146 lines
3.4 KiB
C
146 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
|
|
*/
|
|
|
|
#include <linux/clk-provider.h>
|
|
#include <linux/err.h>
|
|
#include <linux/io.h>
|
|
#include <linux/mfd/syscon.h>
|
|
#include <linux/of.h>
|
|
#include <linux/of_address.h>
|
|
#include <linux/regmap.h>
|
|
#include <linux/slab.h>
|
|
|
|
#define PMU_XTAL_FREQ_RATIO 0x66c
|
|
#define XTAL_ALP_PER_4ILP 0x00001fff
|
|
#define XTAL_CTL_EN 0x80000000
|
|
#define PMU_SLOW_CLK_PERIOD 0x6dc
|
|
|
|
struct bcm53573_ilp {
|
|
struct clk_hw hw;
|
|
struct regmap *regmap;
|
|
};
|
|
|
|
static int bcm53573_ilp_enable(struct clk_hw *hw)
|
|
{
|
|
struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
|
|
|
|
regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0x10199);
|
|
regmap_write(ilp->regmap, 0x674, 0x10000);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void bcm53573_ilp_disable(struct clk_hw *hw)
|
|
{
|
|
struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
|
|
|
|
regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0);
|
|
regmap_write(ilp->regmap, 0x674, 0);
|
|
}
|
|
|
|
static unsigned long bcm53573_ilp_recalc_rate(struct clk_hw *hw,
|
|
unsigned long parent_rate)
|
|
{
|
|
struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
|
|
struct regmap *regmap = ilp->regmap;
|
|
u32 last_val, cur_val;
|
|
int sum = 0, num = 0, loop_num = 0;
|
|
int avg;
|
|
|
|
/* Enable measurement */
|
|
regmap_write(regmap, PMU_XTAL_FREQ_RATIO, XTAL_CTL_EN);
|
|
|
|
/* Read initial value */
|
|
regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &last_val);
|
|
last_val &= XTAL_ALP_PER_4ILP;
|
|
|
|
/*
|
|
* At minimum we should loop for a bit to let hardware do the
|
|
* measurement. This isn't very accurate however, so for a better
|
|
* precision lets try getting 20 different values for and use average.
|
|
*/
|
|
while (num < 20) {
|
|
regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &cur_val);
|
|
cur_val &= XTAL_ALP_PER_4ILP;
|
|
|
|
if (cur_val != last_val) {
|
|
/* Got different value, use it */
|
|
sum += cur_val;
|
|
num++;
|
|
loop_num = 0;
|
|
last_val = cur_val;
|
|
} else if (++loop_num > 5000) {
|
|
/* Same value over and over, give up */
|
|
sum += cur_val;
|
|
num++;
|
|
break;
|
|
}
|
|
|
|
cpu_relax();
|
|
}
|
|
|
|
/* Disable measurement to save power */
|
|
regmap_write(regmap, PMU_XTAL_FREQ_RATIO, 0x0);
|
|
|
|
avg = sum / num;
|
|
|
|
return parent_rate * 4 / avg;
|
|
}
|
|
|
|
static const struct clk_ops bcm53573_ilp_clk_ops = {
|
|
.enable = bcm53573_ilp_enable,
|
|
.disable = bcm53573_ilp_disable,
|
|
.recalc_rate = bcm53573_ilp_recalc_rate,
|
|
};
|
|
|
|
static void bcm53573_ilp_init(struct device_node *np)
|
|
{
|
|
struct bcm53573_ilp *ilp;
|
|
struct clk_init_data init = { };
|
|
const char *parent_name;
|
|
int err;
|
|
|
|
ilp = kzalloc(sizeof(*ilp), GFP_KERNEL);
|
|
if (!ilp)
|
|
return;
|
|
|
|
parent_name = of_clk_get_parent_name(np, 0);
|
|
if (!parent_name) {
|
|
err = -ENOENT;
|
|
goto err_free_ilp;
|
|
}
|
|
|
|
ilp->regmap = syscon_node_to_regmap(of_get_parent(np));
|
|
if (IS_ERR(ilp->regmap)) {
|
|
err = PTR_ERR(ilp->regmap);
|
|
goto err_free_ilp;
|
|
}
|
|
|
|
init.name = np->name;
|
|
init.ops = &bcm53573_ilp_clk_ops;
|
|
init.parent_names = &parent_name;
|
|
init.num_parents = 1;
|
|
|
|
ilp->hw.init = &init;
|
|
err = clk_hw_register(NULL, &ilp->hw);
|
|
if (err)
|
|
goto err_free_ilp;
|
|
|
|
err = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &ilp->hw);
|
|
if (err)
|
|
goto err_clk_hw_unregister;
|
|
|
|
return;
|
|
|
|
err_clk_hw_unregister:
|
|
clk_hw_unregister(&ilp->hw);
|
|
err_free_ilp:
|
|
kfree(ilp);
|
|
pr_err("Failed to init ILP clock: %d\n", err);
|
|
}
|
|
|
|
/* We need it very early for arch code, before device model gets ready */
|
|
CLK_OF_DECLARE(bcm53573_ilp_clk, "brcm,bcm53573-ilp", bcm53573_ilp_init);
|