linux_dsm_epyc7002/drivers/clk/at91/clk-system.c
Boris BREZILLON 693bb3d99d clk: at91: propagate rate change on system clks
System clks are just gates, and thus do not provide any rate operations.
Authorize clk rate change to be propagated to system clk parents.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-03-19 15:21:52 -07:00

136 lines
3.1 KiB
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/of.h>
#include <linux/of_address.h>
#include <linux/io.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;
u8 id;
};
static int clk_system_enable(struct clk_hw *hw)
{
struct clk_system *sys = to_clk_system(hw);
struct at91_pmc *pmc = sys->pmc;
pmc_write(pmc, AT91_PMC_SCER, 1 << sys->id);
return 0;
}
static void clk_system_disable(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_enabled(struct clk_hw *hw)
{
struct clk_system *sys = to_clk_system(hw);
struct at91_pmc *pmc = sys->pmc;
return !!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id));
}
static const struct clk_ops system_ops = {
.enable = clk_system_enable,
.disable = clk_system_disable,
.is_enabled = clk_system_is_enabled,
};
static struct clk * __init
at91_clk_register_system(struct at91_pmc *pmc, const char *name,
const char *parent_name, u8 id)
{
struct clk_system *sys;
struct clk *clk = NULL;
struct clk_init_data init;
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;
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;
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;
parent_name = of_clk_get_parent_name(sysclknp, 0);
clk = at91_clk_register_system(pmc, name, parent_name, id);
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);
}