linux/drivers/clk/imx/clk-pll14xx.c
Sascha Hauer b09c68dc57 clk: imx: pll14xx: Support dynamic rates
The pll1443x PLL so far only supports rates from a rate table passed
during initialization. Calculating PLL settings dynamically helps audio
applications to get their desired rates, so support for this is added
in this patch.

The strategy to get to the PLL setting for a rate is:

- First try to only adjust kdiv which specifies the fractional part of the PLL.
  This setting can be changed without glitches on the output and is therefore
  preferred
- When that isn't possible then the rate table is searched for suitable rates,
  so for standard rates the same settings are used as without this patch
- As a last resort the best settings are calculated dynamically

The code in this patch is based on patches from Adrian Alonso <adrian.alonso@nxp.com>
and Mads Bligaard Nielsen <bli@bang-olufsen.dk>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Link: https://lore.kernel.org/r/20220304125256.2125023-9-s.hauer@pengutronix.de
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
2022-03-04 17:06:30 +02:00

545 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2017-2018 NXP.
*/
#define pr_fmt(fmt) "pll14xx: " fmt
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include "clk.h"
#define GNRL_CTL 0x0
#define DIV_CTL0 0x4
#define DIV_CTL1 0x8
#define LOCK_STATUS BIT(31)
#define LOCK_SEL_MASK BIT(29)
#define CLKE_MASK BIT(11)
#define RST_MASK BIT(9)
#define BYPASS_MASK BIT(4)
#define MDIV_MASK GENMASK(21, 12)
#define PDIV_MASK GENMASK(9, 4)
#define SDIV_MASK GENMASK(2, 0)
#define KDIV_MASK GENMASK(15, 0)
#define KDIV_MIN SHRT_MIN
#define KDIV_MAX SHRT_MAX
#define LOCK_TIMEOUT_US 10000
struct clk_pll14xx {
struct clk_hw hw;
void __iomem *base;
enum imx_pll14xx_type type;
const struct imx_pll14xx_rate_table *rate_table;
int rate_count;
};
#define to_clk_pll14xx(_hw) container_of(_hw, struct clk_pll14xx, hw)
static const struct imx_pll14xx_rate_table imx_pll1416x_tbl[] = {
PLL_1416X_RATE(1800000000U, 225, 3, 0),
PLL_1416X_RATE(1600000000U, 200, 3, 0),
PLL_1416X_RATE(1500000000U, 375, 3, 1),
PLL_1416X_RATE(1400000000U, 350, 3, 1),
PLL_1416X_RATE(1200000000U, 300, 3, 1),
PLL_1416X_RATE(1000000000U, 250, 3, 1),
PLL_1416X_RATE(800000000U, 200, 3, 1),
PLL_1416X_RATE(750000000U, 250, 2, 2),
PLL_1416X_RATE(700000000U, 350, 3, 2),
PLL_1416X_RATE(600000000U, 300, 3, 2),
};
static const struct imx_pll14xx_rate_table imx_pll1443x_tbl[] = {
PLL_1443X_RATE(1039500000U, 173, 2, 1, 16384),
PLL_1443X_RATE(650000000U, 325, 3, 2, 0),
PLL_1443X_RATE(594000000U, 198, 2, 2, 0),
PLL_1443X_RATE(519750000U, 173, 2, 2, 16384),
PLL_1443X_RATE(393216000U, 262, 2, 3, 9437),
PLL_1443X_RATE(361267200U, 361, 3, 3, 17511),
};
struct imx_pll14xx_clk imx_1443x_pll = {
.type = PLL_1443X,
.rate_table = imx_pll1443x_tbl,
.rate_count = ARRAY_SIZE(imx_pll1443x_tbl),
};
EXPORT_SYMBOL_GPL(imx_1443x_pll);
struct imx_pll14xx_clk imx_1443x_dram_pll = {
.type = PLL_1443X,
.rate_table = imx_pll1443x_tbl,
.rate_count = ARRAY_SIZE(imx_pll1443x_tbl),
.flags = CLK_GET_RATE_NOCACHE,
};
EXPORT_SYMBOL_GPL(imx_1443x_dram_pll);
struct imx_pll14xx_clk imx_1416x_pll = {
.type = PLL_1416X,
.rate_table = imx_pll1416x_tbl,
.rate_count = ARRAY_SIZE(imx_pll1416x_tbl),
};
EXPORT_SYMBOL_GPL(imx_1416x_pll);
static const struct imx_pll14xx_rate_table *imx_get_pll_settings(
struct clk_pll14xx *pll, unsigned long rate)
{
const struct imx_pll14xx_rate_table *rate_table = pll->rate_table;
int i;
for (i = 0; i < pll->rate_count; i++)
if (rate == rate_table[i].rate)
return &rate_table[i];
return NULL;
}
static long pll14xx_calc_rate(struct clk_pll14xx *pll, int mdiv, int pdiv,
int sdiv, int kdiv, unsigned long prate)
{
u64 fvco = prate;
/* fvco = (m * 65536 + k) * Fin / (p * 65536) */
fvco *= (mdiv * 65536 + kdiv);
pdiv *= 65536;
do_div(fvco, pdiv << sdiv);
return fvco;
}
static long pll1443x_calc_kdiv(int mdiv, int pdiv, int sdiv,
unsigned long rate, unsigned long prate)
{
long kdiv;
/* calc kdiv = round(rate * pdiv * 65536 * 2^sdiv / prate) - (mdiv * 65536) */
kdiv = ((rate * ((pdiv * 65536) << sdiv) + prate / 2) / prate) - (mdiv * 65536);
return clamp_t(short, kdiv, KDIV_MIN, KDIV_MAX);
}
static void imx_pll14xx_calc_settings(struct clk_pll14xx *pll, unsigned long rate,
unsigned long prate, struct imx_pll14xx_rate_table *t)
{
u32 pll_div_ctl0, pll_div_ctl1;
int mdiv, pdiv, sdiv, kdiv;
long fvco, rate_min, rate_max, dist, best = LONG_MAX;
const struct imx_pll14xx_rate_table *tt;
/*
* Fractional PLL constrains:
*
* a) 6MHz <= prate <= 25MHz
* b) 1 <= p <= 63 (1 <= p <= 4 prate = 24MHz)
* c) 64 <= m <= 1023
* d) 0 <= s <= 6
* e) -32768 <= k <= 32767
*
* fvco = (m * 65536 + k) * prate / (p * 65536)
*/
/* First try if we can get the desired rate from one of the static entries */
tt = imx_get_pll_settings(pll, rate);
if (tt) {
pr_debug("%s: in=%ld, want=%ld, Using PLL setting from table\n",
clk_hw_get_name(&pll->hw), prate, rate);
t->rate = tt->rate;
t->mdiv = tt->mdiv;
t->pdiv = tt->pdiv;
t->sdiv = tt->sdiv;
t->kdiv = tt->kdiv;
return;
}
pll_div_ctl0 = readl_relaxed(pll->base + DIV_CTL0);
mdiv = FIELD_GET(MDIV_MASK, pll_div_ctl0);
pdiv = FIELD_GET(PDIV_MASK, pll_div_ctl0);
sdiv = FIELD_GET(SDIV_MASK, pll_div_ctl0);
pll_div_ctl1 = readl_relaxed(pll->base + DIV_CTL1);
/* Then see if we can get the desired rate by only adjusting kdiv (glitch free) */
rate_min = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, KDIV_MIN, prate);
rate_max = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, KDIV_MAX, prate);
if (rate >= rate_min && rate <= rate_max) {
kdiv = pll1443x_calc_kdiv(mdiv, pdiv, sdiv, rate, prate);
pr_debug("%s: in=%ld, want=%ld Only adjust kdiv %ld -> %d\n",
clk_hw_get_name(&pll->hw), prate, rate,
FIELD_GET(KDIV_MASK, pll_div_ctl1), kdiv);
fvco = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, kdiv, prate);
t->rate = (unsigned int)fvco;
t->mdiv = mdiv;
t->pdiv = pdiv;
t->sdiv = sdiv;
t->kdiv = kdiv;
return;
}
/* Finally calculate best values */
for (pdiv = 1; pdiv <= 7; pdiv++) {
for (sdiv = 0; sdiv <= 6; sdiv++) {
/* calc mdiv = round(rate * pdiv * 2^sdiv) / prate) */
mdiv = DIV_ROUND_CLOSEST(rate * (pdiv << sdiv), prate);
mdiv = clamp(mdiv, 64, 1023);
kdiv = pll1443x_calc_kdiv(mdiv, pdiv, sdiv, rate, prate);
fvco = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, kdiv, prate);
/* best match */
dist = abs((long)rate - (long)fvco);
if (dist < best) {
best = dist;
t->rate = (unsigned int)fvco;
t->mdiv = mdiv;
t->pdiv = pdiv;
t->sdiv = sdiv;
t->kdiv = kdiv;
if (!dist)
goto found;
}
}
}
found:
pr_debug("%s: in=%ld, want=%ld got=%d (pdiv=%d sdiv=%d mdiv=%d kdiv=%d)\n",
clk_hw_get_name(&pll->hw), prate, rate, t->rate, t->pdiv, t->sdiv,
t->mdiv, t->kdiv);
}
static long clk_pll1416x_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
const struct imx_pll14xx_rate_table *rate_table = pll->rate_table;
int i;
/* Assuming rate_table is in descending order */
for (i = 0; i < pll->rate_count; i++)
if (rate >= rate_table[i].rate)
return rate_table[i].rate;
/* return minimum supported value */
return rate_table[pll->rate_count - 1].rate;
}
static long clk_pll1443x_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
struct imx_pll14xx_rate_table t;
imx_pll14xx_calc_settings(pll, rate, *prate, &t);
return t.rate;
}
static unsigned long clk_pll14xx_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
u32 mdiv, pdiv, sdiv, kdiv, pll_div_ctl0, pll_div_ctl1;
pll_div_ctl0 = readl_relaxed(pll->base + DIV_CTL0);
mdiv = FIELD_GET(MDIV_MASK, pll_div_ctl0);
pdiv = FIELD_GET(PDIV_MASK, pll_div_ctl0);
sdiv = FIELD_GET(SDIV_MASK, pll_div_ctl0);
if (pll->type == PLL_1443X) {
pll_div_ctl1 = readl_relaxed(pll->base + DIV_CTL1);
kdiv = FIELD_GET(KDIV_MASK, pll_div_ctl1);
} else {
kdiv = 0;
}
return pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, kdiv, parent_rate);
}
static inline bool clk_pll14xx_mp_change(const struct imx_pll14xx_rate_table *rate,
u32 pll_div)
{
u32 old_mdiv, old_pdiv;
old_mdiv = FIELD_GET(MDIV_MASK, pll_div);
old_pdiv = FIELD_GET(PDIV_MASK, pll_div);
return rate->mdiv != old_mdiv || rate->pdiv != old_pdiv;
}
static int clk_pll14xx_wait_lock(struct clk_pll14xx *pll)
{
u32 val;
return readl_poll_timeout(pll->base + GNRL_CTL, val, val & LOCK_STATUS, 0,
LOCK_TIMEOUT_US);
}
static int clk_pll1416x_set_rate(struct clk_hw *hw, unsigned long drate,
unsigned long prate)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
const struct imx_pll14xx_rate_table *rate;
u32 tmp, div_val;
int ret;
rate = imx_get_pll_settings(pll, drate);
if (!rate) {
pr_err("Invalid rate %lu for pll clk %s\n", drate,
clk_hw_get_name(hw));
return -EINVAL;
}
tmp = readl_relaxed(pll->base + DIV_CTL0);
if (!clk_pll14xx_mp_change(rate, tmp)) {
tmp &= ~SDIV_MASK;
tmp |= FIELD_PREP(SDIV_MASK, rate->sdiv);
writel_relaxed(tmp, pll->base + DIV_CTL0);
return 0;
}
/* Bypass clock and set lock to pll output lock */
tmp = readl_relaxed(pll->base + GNRL_CTL);
tmp |= LOCK_SEL_MASK;
writel_relaxed(tmp, pll->base + GNRL_CTL);
/* Enable RST */
tmp &= ~RST_MASK;
writel_relaxed(tmp, pll->base + GNRL_CTL);
/* Enable BYPASS */
tmp |= BYPASS_MASK;
writel(tmp, pll->base + GNRL_CTL);
div_val = FIELD_PREP(MDIV_MASK, rate->mdiv) | FIELD_PREP(PDIV_MASK, rate->pdiv) |
FIELD_PREP(SDIV_MASK, rate->sdiv);
writel_relaxed(div_val, pll->base + DIV_CTL0);
/*
* According to SPEC, t3 - t2 need to be greater than
* 1us and 1/FREF, respectively.
* FREF is FIN / Prediv, the prediv is [1, 63], so choose
* 3us.
*/
udelay(3);
/* Disable RST */
tmp |= RST_MASK;
writel_relaxed(tmp, pll->base + GNRL_CTL);
/* Wait Lock */
ret = clk_pll14xx_wait_lock(pll);
if (ret)
return ret;
/* Bypass */
tmp &= ~BYPASS_MASK;
writel_relaxed(tmp, pll->base + GNRL_CTL);
return 0;
}
static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate,
unsigned long prate)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
struct imx_pll14xx_rate_table rate;
u32 gnrl_ctl, div_ctl0;
int ret;
imx_pll14xx_calc_settings(pll, drate, prate, &rate);
div_ctl0 = readl_relaxed(pll->base + DIV_CTL0);
if (!clk_pll14xx_mp_change(&rate, div_ctl0)) {
/* only sdiv and/or kdiv changed - no need to RESET PLL */
div_ctl0 &= ~SDIV_MASK;
div_ctl0 |= FIELD_PREP(SDIV_MASK, rate.sdiv);
writel_relaxed(div_ctl0, pll->base + DIV_CTL0);
writel_relaxed(FIELD_PREP(KDIV_MASK, rate.kdiv),
pll->base + DIV_CTL1);
return 0;
}
/* Enable RST */
gnrl_ctl = readl_relaxed(pll->base + GNRL_CTL);
gnrl_ctl &= ~RST_MASK;
writel_relaxed(gnrl_ctl, pll->base + GNRL_CTL);
/* Enable BYPASS */
gnrl_ctl |= BYPASS_MASK;
writel_relaxed(gnrl_ctl, pll->base + GNRL_CTL);
div_ctl0 = FIELD_PREP(MDIV_MASK, rate.mdiv) |
FIELD_PREP(PDIV_MASK, rate.pdiv) |
FIELD_PREP(SDIV_MASK, rate.sdiv);
writel_relaxed(div_ctl0, pll->base + DIV_CTL0);
writel_relaxed(FIELD_PREP(KDIV_MASK, rate.kdiv), pll->base + DIV_CTL1);
/*
* According to SPEC, t3 - t2 need to be greater than
* 1us and 1/FREF, respectively.
* FREF is FIN / Prediv, the prediv is [1, 63], so choose
* 3us.
*/
udelay(3);
/* Disable RST */
gnrl_ctl |= RST_MASK;
writel_relaxed(gnrl_ctl, pll->base + GNRL_CTL);
/* Wait Lock*/
ret = clk_pll14xx_wait_lock(pll);
if (ret)
return ret;
/* Bypass */
gnrl_ctl &= ~BYPASS_MASK;
writel_relaxed(gnrl_ctl, pll->base + GNRL_CTL);
return 0;
}
static int clk_pll14xx_prepare(struct clk_hw *hw)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
u32 val;
int ret;
/*
* RESETB = 1 from 0, PLL starts its normal
* operation after lock time
*/
val = readl_relaxed(pll->base + GNRL_CTL);
if (val & RST_MASK)
return 0;
val |= BYPASS_MASK;
writel_relaxed(val, pll->base + GNRL_CTL);
val |= RST_MASK;
writel_relaxed(val, pll->base + GNRL_CTL);
ret = clk_pll14xx_wait_lock(pll);
if (ret)
return ret;
val &= ~BYPASS_MASK;
writel_relaxed(val, pll->base + GNRL_CTL);
return 0;
}
static int clk_pll14xx_is_prepared(struct clk_hw *hw)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
u32 val;
val = readl_relaxed(pll->base + GNRL_CTL);
return (val & RST_MASK) ? 1 : 0;
}
static void clk_pll14xx_unprepare(struct clk_hw *hw)
{
struct clk_pll14xx *pll = to_clk_pll14xx(hw);
u32 val;
/*
* Set RST to 0, power down mode is enabled and
* every digital block is reset
*/
val = readl_relaxed(pll->base + GNRL_CTL);
val &= ~RST_MASK;
writel_relaxed(val, pll->base + GNRL_CTL);
}
static const struct clk_ops clk_pll1416x_ops = {
.prepare = clk_pll14xx_prepare,
.unprepare = clk_pll14xx_unprepare,
.is_prepared = clk_pll14xx_is_prepared,
.recalc_rate = clk_pll14xx_recalc_rate,
.round_rate = clk_pll1416x_round_rate,
.set_rate = clk_pll1416x_set_rate,
};
static const struct clk_ops clk_pll1416x_min_ops = {
.recalc_rate = clk_pll14xx_recalc_rate,
};
static const struct clk_ops clk_pll1443x_ops = {
.prepare = clk_pll14xx_prepare,
.unprepare = clk_pll14xx_unprepare,
.is_prepared = clk_pll14xx_is_prepared,
.recalc_rate = clk_pll14xx_recalc_rate,
.round_rate = clk_pll1443x_round_rate,
.set_rate = clk_pll1443x_set_rate,
};
struct clk_hw *imx_dev_clk_hw_pll14xx(struct device *dev, const char *name,
const char *parent_name, void __iomem *base,
const struct imx_pll14xx_clk *pll_clk)
{
struct clk_pll14xx *pll;
struct clk_hw *hw;
struct clk_init_data init;
int ret;
u32 val;
pll = kzalloc(sizeof(*pll), GFP_KERNEL);
if (!pll)
return ERR_PTR(-ENOMEM);
init.name = name;
init.flags = pll_clk->flags;
init.parent_names = &parent_name;
init.num_parents = 1;
switch (pll_clk->type) {
case PLL_1416X:
if (!pll_clk->rate_table)
init.ops = &clk_pll1416x_min_ops;
else
init.ops = &clk_pll1416x_ops;
break;
case PLL_1443X:
init.ops = &clk_pll1443x_ops;
break;
default:
pr_err("Unknown pll type for pll clk %s\n", name);
kfree(pll);
return ERR_PTR(-EINVAL);
}
pll->base = base;
pll->hw.init = &init;
pll->type = pll_clk->type;
pll->rate_table = pll_clk->rate_table;
pll->rate_count = pll_clk->rate_count;
val = readl_relaxed(pll->base + GNRL_CTL);
val &= ~BYPASS_MASK;
writel_relaxed(val, pll->base + GNRL_CTL);
hw = &pll->hw;
ret = clk_hw_register(dev, hw);
if (ret) {
pr_err("failed to register pll %s %d\n", name, ret);
kfree(pll);
return ERR_PTR(ret);
}
return hw;
}
EXPORT_SYMBOL_GPL(imx_dev_clk_hw_pll14xx);