https://github.com/torvalds/linux
Tip revision: 41bccc98fb7931d63d03f326a746ac4d429c1dd3 authored by Linus Torvalds on 29 January 2024, 01:01:12 UTC
Linux 6.8-rc2
Linux 6.8-rc2
Tip revision: 41bccc9
clk-pll.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
*/
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/at91_pmc.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include "pmc.h"
#define PLL_STATUS_MASK(id) (1 << (1 + (id)))
#define PLL_REG(id) (AT91_CKGR_PLLAR + ((id) * 4))
#define PLL_DIV_MASK 0xff
#define PLL_DIV_MAX PLL_DIV_MASK
#define PLL_DIV(reg) ((reg) & PLL_DIV_MASK)
#define PLL_MUL(reg, layout) (((reg) >> (layout)->mul_shift) & \
(layout)->mul_mask)
#define PLL_MUL_MIN 2
#define PLL_MUL_MASK(layout) ((layout)->mul_mask)
#define PLL_MUL_MAX(layout) (PLL_MUL_MASK(layout) + 1)
#define PLL_ICPR_SHIFT(id) ((id) * 16)
#define PLL_ICPR_MASK(id) (0xffff << PLL_ICPR_SHIFT(id))
#define PLL_MAX_COUNT 0x3f
#define PLL_COUNT_SHIFT 8
#define PLL_OUT_SHIFT 14
#define PLL_MAX_ID 1
#define to_clk_pll(hw) container_of(hw, struct clk_pll, hw)
struct clk_pll {
struct clk_hw hw;
struct regmap *regmap;
u8 id;
u8 div;
u8 range;
u16 mul;
const struct clk_pll_layout *layout;
const struct clk_pll_characteristics *characteristics;
struct at91_clk_pms pms;
};
static inline bool clk_pll_ready(struct regmap *regmap, int id)
{
unsigned int status;
regmap_read(regmap, AT91_PMC_SR, &status);
return status & PLL_STATUS_MASK(id) ? 1 : 0;
}
static int clk_pll_prepare(struct clk_hw *hw)
{
struct clk_pll *pll = to_clk_pll(hw);
struct regmap *regmap = pll->regmap;
const struct clk_pll_layout *layout = pll->layout;
const struct clk_pll_characteristics *characteristics =
pll->characteristics;
u8 id = pll->id;
u32 mask = PLL_STATUS_MASK(id);
int offset = PLL_REG(id);
u8 out = 0;
unsigned int pllr;
unsigned int status;
u8 div;
u16 mul;
regmap_read(regmap, offset, &pllr);
div = PLL_DIV(pllr);
mul = PLL_MUL(pllr, layout);
regmap_read(regmap, AT91_PMC_SR, &status);
if ((status & mask) &&
(div == pll->div && mul == pll->mul))
return 0;
if (characteristics->out)
out = characteristics->out[pll->range];
if (characteristics->icpll)
regmap_update_bits(regmap, AT91_PMC_PLLICPR, PLL_ICPR_MASK(id),
characteristics->icpll[pll->range] << PLL_ICPR_SHIFT(id));
regmap_update_bits(regmap, offset, layout->pllr_mask,
pll->div | (PLL_MAX_COUNT << PLL_COUNT_SHIFT) |
(out << PLL_OUT_SHIFT) |
((pll->mul & layout->mul_mask) << layout->mul_shift));
while (!clk_pll_ready(regmap, pll->id))
cpu_relax();
return 0;
}
static int clk_pll_is_prepared(struct clk_hw *hw)
{
struct clk_pll *pll = to_clk_pll(hw);
return clk_pll_ready(pll->regmap, pll->id);
}
static void clk_pll_unprepare(struct clk_hw *hw)
{
struct clk_pll *pll = to_clk_pll(hw);
unsigned int mask = pll->layout->pllr_mask;
regmap_update_bits(pll->regmap, PLL_REG(pll->id), mask, ~mask);
}
static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_pll *pll = to_clk_pll(hw);
if (!pll->div || !pll->mul)
return 0;
return (parent_rate / pll->div) * (pll->mul + 1);
}
static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
unsigned long parent_rate,
u32 *div, u32 *mul,
u32 *index) {
const struct clk_pll_layout *layout = pll->layout;
const struct clk_pll_characteristics *characteristics =
pll->characteristics;
unsigned long bestremainder = ULONG_MAX;
unsigned long maxdiv, mindiv, tmpdiv;
long bestrate = -ERANGE;
unsigned long bestdiv;
unsigned long bestmul;
int i = 0;
/* Check if parent_rate is a valid input rate */
if (parent_rate < characteristics->input.min)
return -ERANGE;
/*
* Calculate minimum divider based on the minimum multiplier, the
* parent_rate and the requested rate.
* Should always be 2 according to the input and output characteristics
* of the PLL blocks.
*/
mindiv = (parent_rate * PLL_MUL_MIN) / rate;
if (!mindiv)
mindiv = 1;
if (parent_rate > characteristics->input.max) {
tmpdiv = DIV_ROUND_UP(parent_rate, characteristics->input.max);
if (tmpdiv > PLL_DIV_MAX)
return -ERANGE;
if (tmpdiv > mindiv)
mindiv = tmpdiv;
}
/*
* Calculate the maximum divider which is limited by PLL register
* layout (limited by the MUL or DIV field size).
*/
maxdiv = DIV_ROUND_UP(parent_rate * PLL_MUL_MAX(layout), rate);
if (maxdiv > PLL_DIV_MAX)
maxdiv = PLL_DIV_MAX;
/*
* Iterate over the acceptable divider values to find the best
* divider/multiplier pair (the one that generates the closest
* rate to the requested one).
*/
for (tmpdiv = mindiv; tmpdiv <= maxdiv; tmpdiv++) {
unsigned long remainder;
unsigned long tmprate;
unsigned long tmpmul;
/*
* Calculate the multiplier associated with the current
* divider that provide the closest rate to the requested one.
*/
tmpmul = DIV_ROUND_CLOSEST(rate, parent_rate / tmpdiv);
tmprate = (parent_rate / tmpdiv) * tmpmul;
if (tmprate > rate)
remainder = tmprate - rate;
else
remainder = rate - tmprate;
/*
* Compare the remainder with the best remainder found until
* now and elect a new best multiplier/divider pair if the
* current remainder is smaller than the best one.
*/
if (remainder < bestremainder) {
bestremainder = remainder;
bestdiv = tmpdiv;
bestmul = tmpmul;
bestrate = tmprate;
}
/*
* We've found a perfect match!
* Stop searching now and use this multiplier/divider pair.
*/
if (!remainder)
break;
}
/* We haven't found any multiplier/divider pair => return -ERANGE */
if (bestrate < 0)
return bestrate;
/* Check if bestrate is a valid output rate */
for (i = 0; i < characteristics->num_output; i++) {
if (bestrate >= characteristics->output[i].min &&
bestrate <= characteristics->output[i].max)
break;
}
if (i >= characteristics->num_output)
return -ERANGE;
if (div)
*div = bestdiv;
if (mul)
*mul = bestmul - 1;
if (index)
*index = i;
return bestrate;
}
static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct clk_pll *pll = to_clk_pll(hw);
return clk_pll_get_best_div_mul(pll, rate, *parent_rate,
NULL, NULL, NULL);
}
static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_pll *pll = to_clk_pll(hw);
long ret;
u32 div;
u32 mul;
u32 index;
ret = clk_pll_get_best_div_mul(pll, rate, parent_rate,
&div, &mul, &index);
if (ret < 0)
return ret;
pll->range = index;
pll->div = div;
pll->mul = mul;
return 0;
}
static int clk_pll_save_context(struct clk_hw *hw)
{
struct clk_pll *pll = to_clk_pll(hw);
struct clk_hw *parent_hw = clk_hw_get_parent(hw);
pll->pms.parent_rate = clk_hw_get_rate(parent_hw);
pll->pms.rate = clk_pll_recalc_rate(&pll->hw, pll->pms.parent_rate);
pll->pms.status = clk_pll_ready(pll->regmap, PLL_REG(pll->id));
return 0;
}
static void clk_pll_restore_context(struct clk_hw *hw)
{
struct clk_pll *pll = to_clk_pll(hw);
unsigned long calc_rate;
unsigned int pllr, pllr_out, pllr_count;
u8 out = 0;
if (pll->characteristics->out)
out = pll->characteristics->out[pll->range];
regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
calc_rate = (pll->pms.parent_rate / PLL_DIV(pllr)) *
(PLL_MUL(pllr, pll->layout) + 1);
pllr_count = (pllr >> PLL_COUNT_SHIFT) & PLL_MAX_COUNT;
pllr_out = (pllr >> PLL_OUT_SHIFT) & out;
if (pll->pms.rate != calc_rate ||
pll->pms.status != clk_pll_ready(pll->regmap, PLL_REG(pll->id)) ||
pllr_count != PLL_MAX_COUNT ||
(out && pllr_out != out))
pr_warn("PLLAR was not configured properly by firmware\n");
}
static const struct clk_ops pll_ops = {
.prepare = clk_pll_prepare,
.unprepare = clk_pll_unprepare,
.is_prepared = clk_pll_is_prepared,
.recalc_rate = clk_pll_recalc_rate,
.round_rate = clk_pll_round_rate,
.set_rate = clk_pll_set_rate,
.save_context = clk_pll_save_context,
.restore_context = clk_pll_restore_context,
};
struct clk_hw * __init
at91_clk_register_pll(struct regmap *regmap, const char *name,
const char *parent_name, u8 id,
const struct clk_pll_layout *layout,
const struct clk_pll_characteristics *characteristics)
{
struct clk_pll *pll;
struct clk_hw *hw;
struct clk_init_data init;
int offset = PLL_REG(id);
unsigned int pllr;
int ret;
if (id > PLL_MAX_ID)
return ERR_PTR(-EINVAL);
pll = kzalloc(sizeof(*pll), GFP_KERNEL);
if (!pll)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &pll_ops;
init.parent_names = &parent_name;
init.num_parents = 1;
init.flags = CLK_SET_RATE_GATE;
pll->id = id;
pll->hw.init = &init;
pll->layout = layout;
pll->characteristics = characteristics;
pll->regmap = regmap;
regmap_read(regmap, offset, &pllr);
pll->div = PLL_DIV(pllr);
pll->mul = PLL_MUL(pllr, layout);
hw = &pll->hw;
ret = clk_hw_register(NULL, &pll->hw);
if (ret) {
kfree(pll);
hw = ERR_PTR(ret);
}
return hw;
}
const struct clk_pll_layout at91rm9200_pll_layout = {
.pllr_mask = 0x7FFFFFF,
.mul_shift = 16,
.mul_mask = 0x7FF,
};
const struct clk_pll_layout at91sam9g45_pll_layout = {
.pllr_mask = 0xFFFFFF,
.mul_shift = 16,
.mul_mask = 0xFF,
};
const struct clk_pll_layout at91sam9g20_pllb_layout = {
.pllr_mask = 0x3FFFFF,
.mul_shift = 16,
.mul_mask = 0x3F,
};
const struct clk_pll_layout sama5d3_pll_layout = {
.pllr_mask = 0x1FFFFFF,
.mul_shift = 18,
.mul_mask = 0x7F,
};