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/*
* 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/of.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include "pmc.h"
#define SYSTEM_MAX_ID 31
#define SYSTEM_MAX_NAME_SZ 32
#define to_clk_system(hw) container_of(hw, struct clk_system, hw)
struct clk_system {
struct clk_hw hw;
struct at91_pmc *pmc;
unsigned int irq;
wait_queue_head_t wait;
u8 id;
};
static inline int is_pck(int id)
{
return (id >= 8) && (id <= 15);
}
static irqreturn_t clk_system_irq_handler(int irq, void *dev_id)
{
struct clk_system *sys = (struct clk_system *)dev_id;
wake_up(&sys->wait);
disable_irq_nosync(sys->irq);
return IRQ_HANDLED;
}
static int clk_system_prepare(struct clk_hw *hw)
{
struct clk_system *sys = to_clk_system(hw);
struct at91_pmc *pmc = sys->pmc;
u32 mask = 1 << sys->id;
pmc_write(pmc, AT91_PMC_SCER, mask);
if (!is_pck(sys->id))
return 0;
while (!(pmc_read(pmc, AT91_PMC_SR) & mask)) {
if (sys->irq) {
enable_irq(sys->irq);
wait_event(sys->wait,
pmc_read(pmc, AT91_PMC_SR) & mask);
} else
cpu_relax();
}
return 0;
}
static void clk_system_unprepare(struct clk_hw *hw)
{
struct clk_system *sys = to_clk_system(hw);
struct at91_pmc *pmc = sys->pmc;
pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id);
}
static int clk_system_is_prepared(struct clk_hw *hw)
{
struct clk_system *sys = to_clk_system(hw);
struct at91_pmc *pmc = sys->pmc;
if (!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id)))
return 0;
if (!is_pck(sys->id))
return 1;
return !!(pmc_read(pmc, AT91_PMC_SR) & (1 << sys->id));
}
static const struct clk_ops system_ops = {
.prepare = clk_system_prepare,
.unprepare = clk_system_unprepare,
.is_prepared = clk_system_is_prepared,
};
static struct clk * __init
at91_clk_register_system(struct at91_pmc *pmc, const char *name,
const char *parent_name, u8 id, int irq)
{
struct clk_system *sys;
struct clk *clk = NULL;
struct clk_init_data init;
int ret;
if (!parent_name || id > SYSTEM_MAX_ID)
return ERR_PTR(-EINVAL);
sys = kzalloc(sizeof(*sys), GFP_KERNEL);
if (!sys)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &system_ops;
init.parent_names = &parent_name;
init.num_parents = 1;
/*
* CLK_IGNORE_UNUSED is used to avoid ddrck switch off.
* TODO : we should implement a driver supporting at91 ddr controller
* (see drivers/memory) which would request and enable the ddrck clock.
* When this is done we will be able to remove CLK_IGNORE_UNUSED flag.
*/
init.flags = CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED;
sys->id = id;
sys->hw.init = &init;
sys->pmc = pmc;
sys->irq = irq;
if (irq) {
init_waitqueue_head(&sys->wait);
irq_set_status_flags(sys->irq, IRQ_NOAUTOEN);
ret = request_irq(sys->irq, clk_system_irq_handler,
IRQF_TRIGGER_HIGH, name, sys);
if (ret)
return ERR_PTR(ret);
}
clk = clk_register(NULL, &sys->hw);
if (IS_ERR(clk))
kfree(sys);
return clk;
}
static void __init
of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc)
{
int num;
int irq = 0;
u32 id;
struct clk *clk;
const char *name;
struct device_node *sysclknp;
const char *parent_name;
num = of_get_child_count(np);
if (num > (SYSTEM_MAX_ID + 1))
return;
for_each_child_of_node(np, sysclknp) {
if (of_property_read_u32(sysclknp, "reg", &id))
continue;
if (of_property_read_string(np, "clock-output-names", &name))
name = sysclknp->name;
if (is_pck(id))
irq = irq_of_parse_and_map(sysclknp, 0);
parent_name = of_clk_get_parent_name(sysclknp, 0);
clk = at91_clk_register_system(pmc, name, parent_name, id, irq);
if (IS_ERR(clk))
continue;
of_clk_add_provider(sysclknp, of_clk_src_simple_get, clk);
}
}
void __init of_at91rm9200_clk_sys_setup(struct device_node *np,
struct at91_pmc *pmc)
{
of_at91_clk_sys_setup(np, pmc);
}
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