linux/drivers/clocksource/ingenic-ost.c
Maarten ter Huurne ca7b72b5a5 clocksource: Add driver for the Ingenic JZ47xx OST
OST is the OS Timer, a 64-bit timer/counter with buffered reading.

SoCs before the JZ4770 had (if any) a 32-bit OST; the JZ4770 and
JZ4780 have a 64-bit OST.

This driver will register both a clocksource and a sched_clock to the
system.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200212180408.30872-1-paul@crapouillou.net
2020-02-27 09:37:29 +01:00

190 lines
4.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* JZ47xx SoCs TCU Operating System Timer driver
*
* Copyright (C) 2016 Maarten ter Huurne <maarten@treewalker.org>
* Copyright (C) 2020 Paul Cercueil <paul@crapouillou.net>
*/
#include <linux/clk.h>
#include <linux/clocksource.h>
#include <linux/mfd/ingenic-tcu.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/regmap.h>
#include <linux/sched_clock.h>
#define TCU_OST_TCSR_MASK 0xffc0
#define TCU_OST_TCSR_CNT_MD BIT(15)
#define TCU_OST_CHANNEL 15
/*
* The TCU_REG_OST_CNT{L,R} from <linux/mfd/ingenic-tcu.h> are only for the
* regmap; these are for use with the __iomem pointer.
*/
#define OST_REG_CNTL 0x4
#define OST_REG_CNTH 0x8
struct ingenic_ost_soc_info {
bool is64bit;
};
struct ingenic_ost {
void __iomem *regs;
struct clk *clk;
struct clocksource cs;
};
static struct ingenic_ost *ingenic_ost;
static u64 notrace ingenic_ost_read_cntl(void)
{
/* Read using __iomem pointer instead of regmap to avoid locking */
return readl(ingenic_ost->regs + OST_REG_CNTL);
}
static u64 notrace ingenic_ost_read_cnth(void)
{
/* Read using __iomem pointer instead of regmap to avoid locking */
return readl(ingenic_ost->regs + OST_REG_CNTH);
}
static u64 notrace ingenic_ost_clocksource_readl(struct clocksource *cs)
{
return ingenic_ost_read_cntl();
}
static u64 notrace ingenic_ost_clocksource_readh(struct clocksource *cs)
{
return ingenic_ost_read_cnth();
}
static int __init ingenic_ost_probe(struct platform_device *pdev)
{
const struct ingenic_ost_soc_info *soc_info;
struct device *dev = &pdev->dev;
struct ingenic_ost *ost;
struct clocksource *cs;
struct regmap *map;
unsigned long rate;
int err;
soc_info = device_get_match_data(dev);
if (!soc_info)
return -EINVAL;
ost = devm_kzalloc(dev, sizeof(*ost), GFP_KERNEL);
if (!ost)
return -ENOMEM;
ingenic_ost = ost;
ost->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(ost->regs))
return PTR_ERR(ost->regs);
map = device_node_to_regmap(dev->parent->of_node);
if (!map) {
dev_err(dev, "regmap not found");
return -EINVAL;
}
ost->clk = devm_clk_get(dev, "ost");
if (IS_ERR(ost->clk))
return PTR_ERR(ost->clk);
err = clk_prepare_enable(ost->clk);
if (err)
return err;
/* Clear counter high/low registers */
if (soc_info->is64bit)
regmap_write(map, TCU_REG_OST_CNTL, 0);
regmap_write(map, TCU_REG_OST_CNTH, 0);
/* Don't reset counter at compare value. */
regmap_update_bits(map, TCU_REG_OST_TCSR,
TCU_OST_TCSR_MASK, TCU_OST_TCSR_CNT_MD);
rate = clk_get_rate(ost->clk);
/* Enable OST TCU channel */
regmap_write(map, TCU_REG_TESR, BIT(TCU_OST_CHANNEL));
cs = &ost->cs;
cs->name = "ingenic-ost";
cs->rating = 320;
cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
cs->mask = CLOCKSOURCE_MASK(32);
if (soc_info->is64bit)
cs->read = ingenic_ost_clocksource_readl;
else
cs->read = ingenic_ost_clocksource_readh;
err = clocksource_register_hz(cs, rate);
if (err) {
dev_err(dev, "clocksource registration failed");
clk_disable_unprepare(ost->clk);
return err;
}
if (soc_info->is64bit)
sched_clock_register(ingenic_ost_read_cntl, 32, rate);
else
sched_clock_register(ingenic_ost_read_cnth, 32, rate);
return 0;
}
static int __maybe_unused ingenic_ost_suspend(struct device *dev)
{
struct ingenic_ost *ost = dev_get_drvdata(dev);
clk_disable(ost->clk);
return 0;
}
static int __maybe_unused ingenic_ost_resume(struct device *dev)
{
struct ingenic_ost *ost = dev_get_drvdata(dev);
return clk_enable(ost->clk);
}
static const struct dev_pm_ops __maybe_unused ingenic_ost_pm_ops = {
/* _noirq: We want the OST clock to be gated last / ungated first */
.suspend_noirq = ingenic_ost_suspend,
.resume_noirq = ingenic_ost_resume,
};
static const struct ingenic_ost_soc_info jz4725b_ost_soc_info = {
.is64bit = false,
};
static const struct ingenic_ost_soc_info jz4770_ost_soc_info = {
.is64bit = true,
};
static const struct of_device_id ingenic_ost_of_match[] = {
{ .compatible = "ingenic,jz4725b-ost", .data = &jz4725b_ost_soc_info, },
{ .compatible = "ingenic,jz4770-ost", .data = &jz4770_ost_soc_info, },
{ }
};
static struct platform_driver ingenic_ost_driver = {
.driver = {
.name = "ingenic-ost",
#ifdef CONFIG_PM_SUSPEND
.pm = &ingenic_ost_pm_ops,
#endif
.of_match_table = ingenic_ost_of_match,
},
};
builtin_platform_driver_probe(ingenic_ost_driver, ingenic_ost_probe);