAL);
slowck = kzalloc(sizeof(*slowck), GFP_KERNEL);
if (!slowck)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &sam9x5_slow_ops;
init.parent_names = parent_names;
init.num_parents = num_parents;
init.flags = 0;
slowck->hw.init = &init;
slowck->sckcr = sckcr;
slowck->parent = !!(readl(sckcr) & AT91_SCKC_OSCSEL);
clk = clk_register(NULL, &slowck->hw);
if (IS_ERR(clk))
kfree(slowck);
else
slow_clk = clk;
return clk;
}
void __init of_at91sam9x5_clk_slow_setup(struct device_node *np,
void __iomem *sckcr)
{
struct clk *clk;
const char *parent_names[2];
int num_parents;
const char *name = np->name;
int i;
num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
if (num_parents <= 0 || num_parents > 2)
return;
for (i = 0; i < num_parents; ++i) {
parent_names[i] = of_clk_get_parent_name(np, i);
if (!parent_names[i])
return;
}
of_property_read_string(np, "clock-output-names", &name);
clk = at91_clk_register_sam9x5_slow(sckcr, name, parent_names,
num_parents);
if (IS_ERR(clk))
return;
of_clk_add_provider(np, of_clk_src_simple_get, clk);
}
static u8 clk_sam9260_slow_get_parent(struct clk_hw *hw)
{
struct clk_sam9260_slow *slowck = to_clk_sam9260_slow(hw);
return !!(pmc_read(slowck->pmc, AT91_PMC_SR) & AT91_PMC_OSCSEL);
}
static const struct clk_ops sam9260_slow_ops = {
.get_parent = clk_sam9260_slow_get_parent,
};
static struct clk * __init
at91_clk_register_sam9260_slow(struct at91_pmc *pmc,
const char *name,
const char **parent_names,
int num_parents)
{
struct clk_sam9260_slow *slowck;
struct clk *clk = NULL;
struct clk_init_data init;
if (!pmc || !name)
return ERR_PTR(-EINVAL);
if (!parent_names || !num_parents)
return ERR_PTR(-EINVAL);
slowck = kzalloc(sizeof(*slowck), GFP_KERNEL);
if (!slowck)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &sam9260_slow_ops;
init.parent_names = parent_names;
init.num_parents = num_parents;
init.flags = 0;
slowck->hw.init = &init;
slowck->pmc = pmc;
clk = clk_register(NULL, &slowck->hw);
if (IS_ERR(clk))
kfree(slowck);
else
slow_clk = clk;
return clk;
}
void __init of_at91sam9260_clk_slow_setup(struct device_node *np,
struct at91_pmc *pmc)
{
struct clk *clk;
const char *parent_names[2];
int num_parents;
const char *name = np->name;
int i;
num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
if (num_parents != 2)
return;
for (i = 0; i < num_parents; ++i) {
parent_names[i] = of_clk_get_parent_name(np, i);
if (!parent_names[i])
return;
}
of_property_read_string(np, "clock-output-names", &name);
clk = at91_clk_register_sam9260_slow(pmc, name, parent_names,
num_parents);
if (IS_ERR(clk))
return;
of_clk_add_provider(np, of_clk_src_simple_get, clk);
}
/*
* FIXME: All slow clk users are not properly claiming it (get + prepare +
* enable) before using it.
* If all users properly claiming this clock decide that they don't need it
* anymore (or are removed), it is disabled while faulty users are still
* requiring it, and the system hangs.
* Prevent this clock from being disabled until all users are properly
* requesting it.
* Once this is done we should remove this function and the slow_clk variable.
*/
static int __init of_at91_clk_slow_retain(void)
{
if (!slow_clk)
return 0;
__clk_get(slow_clk);
clk_prepare_enable(slow_clk);
return 0;
}
arch_initcall(of_at91_clk_slow_retain);