linux-stable/drivers/clk/at91/sckc.c
Claudiu Beznea e1e3e7008a clk: at91: sckc: register slow_rc with accuracy option
Chapter 57.7.5 of SAM9X60 datasheet specifies that the maximum drift of
this oscillator is +- 3KHz. Use that value and the formula at [1]
or the calculator at [2] to compute the PPB value.

[1] https://www.everythingrf.com/rf-calculators/ppm-to-hz-calculator
[2] https://www.changpuak.ch/electronics/ppm_to_Hz_converter.php

Fixes: 04bcc4275e ("clk: at91: sckc: add support for SAM9X60")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1595403506-8209-9-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-07-24 02:19:08 -07:00

633 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* drivers/clk/at91/sckc.c
*
* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
*/
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/io.h>
#define SLOW_CLOCK_FREQ 32768
#define SLOWCK_SW_CYCLES 5
#define SLOWCK_SW_TIME_USEC ((SLOWCK_SW_CYCLES * USEC_PER_SEC) / \
SLOW_CLOCK_FREQ)
#define AT91_SCKC_CR 0x00
struct clk_slow_bits {
u32 cr_rcen;
u32 cr_osc32en;
u32 cr_osc32byp;
u32 cr_oscsel;
};
struct clk_slow_osc {
struct clk_hw hw;
void __iomem *sckcr;
const struct clk_slow_bits *bits;
unsigned long startup_usec;
};
#define to_clk_slow_osc(hw) container_of(hw, struct clk_slow_osc, hw)
struct clk_sama5d4_slow_osc {
struct clk_hw hw;
void __iomem *sckcr;
const struct clk_slow_bits *bits;
unsigned long startup_usec;
bool prepared;
};
#define to_clk_sama5d4_slow_osc(hw) container_of(hw, struct clk_sama5d4_slow_osc, hw)
struct clk_slow_rc_osc {
struct clk_hw hw;
void __iomem *sckcr;
const struct clk_slow_bits *bits;
unsigned long frequency;
unsigned long accuracy;
unsigned long startup_usec;
};
#define to_clk_slow_rc_osc(hw) container_of(hw, struct clk_slow_rc_osc, hw)
struct clk_sam9x5_slow {
struct clk_hw hw;
void __iomem *sckcr;
const struct clk_slow_bits *bits;
u8 parent;
};
#define to_clk_sam9x5_slow(hw) container_of(hw, struct clk_sam9x5_slow, hw)
static int clk_slow_osc_prepare(struct clk_hw *hw)
{
struct clk_slow_osc *osc = to_clk_slow_osc(hw);
void __iomem *sckcr = osc->sckcr;
u32 tmp = readl(sckcr);
if (tmp & (osc->bits->cr_osc32byp | osc->bits->cr_osc32en))
return 0;
writel(tmp | osc->bits->cr_osc32en, sckcr);
if (system_state < SYSTEM_RUNNING)
udelay(osc->startup_usec);
else
usleep_range(osc->startup_usec, osc->startup_usec + 1);
return 0;
}
static void clk_slow_osc_unprepare(struct clk_hw *hw)
{
struct clk_slow_osc *osc = to_clk_slow_osc(hw);
void __iomem *sckcr = osc->sckcr;
u32 tmp = readl(sckcr);
if (tmp & osc->bits->cr_osc32byp)
return;
writel(tmp & ~osc->bits->cr_osc32en, sckcr);
}
static int clk_slow_osc_is_prepared(struct clk_hw *hw)
{
struct clk_slow_osc *osc = to_clk_slow_osc(hw);
void __iomem *sckcr = osc->sckcr;
u32 tmp = readl(sckcr);
if (tmp & osc->bits->cr_osc32byp)
return 1;
return !!(tmp & osc->bits->cr_osc32en);
}
static const struct clk_ops slow_osc_ops = {
.prepare = clk_slow_osc_prepare,
.unprepare = clk_slow_osc_unprepare,
.is_prepared = clk_slow_osc_is_prepared,
};
static struct clk_hw * __init
at91_clk_register_slow_osc(void __iomem *sckcr,
const char *name,
const char *parent_name,
unsigned long startup,
bool bypass,
const struct clk_slow_bits *bits)
{
struct clk_slow_osc *osc;
struct clk_hw *hw;
struct clk_init_data init;
int ret;
if (!sckcr || !name || !parent_name)
return ERR_PTR(-EINVAL);
osc = kzalloc(sizeof(*osc), GFP_KERNEL);
if (!osc)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &slow_osc_ops;
init.parent_names = &parent_name;
init.num_parents = 1;
init.flags = CLK_IGNORE_UNUSED;
osc->hw.init = &init;
osc->sckcr = sckcr;
osc->startup_usec = startup;
osc->bits = bits;
if (bypass)
writel((readl(sckcr) & ~osc->bits->cr_osc32en) |
osc->bits->cr_osc32byp, sckcr);
hw = &osc->hw;
ret = clk_hw_register(NULL, &osc->hw);
if (ret) {
kfree(osc);
hw = ERR_PTR(ret);
}
return hw;
}
static void at91_clk_unregister_slow_osc(struct clk_hw *hw)
{
struct clk_slow_osc *osc = to_clk_slow_osc(hw);
clk_hw_unregister(hw);
kfree(osc);
}
static unsigned long clk_slow_rc_osc_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
return osc->frequency;
}
static unsigned long clk_slow_rc_osc_recalc_accuracy(struct clk_hw *hw,
unsigned long parent_acc)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
return osc->accuracy;
}
static int clk_slow_rc_osc_prepare(struct clk_hw *hw)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
void __iomem *sckcr = osc->sckcr;
writel(readl(sckcr) | osc->bits->cr_rcen, sckcr);
if (system_state < SYSTEM_RUNNING)
udelay(osc->startup_usec);
else
usleep_range(osc->startup_usec, osc->startup_usec + 1);
return 0;
}
static void clk_slow_rc_osc_unprepare(struct clk_hw *hw)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
void __iomem *sckcr = osc->sckcr;
writel(readl(sckcr) & ~osc->bits->cr_rcen, sckcr);
}
static int clk_slow_rc_osc_is_prepared(struct clk_hw *hw)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
return !!(readl(osc->sckcr) & osc->bits->cr_rcen);
}
static const struct clk_ops slow_rc_osc_ops = {
.prepare = clk_slow_rc_osc_prepare,
.unprepare = clk_slow_rc_osc_unprepare,
.is_prepared = clk_slow_rc_osc_is_prepared,
.recalc_rate = clk_slow_rc_osc_recalc_rate,
.recalc_accuracy = clk_slow_rc_osc_recalc_accuracy,
};
static struct clk_hw * __init
at91_clk_register_slow_rc_osc(void __iomem *sckcr,
const char *name,
unsigned long frequency,
unsigned long accuracy,
unsigned long startup,
const struct clk_slow_bits *bits)
{
struct clk_slow_rc_osc *osc;
struct clk_hw *hw;
struct clk_init_data init;
int ret;
if (!sckcr || !name)
return ERR_PTR(-EINVAL);
osc = kzalloc(sizeof(*osc), GFP_KERNEL);
if (!osc)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &slow_rc_osc_ops;
init.parent_names = NULL;
init.num_parents = 0;
init.flags = CLK_IGNORE_UNUSED;
osc->hw.init = &init;
osc->sckcr = sckcr;
osc->bits = bits;
osc->frequency = frequency;
osc->accuracy = accuracy;
osc->startup_usec = startup;
hw = &osc->hw;
ret = clk_hw_register(NULL, &osc->hw);
if (ret) {
kfree(osc);
hw = ERR_PTR(ret);
}
return hw;
}
static void at91_clk_unregister_slow_rc_osc(struct clk_hw *hw)
{
struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
clk_hw_unregister(hw);
kfree(osc);
}
static int clk_sam9x5_slow_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
void __iomem *sckcr = slowck->sckcr;
u32 tmp;
if (index > 1)
return -EINVAL;
tmp = readl(sckcr);
if ((!index && !(tmp & slowck->bits->cr_oscsel)) ||
(index && (tmp & slowck->bits->cr_oscsel)))
return 0;
if (index)
tmp |= slowck->bits->cr_oscsel;
else
tmp &= ~slowck->bits->cr_oscsel;
writel(tmp, sckcr);
if (system_state < SYSTEM_RUNNING)
udelay(SLOWCK_SW_TIME_USEC);
else
usleep_range(SLOWCK_SW_TIME_USEC, SLOWCK_SW_TIME_USEC + 1);
return 0;
}
static u8 clk_sam9x5_slow_get_parent(struct clk_hw *hw)
{
struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
return !!(readl(slowck->sckcr) & slowck->bits->cr_oscsel);
}
static const struct clk_ops sam9x5_slow_ops = {
.set_parent = clk_sam9x5_slow_set_parent,
.get_parent = clk_sam9x5_slow_get_parent,
};
static struct clk_hw * __init
at91_clk_register_sam9x5_slow(void __iomem *sckcr,
const char *name,
const char **parent_names,
int num_parents,
const struct clk_slow_bits *bits)
{
struct clk_sam9x5_slow *slowck;
struct clk_hw *hw;
struct clk_init_data init;
int ret;
if (!sckcr || !name || !parent_names || !num_parents)
return ERR_PTR(-EINVAL);
slowck = kzalloc(sizeof(*slowck), GFP_KERNEL);
if (!slowck)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &sam9x5_slow_ops;
init.parent_names = parent_names;
init.num_parents = num_parents;
init.flags = 0;
slowck->hw.init = &init;
slowck->sckcr = sckcr;
slowck->bits = bits;
slowck->parent = !!(readl(sckcr) & slowck->bits->cr_oscsel);
hw = &slowck->hw;
ret = clk_hw_register(NULL, &slowck->hw);
if (ret) {
kfree(slowck);
hw = ERR_PTR(ret);
}
return hw;
}
static void at91_clk_unregister_sam9x5_slow(struct clk_hw *hw)
{
struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
clk_hw_unregister(hw);
kfree(slowck);
}
static void __init at91sam9x5_sckc_register(struct device_node *np,
unsigned int rc_osc_startup_us,
const struct clk_slow_bits *bits)
{
const char *parent_names[2] = { "slow_rc_osc", "slow_osc" };
void __iomem *regbase = of_iomap(np, 0);
struct device_node *child = NULL;
const char *xtal_name;
struct clk_hw *slow_rc, *slow_osc, *slowck;
bool bypass;
int ret;
if (!regbase)
return;
slow_rc = at91_clk_register_slow_rc_osc(regbase, parent_names[0],
32768, 50000000,
rc_osc_startup_us, bits);
if (IS_ERR(slow_rc))
return;
xtal_name = of_clk_get_parent_name(np, 0);
if (!xtal_name) {
/* DT backward compatibility */
child = of_get_compatible_child(np, "atmel,at91sam9x5-clk-slow-osc");
if (!child)
goto unregister_slow_rc;
xtal_name = of_clk_get_parent_name(child, 0);
bypass = of_property_read_bool(child, "atmel,osc-bypass");
child = of_get_compatible_child(np, "atmel,at91sam9x5-clk-slow");
} else {
bypass = of_property_read_bool(np, "atmel,osc-bypass");
}
if (!xtal_name)
goto unregister_slow_rc;
slow_osc = at91_clk_register_slow_osc(regbase, parent_names[1],
xtal_name, 1200000, bypass, bits);
if (IS_ERR(slow_osc))
goto unregister_slow_rc;
slowck = at91_clk_register_sam9x5_slow(regbase, "slowck", parent_names,
2, bits);
if (IS_ERR(slowck))
goto unregister_slow_osc;
/* DT backward compatibility */
if (child)
ret = of_clk_add_hw_provider(child, of_clk_hw_simple_get,
slowck);
else
ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, slowck);
if (WARN_ON(ret))
goto unregister_slowck;
return;
unregister_slowck:
at91_clk_unregister_sam9x5_slow(slowck);
unregister_slow_osc:
at91_clk_unregister_slow_osc(slow_osc);
unregister_slow_rc:
at91_clk_unregister_slow_rc_osc(slow_rc);
}
static const struct clk_slow_bits at91sam9x5_bits = {
.cr_rcen = BIT(0),
.cr_osc32en = BIT(1),
.cr_osc32byp = BIT(2),
.cr_oscsel = BIT(3),
};
static void __init of_at91sam9x5_sckc_setup(struct device_node *np)
{
at91sam9x5_sckc_register(np, 75, &at91sam9x5_bits);
}
CLK_OF_DECLARE(at91sam9x5_clk_sckc, "atmel,at91sam9x5-sckc",
of_at91sam9x5_sckc_setup);
static void __init of_sama5d3_sckc_setup(struct device_node *np)
{
at91sam9x5_sckc_register(np, 500, &at91sam9x5_bits);
}
CLK_OF_DECLARE(sama5d3_clk_sckc, "atmel,sama5d3-sckc",
of_sama5d3_sckc_setup);
static const struct clk_slow_bits at91sam9x60_bits = {
.cr_osc32en = BIT(1),
.cr_osc32byp = BIT(2),
.cr_oscsel = BIT(24),
};
static void __init of_sam9x60_sckc_setup(struct device_node *np)
{
void __iomem *regbase = of_iomap(np, 0);
struct clk_hw_onecell_data *clk_data;
struct clk_hw *slow_rc, *slow_osc;
const char *xtal_name;
const char *parent_names[2] = { "slow_rc_osc", "slow_osc" };
bool bypass;
int ret;
if (!regbase)
return;
slow_rc = clk_hw_register_fixed_rate_with_accuracy(NULL, parent_names[0],
NULL, 0, 32768,
93750000);
if (IS_ERR(slow_rc))
return;
xtal_name = of_clk_get_parent_name(np, 0);
if (!xtal_name)
goto unregister_slow_rc;
bypass = of_property_read_bool(np, "atmel,osc-bypass");
slow_osc = at91_clk_register_slow_osc(regbase, parent_names[1],
xtal_name, 5000000, bypass,
&at91sam9x60_bits);
if (IS_ERR(slow_osc))
goto unregister_slow_rc;
clk_data = kzalloc(struct_size(clk_data, hws, 2), GFP_KERNEL);
if (!clk_data)
goto unregister_slow_osc;
/* MD_SLCK and TD_SLCK. */
clk_data->num = 2;
clk_data->hws[0] = clk_hw_register_fixed_rate(NULL, "md_slck",
parent_names[0],
0, 32768);
if (IS_ERR(clk_data->hws[0]))
goto clk_data_free;
clk_data->hws[1] = at91_clk_register_sam9x5_slow(regbase, "td_slck",
parent_names, 2,
&at91sam9x60_bits);
if (IS_ERR(clk_data->hws[1]))
goto unregister_md_slck;
ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_data);
if (WARN_ON(ret))
goto unregister_td_slck;
return;
unregister_td_slck:
at91_clk_unregister_sam9x5_slow(clk_data->hws[1]);
unregister_md_slck:
clk_hw_unregister(clk_data->hws[0]);
clk_data_free:
kfree(clk_data);
unregister_slow_osc:
at91_clk_unregister_slow_osc(slow_osc);
unregister_slow_rc:
clk_hw_unregister(slow_rc);
}
CLK_OF_DECLARE(sam9x60_clk_sckc, "microchip,sam9x60-sckc",
of_sam9x60_sckc_setup);
static int clk_sama5d4_slow_osc_prepare(struct clk_hw *hw)
{
struct clk_sama5d4_slow_osc *osc = to_clk_sama5d4_slow_osc(hw);
if (osc->prepared)
return 0;
/*
* Assume that if it has already been selected (for example by the
* bootloader), enough time has aready passed.
*/
if ((readl(osc->sckcr) & osc->bits->cr_oscsel)) {
osc->prepared = true;
return 0;
}
if (system_state < SYSTEM_RUNNING)
udelay(osc->startup_usec);
else
usleep_range(osc->startup_usec, osc->startup_usec + 1);
osc->prepared = true;
return 0;
}
static int clk_sama5d4_slow_osc_is_prepared(struct clk_hw *hw)
{
struct clk_sama5d4_slow_osc *osc = to_clk_sama5d4_slow_osc(hw);
return osc->prepared;
}
static const struct clk_ops sama5d4_slow_osc_ops = {
.prepare = clk_sama5d4_slow_osc_prepare,
.is_prepared = clk_sama5d4_slow_osc_is_prepared,
};
static const struct clk_slow_bits at91sama5d4_bits = {
.cr_oscsel = BIT(3),
};
static void __init of_sama5d4_sckc_setup(struct device_node *np)
{
void __iomem *regbase = of_iomap(np, 0);
struct clk_hw *slow_rc, *slowck;
struct clk_sama5d4_slow_osc *osc;
struct clk_init_data init;
const char *xtal_name;
const char *parent_names[2] = { "slow_rc_osc", "slow_osc" };
int ret;
if (!regbase)
return;
slow_rc = clk_hw_register_fixed_rate_with_accuracy(NULL,
parent_names[0],
NULL, 0, 32768,
250000000);
if (IS_ERR(slow_rc))
return;
xtal_name = of_clk_get_parent_name(np, 0);
osc = kzalloc(sizeof(*osc), GFP_KERNEL);
if (!osc)
goto unregister_slow_rc;
init.name = parent_names[1];
init.ops = &sama5d4_slow_osc_ops;
init.parent_names = &xtal_name;
init.num_parents = 1;
init.flags = CLK_IGNORE_UNUSED;
osc->hw.init = &init;
osc->sckcr = regbase;
osc->startup_usec = 1200000;
osc->bits = &at91sama5d4_bits;
ret = clk_hw_register(NULL, &osc->hw);
if (ret)
goto free_slow_osc_data;
slowck = at91_clk_register_sam9x5_slow(regbase, "slowck",
parent_names, 2,
&at91sama5d4_bits);
if (IS_ERR(slowck))
goto unregister_slow_osc;
ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, slowck);
if (WARN_ON(ret))
goto unregister_slowck;
return;
unregister_slowck:
at91_clk_unregister_sam9x5_slow(slowck);
unregister_slow_osc:
clk_hw_unregister(&osc->hw);
free_slow_osc_data:
kfree(osc);
unregister_slow_rc:
clk_hw_unregister(slow_rc);
}
CLK_OF_DECLARE(sama5d4_clk_sckc, "atmel,sama5d4-sckc",
of_sama5d4_sckc_setup);