// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Microchip Sparx5 SoC Clock driver.
*
* Copyright (c) 2019 Microchip Inc.
*
* Author: Lars Povlsen <[email protected]>
*/
#include <linux/io.h>
#include <linux/module.h>
#include <linux/clk-provider.h>
#include <linux/bitfield.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <dt-bindings/clock/microchip,sparx5.h>
#define PLL_DIV GENMASK(7, 0)
#define PLL_PRE_DIV GENMASK(10, 8)
#define PLL_ROT_DIR BIT(11)
#define PLL_ROT_SEL GENMASK(13, 12)
#define PLL_ROT_ENA BIT(14)
#define PLL_CLK_ENA BIT(15)
#define MAX_SEL 4
#define MAX_PRE BIT(3)
static const u8 sel_rates[MAX_SEL] = { 0, 2*8, 2*4, 2*2 };
static const char *clk_names[N_CLOCKS] = {
"core", "ddr", "cpu2", "arm2",
"aux1", "aux2", "aux3", "aux4",
"synce",
};
struct s5_hw_clk {
struct clk_hw hw;
void __iomem *reg;
};
struct s5_clk_data {
void __iomem *base;
struct s5_hw_clk s5_hw[N_CLOCKS];
};
struct s5_pll_conf {
unsigned long freq;
u8 div;
bool rot_ena;
u8 rot_sel;
u8 rot_dir;
u8 pre_div;
};
#define to_s5_pll(hw) container_of(hw, struct s5_hw_clk, hw)
static unsigned long s5_calc_freq(unsigned long parent_rate,
const struct s5_pll_conf *conf)
{
unsigned long rate = parent_rate / conf->div;
if (conf->rot_ena) {
int sign = conf->rot_dir ? -1 : 1;
int divt = sel_rates[conf->rot_sel] * (1 + conf->pre_div);
int divb = divt + sign;
rate = mult_frac(rate, divt, divb);
rate = roundup(rate, 1000);
}
return rate;
}
static void s5_search_fractional(unsigned long rate,
unsigned long parent_rate,
int div,
struct s5_pll_conf *conf)
{
struct s5_pll_conf best;
ulong cur_offset, best_offset = rate;
int d, i, j;
memset(conf, 0, sizeof(*conf));
conf->div = div;
conf->rot_ena = 1; /* Fractional rate */
for (d = 0; best_offset > 0 && d <= 1 ; d++) {
conf->rot_dir = !!d;
for (i = 0; best_offset > 0 && i < MAX_PRE; i++) {
conf->pre_div = i;
for (j = 1; best_offset > 0 && j < MAX_SEL; j++) {
conf->rot_sel = j;
conf->freq = s5_calc_freq(parent_rate, conf);
cur_offset = abs(rate - conf->freq);
if (cur_offset < best_offset) {
best_offset = cur_offset;
best = *conf;
}
}
}
}
/* Best match */
*conf = best;
}
static unsigned long s5_calc_params(unsigned long rate,
unsigned long parent_rate,
struct s5_pll_conf *conf)
{
if (parent_rate % rate) {
struct s5_pll_conf alt1, alt2;
int div;
div = DIV_ROUND_CLOSEST_ULL(parent_rate, rate);
s5_search_fractional(rate, parent_rate, div, &alt1);
/* Straight match? */
if (alt1.freq == rate) {
*conf = alt1;
} else {
/* Try without rounding divider */
div = parent_rate / rate;
if (div != alt1.div) {
s5_search_fractional(rate, parent_rate, div,
&alt2);
/* Select the better match */
if (abs(rate - alt1.freq) <
abs(rate - alt2.freq))
*conf = alt1;
else
*conf = alt2;
}
}
} else {
/* Straight fit */
memset(conf, 0, sizeof(*conf));
conf->div = parent_rate / rate;
}
return conf->freq;
}
static int s5_pll_enable(struct clk_hw *hw)
{
struct s5_hw_clk *pll = to_s5_pll(hw);
u32 val = readl(pll->reg);
val |= PLL_CLK_ENA;
writel(val, pll->reg);
return 0;
}
static void s5_pll_disable(struct clk_hw *hw)
{
struct s5_hw_clk *pll = to_s5_pll(hw);
u32 val = readl(pll->reg);
val &= ~PLL_CLK_ENA;
writel(val, pll->reg);
}
static int s5_pll_set_rate(struct clk_hw *hw,
unsigned long rate,
unsigned long parent_rate)
{
struct s5_hw_clk *pll = to_s5_pll(hw);
struct s5_pll_conf conf;
unsigned long eff_rate;
u32 val;
eff_rate = s5_calc_params(rate, parent_rate, &conf);
if (eff_rate != rate)
return -EOPNOTSUPP;
val = readl(pll->reg) & PLL_CLK_ENA;
val |= FIELD_PREP(PLL_DIV, conf.div);
if (conf.rot_ena) {
val |= PLL_ROT_ENA;
val |= FIELD_PREP(PLL_ROT_SEL, conf.rot_sel);
val |= FIELD_PREP(PLL_PRE_DIV, conf.pre_div);
if (conf.rot_dir)
val |= PLL_ROT_DIR;
}
writel(val, pll->reg);
return 0;
}
static unsigned long s5_pll_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct s5_hw_clk *pll = to_s5_pll(hw);
struct s5_pll_conf conf;
u32 val;
val = readl(pll->reg);
if (val & PLL_CLK_ENA) {
conf.div = FIELD_GET(PLL_DIV, val);
conf.pre_div = FIELD_GET(PLL_PRE_DIV, val);
conf.rot_ena = FIELD_GET(PLL_ROT_ENA, val);
conf.rot_dir = FIELD_GET(PLL_ROT_DIR, val);
conf.rot_sel = FIELD_GET(PLL_ROT_SEL, val);
conf.freq = s5_calc_freq(parent_rate, &conf);
} else {
conf.freq = 0;
}
return conf.freq;
}
static long s5_pll_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct s5_pll_conf conf;
return s5_calc_params(rate, *parent_rate, &conf);
}
static const struct clk_ops s5_pll_ops = {
.enable = s5_pll_enable,
.disable = s5_pll_disable,
.set_rate = s5_pll_set_rate,
.round_rate = s5_pll_round_rate,
.recalc_rate = s5_pll_recalc_rate,
};
static struct clk_hw *s5_clk_hw_get(struct of_phandle_args *clkspec, void *data)
{
struct s5_clk_data *s5_clk = data;
unsigned int idx = clkspec->args[0];
if (idx >= N_CLOCKS) {
pr_err("%s: invalid index %u\n", __func__, idx);
return ERR_PTR(-EINVAL);
}
return &s5_clk->s5_hw[idx].hw;
}
static int s5_clk_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
int i, ret;
struct s5_clk_data *s5_clk;
struct clk_parent_data pdata = { .index = 0 };
struct clk_init_data init = {
.ops = &s5_pll_ops,
.num_parents = 1,
.parent_data = &pdata,
};
s5_clk = devm_kzalloc(dev, sizeof(*s5_clk), GFP_KERNEL);
if (!s5_clk)
return -ENOMEM;
s5_clk->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(s5_clk->base))
return PTR_ERR(s5_clk->base);
for (i = 0; i < N_CLOCKS; i++) {
struct s5_hw_clk *s5_hw = &s5_clk->s5_hw[i];
init.name = clk_names[i];
s5_hw->reg = s5_clk->base + (i * 4);
s5_hw->hw.init = &init;
ret = devm_clk_hw_register(dev, &s5_hw->hw);
if (ret) {
dev_err(dev, "failed to register %s clock\n",
init.name);
return ret;
}
}
return devm_of_clk_add_hw_provider(dev, s5_clk_hw_get, s5_clk);
}
static const struct of_device_id s5_clk_dt_ids[] = {
{ .compatible = "microchip,sparx5-dpll", },
{ }
};
MODULE_DEVICE_TABLE(of, s5_clk_dt_ids);
static struct platform_driver s5_clk_driver = {
.probe = s5_clk_probe,
.driver = {
.name = "sparx5-clk",
.of_match_table = s5_clk_dt_ids,
},
};
builtin_platform_driver(s5_clk_driver);
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