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linux/drivers/clk/clk-axi-clkgen.c
Maxime Ripard 6222b494a9 clk: axi-clkgen: Switch to determine_rate 
The AXI clkgen clocks implements a mux with a set_parent hook, but
doesn't provide a determine_rate implementation.

This is a bit odd, since set_parent() is there to, as its name implies,
change the parent of a clock. However, the most likely candidate to
trigger that parent change is a call to clk_set_rate(), with
determine_rate() figuring out which parent is the best suited for a
given rate.

The other trigger would be a call to clk_set_parent(), but it's far less
used, and it doesn't look like there's any obvious user for that clock.

So, the set_parent hook is effectively unused, possibly because of an
oversight. However, it could also be an explicit decision by the
original author to avoid any reparenting but through an explicit call to
clk_set_parent().

The driver does implement round_rate() though, which means that we can
change the rate of the clock, but we will never get to change the
parent.

However, It's hard to tell whether it's been done on purpose or not.

Since we'll start mandating a determine_rate() implementation, let's
convert the round_rate() implementation to a determine_rate(), which
will also make the current behavior explicit. And if it was an
oversight, the clock behaviour can be adjusted later on.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-50-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2023-06-08 18:39:33 -07:00

587 lines
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// SPDX-License-Identifier: GPL-2.0-only
/*
* AXI clkgen driver
*
* Copyright 2012-2013 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*/
#include <linux/platform_device.h>
#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/err.h>
#define AXI_CLKGEN_V2_REG_RESET 0x40
#define AXI_CLKGEN_V2_REG_CLKSEL 0x44
#define AXI_CLKGEN_V2_REG_DRP_CNTRL 0x70
#define AXI_CLKGEN_V2_REG_DRP_STATUS 0x74
#define AXI_CLKGEN_V2_RESET_MMCM_ENABLE BIT(1)
#define AXI_CLKGEN_V2_RESET_ENABLE BIT(0)
#define AXI_CLKGEN_V2_DRP_CNTRL_SEL BIT(29)
#define AXI_CLKGEN_V2_DRP_CNTRL_READ BIT(28)
#define AXI_CLKGEN_V2_DRP_STATUS_BUSY BIT(16)
#define MMCM_REG_CLKOUT5_2 0x07
#define MMCM_REG_CLKOUT0_1 0x08
#define MMCM_REG_CLKOUT0_2 0x09
#define MMCM_REG_CLKOUT6_2 0x13
#define MMCM_REG_CLK_FB1 0x14
#define MMCM_REG_CLK_FB2 0x15
#define MMCM_REG_CLK_DIV 0x16
#define MMCM_REG_LOCK1 0x18
#define MMCM_REG_LOCK2 0x19
#define MMCM_REG_LOCK3 0x1a
#define MMCM_REG_POWER 0x28
#define MMCM_REG_FILTER1 0x4e
#define MMCM_REG_FILTER2 0x4f
#define MMCM_CLKOUT_NOCOUNT BIT(6)
#define MMCM_CLK_DIV_DIVIDE BIT(11)
#define MMCM_CLK_DIV_NOCOUNT BIT(12)
struct axi_clkgen_limits {
unsigned int fpfd_min;
unsigned int fpfd_max;
unsigned int fvco_min;
unsigned int fvco_max;
};
struct axi_clkgen {
void __iomem *base;
struct clk_hw clk_hw;
struct axi_clkgen_limits limits;
};
static uint32_t axi_clkgen_lookup_filter(unsigned int m)
{
switch (m) {
case 0:
return 0x01001990;
case 1:
return 0x01001190;
case 2:
return 0x01009890;
case 3:
return 0x01001890;
case 4:
return 0x01008890;
case 5 ... 8:
return 0x01009090;
case 9 ... 11:
return 0x01000890;
case 12:
return 0x08009090;
case 13 ... 22:
return 0x01001090;
case 23 ... 36:
return 0x01008090;
case 37 ... 46:
return 0x08001090;
default:
return 0x08008090;
}
}
static const uint32_t axi_clkgen_lock_table[] = {
0x060603e8, 0x060603e8, 0x080803e8, 0x0b0b03e8,
0x0e0e03e8, 0x111103e8, 0x131303e8, 0x161603e8,
0x191903e8, 0x1c1c03e8, 0x1f1f0384, 0x1f1f0339,
0x1f1f02ee, 0x1f1f02bc, 0x1f1f028a, 0x1f1f0271,
0x1f1f023f, 0x1f1f0226, 0x1f1f020d, 0x1f1f01f4,
0x1f1f01db, 0x1f1f01c2, 0x1f1f01a9, 0x1f1f0190,
0x1f1f0190, 0x1f1f0177, 0x1f1f015e, 0x1f1f015e,
0x1f1f0145, 0x1f1f0145, 0x1f1f012c, 0x1f1f012c,
0x1f1f012c, 0x1f1f0113, 0x1f1f0113, 0x1f1f0113,
};
static uint32_t axi_clkgen_lookup_lock(unsigned int m)
{
if (m < ARRAY_SIZE(axi_clkgen_lock_table))
return axi_clkgen_lock_table[m];
return 0x1f1f00fa;
}
static const struct axi_clkgen_limits axi_clkgen_zynqmp_default_limits = {
.fpfd_min = 10000,
.fpfd_max = 450000,
.fvco_min = 800000,
.fvco_max = 1600000,
};
static const struct axi_clkgen_limits axi_clkgen_zynq_default_limits = {
.fpfd_min = 10000,
.fpfd_max = 300000,
.fvco_min = 600000,
.fvco_max = 1200000,
};
static void axi_clkgen_calc_params(const struct axi_clkgen_limits *limits,
unsigned long fin, unsigned long fout,
unsigned int *best_d, unsigned int *best_m, unsigned int *best_dout)
{
unsigned long d, d_min, d_max, _d_min, _d_max;
unsigned long m, m_min, m_max;
unsigned long f, dout, best_f, fvco;
unsigned long fract_shift = 0;
unsigned long fvco_min_fract, fvco_max_fract;
fin /= 1000;
fout /= 1000;
best_f = ULONG_MAX;
*best_d = 0;
*best_m = 0;
*best_dout = 0;
d_min = max_t(unsigned long, DIV_ROUND_UP(fin, limits->fpfd_max), 1);
d_max = min_t(unsigned long, fin / limits->fpfd_min, 80);
again:
fvco_min_fract = limits->fvco_min << fract_shift;
fvco_max_fract = limits->fvco_max << fract_shift;
m_min = max_t(unsigned long, DIV_ROUND_UP(fvco_min_fract, fin) * d_min, 1);
m_max = min_t(unsigned long, fvco_max_fract * d_max / fin, 64 << fract_shift);
for (m = m_min; m <= m_max; m++) {
_d_min = max(d_min, DIV_ROUND_UP(fin * m, fvco_max_fract));
_d_max = min(d_max, fin * m / fvco_min_fract);
for (d = _d_min; d <= _d_max; d++) {
fvco = fin * m / d;
dout = DIV_ROUND_CLOSEST(fvco, fout);
dout = clamp_t(unsigned long, dout, 1, 128 << fract_shift);
f = fvco / dout;
if (abs(f - fout) < abs(best_f - fout)) {
best_f = f;
*best_d = d;
*best_m = m << (3 - fract_shift);
*best_dout = dout << (3 - fract_shift);
if (best_f == fout)
return;
}
}
}
/* Lets see if we find a better setting in fractional mode */
if (fract_shift == 0) {
fract_shift = 3;
goto again;
}
}
struct axi_clkgen_div_params {
unsigned int low;
unsigned int high;
unsigned int edge;
unsigned int nocount;
unsigned int frac_en;
unsigned int frac;
unsigned int frac_wf_f;
unsigned int frac_wf_r;
unsigned int frac_phase;
};
static void axi_clkgen_calc_clk_params(unsigned int divider,
unsigned int frac_divider, struct axi_clkgen_div_params *params)
{
memset(params, 0x0, sizeof(*params));
if (divider == 1) {
params->nocount = 1;
return;
}
if (frac_divider == 0) {
params->high = divider / 2;
params->edge = divider % 2;
params->low = divider - params->high;
} else {
params->frac_en = 1;
params->frac = frac_divider;
params->high = divider / 2;
params->edge = divider % 2;
params->low = params->high;
if (params->edge == 0) {
params->high--;
params->frac_wf_r = 1;
}
if (params->edge == 0 || frac_divider == 1)
params->low--;
if (((params->edge == 0) ^ (frac_divider == 1)) ||
(divider == 2 && frac_divider == 1))
params->frac_wf_f = 1;
params->frac_phase = params->edge * 4 + frac_divider / 2;
}
}
static void axi_clkgen_write(struct axi_clkgen *axi_clkgen,
unsigned int reg, unsigned int val)
{
writel(val, axi_clkgen->base + reg);
}
static void axi_clkgen_read(struct axi_clkgen *axi_clkgen,
unsigned int reg, unsigned int *val)
{
*val = readl(axi_clkgen->base + reg);
}
static int axi_clkgen_wait_non_busy(struct axi_clkgen *axi_clkgen)
{
unsigned int timeout = 10000;
unsigned int val;
do {
axi_clkgen_read(axi_clkgen, AXI_CLKGEN_V2_REG_DRP_STATUS, &val);
} while ((val & AXI_CLKGEN_V2_DRP_STATUS_BUSY) && --timeout);
if (val & AXI_CLKGEN_V2_DRP_STATUS_BUSY)
return -EIO;
return val & 0xffff;
}
static int axi_clkgen_mmcm_read(struct axi_clkgen *axi_clkgen,
unsigned int reg, unsigned int *val)
{
unsigned int reg_val;
int ret;
ret = axi_clkgen_wait_non_busy(axi_clkgen);
if (ret < 0)
return ret;
reg_val = AXI_CLKGEN_V2_DRP_CNTRL_SEL | AXI_CLKGEN_V2_DRP_CNTRL_READ;
reg_val |= (reg << 16);
axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_DRP_CNTRL, reg_val);
ret = axi_clkgen_wait_non_busy(axi_clkgen);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int axi_clkgen_mmcm_write(struct axi_clkgen *axi_clkgen,
unsigned int reg, unsigned int val, unsigned int mask)
{
unsigned int reg_val = 0;
int ret;
ret = axi_clkgen_wait_non_busy(axi_clkgen);
if (ret < 0)
return ret;
if (mask != 0xffff) {
axi_clkgen_mmcm_read(axi_clkgen, reg, &reg_val);
reg_val &= ~mask;
}
reg_val |= AXI_CLKGEN_V2_DRP_CNTRL_SEL | (reg << 16) | (val & mask);
axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_DRP_CNTRL, reg_val);
return 0;
}
static void axi_clkgen_mmcm_enable(struct axi_clkgen *axi_clkgen,
bool enable)
{
unsigned int val = AXI_CLKGEN_V2_RESET_ENABLE;
if (enable)
val |= AXI_CLKGEN_V2_RESET_MMCM_ENABLE;
axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_RESET, val);
}
static struct axi_clkgen *clk_hw_to_axi_clkgen(struct clk_hw *clk_hw)
{
return container_of(clk_hw, struct axi_clkgen, clk_hw);
}
static void axi_clkgen_set_div(struct axi_clkgen *axi_clkgen,
unsigned int reg1, unsigned int reg2, unsigned int reg3,
struct axi_clkgen_div_params *params)
{
axi_clkgen_mmcm_write(axi_clkgen, reg1,
(params->high << 6) | params->low, 0xefff);
axi_clkgen_mmcm_write(axi_clkgen, reg2,
(params->frac << 12) | (params->frac_en << 11) |
(params->frac_wf_r << 10) | (params->edge << 7) |
(params->nocount << 6), 0x7fff);
if (reg3 != 0) {
axi_clkgen_mmcm_write(axi_clkgen, reg3,
(params->frac_phase << 11) | (params->frac_wf_f << 10), 0x3c00);
}
}
static int axi_clkgen_set_rate(struct clk_hw *clk_hw,
unsigned long rate, unsigned long parent_rate)
{
struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
const struct axi_clkgen_limits *limits = &axi_clkgen->limits;
unsigned int d, m, dout;
struct axi_clkgen_div_params params;
uint32_t power = 0;
uint32_t filter;
uint32_t lock;
if (parent_rate == 0 || rate == 0)
return -EINVAL;
axi_clkgen_calc_params(limits, parent_rate, rate, &d, &m, &dout);
if (d == 0 || dout == 0 || m == 0)
return -EINVAL;
if ((dout & 0x7) != 0 || (m & 0x7) != 0)
power |= 0x9800;
axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_POWER, power, 0x9800);
filter = axi_clkgen_lookup_filter(m - 1);
lock = axi_clkgen_lookup_lock(m - 1);
axi_clkgen_calc_clk_params(dout >> 3, dout & 0x7, &params);
axi_clkgen_set_div(axi_clkgen, MMCM_REG_CLKOUT0_1, MMCM_REG_CLKOUT0_2,
MMCM_REG_CLKOUT5_2, &params);
axi_clkgen_calc_clk_params(d, 0, &params);
axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_CLK_DIV,
(params.edge << 13) | (params.nocount << 12) |
(params.high << 6) | params.low, 0x3fff);
axi_clkgen_calc_clk_params(m >> 3, m & 0x7, &params);
axi_clkgen_set_div(axi_clkgen, MMCM_REG_CLK_FB1, MMCM_REG_CLK_FB2,
MMCM_REG_CLKOUT6_2, &params);
axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_LOCK1, lock & 0x3ff, 0x3ff);
axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_LOCK2,
(((lock >> 16) & 0x1f) << 10) | 0x1, 0x7fff);
axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_LOCK3,
(((lock >> 24) & 0x1f) << 10) | 0x3e9, 0x7fff);
axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_FILTER1, filter >> 16, 0x9900);
axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_FILTER2, filter, 0x9900);
return 0;
}
static int axi_clkgen_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(hw);
const struct axi_clkgen_limits *limits = &axi_clkgen->limits;
unsigned int d, m, dout;
unsigned long long tmp;
axi_clkgen_calc_params(limits, req->best_parent_rate, req->rate,
&d, &m, &dout);
if (d == 0 || dout == 0 || m == 0)
return -EINVAL;
tmp = (unsigned long long)req->best_parent_rate * m;
tmp = DIV_ROUND_CLOSEST_ULL(tmp, dout * d);
req->rate = min_t(unsigned long long, tmp, LONG_MAX);
return 0;
}
static unsigned int axi_clkgen_get_div(struct axi_clkgen *axi_clkgen,
unsigned int reg1, unsigned int reg2)
{
unsigned int val1, val2;
unsigned int div;
axi_clkgen_mmcm_read(axi_clkgen, reg2, &val2);
if (val2 & MMCM_CLKOUT_NOCOUNT)
return 8;
axi_clkgen_mmcm_read(axi_clkgen, reg1, &val1);
div = (val1 & 0x3f) + ((val1 >> 6) & 0x3f);
div <<= 3;
if (val2 & MMCM_CLK_DIV_DIVIDE) {
if ((val2 & BIT(7)) && (val2 & 0x7000) != 0x1000)
div += 8;
else
div += 16;
div += (val2 >> 12) & 0x7;
}
return div;
}
static unsigned long axi_clkgen_recalc_rate(struct clk_hw *clk_hw,
unsigned long parent_rate)
{
struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
unsigned int d, m, dout;
unsigned long long tmp;
unsigned int val;
dout = axi_clkgen_get_div(axi_clkgen, MMCM_REG_CLKOUT0_1,
MMCM_REG_CLKOUT0_2);
m = axi_clkgen_get_div(axi_clkgen, MMCM_REG_CLK_FB1,
MMCM_REG_CLK_FB2);
axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLK_DIV, &val);
if (val & MMCM_CLK_DIV_NOCOUNT)
d = 1;
else
d = (val & 0x3f) + ((val >> 6) & 0x3f);
if (d == 0 || dout == 0)
return 0;
tmp = (unsigned long long)parent_rate * m;
tmp = DIV_ROUND_CLOSEST_ULL(tmp, dout * d);
return min_t(unsigned long long, tmp, ULONG_MAX);
}
static int axi_clkgen_enable(struct clk_hw *clk_hw)
{
struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
axi_clkgen_mmcm_enable(axi_clkgen, true);
return 0;
}
static void axi_clkgen_disable(struct clk_hw *clk_hw)
{
struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
axi_clkgen_mmcm_enable(axi_clkgen, false);
}
static int axi_clkgen_set_parent(struct clk_hw *clk_hw, u8 index)
{
struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_CLKSEL, index);
return 0;
}
static u8 axi_clkgen_get_parent(struct clk_hw *clk_hw)
{
struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
unsigned int parent;
axi_clkgen_read(axi_clkgen, AXI_CLKGEN_V2_REG_CLKSEL, &parent);
return parent;
}
static const struct clk_ops axi_clkgen_ops = {
.recalc_rate = axi_clkgen_recalc_rate,
.determine_rate = axi_clkgen_determine_rate,
.set_rate = axi_clkgen_set_rate,
.enable = axi_clkgen_enable,
.disable = axi_clkgen_disable,
.set_parent = axi_clkgen_set_parent,
.get_parent = axi_clkgen_get_parent,
};
static int axi_clkgen_probe(struct platform_device *pdev)
{
const struct axi_clkgen_limits *dflt_limits;
struct axi_clkgen *axi_clkgen;
struct clk_init_data init;
const char *parent_names[2];
const char *clk_name;
unsigned int i;
int ret;
dflt_limits = device_get_match_data(&pdev->dev);
if (!dflt_limits)
return -ENODEV;
axi_clkgen = devm_kzalloc(&pdev->dev, sizeof(*axi_clkgen), GFP_KERNEL);
if (!axi_clkgen)
return -ENOMEM;
axi_clkgen->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(axi_clkgen->base))
return PTR_ERR(axi_clkgen->base);
init.num_parents = of_clk_get_parent_count(pdev->dev.of_node);
if (init.num_parents < 1 || init.num_parents > 2)
return -EINVAL;
for (i = 0; i < init.num_parents; i++) {
parent_names[i] = of_clk_get_parent_name(pdev->dev.of_node, i);
if (!parent_names[i])
return -EINVAL;
}
memcpy(&axi_clkgen->limits, dflt_limits, sizeof(axi_clkgen->limits));
clk_name = pdev->dev.of_node->name;
of_property_read_string(pdev->dev.of_node, "clock-output-names",
&clk_name);
init.name = clk_name;
init.ops = &axi_clkgen_ops;
init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
init.parent_names = parent_names;
axi_clkgen_mmcm_enable(axi_clkgen, false);
axi_clkgen->clk_hw.init = &init;
ret = devm_clk_hw_register(&pdev->dev, &axi_clkgen->clk_hw);
if (ret)
return ret;
return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get,
&axi_clkgen->clk_hw);
}
static const struct of_device_id axi_clkgen_ids[] = {
{
.compatible = "adi,zynqmp-axi-clkgen-2.00.a",
.data = &axi_clkgen_zynqmp_default_limits,
},
{
.compatible = "adi,axi-clkgen-2.00.a",
.data = &axi_clkgen_zynq_default_limits,
},
{ }
};
MODULE_DEVICE_TABLE(of, axi_clkgen_ids);
static struct platform_driver axi_clkgen_driver = {
.driver = {
.name = "adi-axi-clkgen",
.of_match_table = axi_clkgen_ids,
},
.probe = axi_clkgen_probe,
};
module_platform_driver(axi_clkgen_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Driver for the Analog Devices' AXI clkgen pcore clock generator");
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