mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![Uwe Kleine-König](/assets/img/avatar_default.png)
The comment in the remove callback suggests that the driver is not supposed to be unbound. However returning an error code in the remove callback doesn't accomplish that. Instead set the suppress_bind_attrs property (which makes it impossible to unbind the driver via sysfs). The only remaining way to unbind a em_sti device would be module unloading, but that doesn't apply here, as the driver cannot be built as a module. Also drop the useless remove callback. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20230207193010.469495-1-u.kleine-koenig@pengutronix.de Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
366 lines
8.3 KiB
C
366 lines
8.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Emma Mobile Timer Support - STI
|
|
*
|
|
* Copyright (C) 2012 Magnus Damm
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/ioport.h>
|
|
#include <linux/io.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/err.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/clocksource.h>
|
|
#include <linux/clockchips.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/module.h>
|
|
|
|
enum { USER_CLOCKSOURCE, USER_CLOCKEVENT, USER_NR };
|
|
|
|
struct em_sti_priv {
|
|
void __iomem *base;
|
|
struct clk *clk;
|
|
struct platform_device *pdev;
|
|
unsigned int active[USER_NR];
|
|
unsigned long rate;
|
|
raw_spinlock_t lock;
|
|
struct clock_event_device ced;
|
|
struct clocksource cs;
|
|
};
|
|
|
|
#define STI_CONTROL 0x00
|
|
#define STI_COMPA_H 0x10
|
|
#define STI_COMPA_L 0x14
|
|
#define STI_COMPB_H 0x18
|
|
#define STI_COMPB_L 0x1c
|
|
#define STI_COUNT_H 0x20
|
|
#define STI_COUNT_L 0x24
|
|
#define STI_COUNT_RAW_H 0x28
|
|
#define STI_COUNT_RAW_L 0x2c
|
|
#define STI_SET_H 0x30
|
|
#define STI_SET_L 0x34
|
|
#define STI_INTSTATUS 0x40
|
|
#define STI_INTRAWSTATUS 0x44
|
|
#define STI_INTENSET 0x48
|
|
#define STI_INTENCLR 0x4c
|
|
#define STI_INTFFCLR 0x50
|
|
|
|
static inline unsigned long em_sti_read(struct em_sti_priv *p, int offs)
|
|
{
|
|
return ioread32(p->base + offs);
|
|
}
|
|
|
|
static inline void em_sti_write(struct em_sti_priv *p, int offs,
|
|
unsigned long value)
|
|
{
|
|
iowrite32(value, p->base + offs);
|
|
}
|
|
|
|
static int em_sti_enable(struct em_sti_priv *p)
|
|
{
|
|
int ret;
|
|
|
|
/* enable clock */
|
|
ret = clk_enable(p->clk);
|
|
if (ret) {
|
|
dev_err(&p->pdev->dev, "cannot enable clock\n");
|
|
return ret;
|
|
}
|
|
|
|
/* reset the counter */
|
|
em_sti_write(p, STI_SET_H, 0x40000000);
|
|
em_sti_write(p, STI_SET_L, 0x00000000);
|
|
|
|
/* mask and clear pending interrupts */
|
|
em_sti_write(p, STI_INTENCLR, 3);
|
|
em_sti_write(p, STI_INTFFCLR, 3);
|
|
|
|
/* enable updates of counter registers */
|
|
em_sti_write(p, STI_CONTROL, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void em_sti_disable(struct em_sti_priv *p)
|
|
{
|
|
/* mask interrupts */
|
|
em_sti_write(p, STI_INTENCLR, 3);
|
|
|
|
/* stop clock */
|
|
clk_disable(p->clk);
|
|
}
|
|
|
|
static u64 em_sti_count(struct em_sti_priv *p)
|
|
{
|
|
u64 ticks;
|
|
unsigned long flags;
|
|
|
|
/* the STI hardware buffers the 48-bit count, but to
|
|
* break it out into two 32-bit access the registers
|
|
* must be accessed in a certain order.
|
|
* Always read STI_COUNT_H before STI_COUNT_L.
|
|
*/
|
|
raw_spin_lock_irqsave(&p->lock, flags);
|
|
ticks = (u64)(em_sti_read(p, STI_COUNT_H) & 0xffff) << 32;
|
|
ticks |= em_sti_read(p, STI_COUNT_L);
|
|
raw_spin_unlock_irqrestore(&p->lock, flags);
|
|
|
|
return ticks;
|
|
}
|
|
|
|
static u64 em_sti_set_next(struct em_sti_priv *p, u64 next)
|
|
{
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&p->lock, flags);
|
|
|
|
/* mask compare A interrupt */
|
|
em_sti_write(p, STI_INTENCLR, 1);
|
|
|
|
/* update compare A value */
|
|
em_sti_write(p, STI_COMPA_H, next >> 32);
|
|
em_sti_write(p, STI_COMPA_L, next & 0xffffffff);
|
|
|
|
/* clear compare A interrupt source */
|
|
em_sti_write(p, STI_INTFFCLR, 1);
|
|
|
|
/* unmask compare A interrupt */
|
|
em_sti_write(p, STI_INTENSET, 1);
|
|
|
|
raw_spin_unlock_irqrestore(&p->lock, flags);
|
|
|
|
return next;
|
|
}
|
|
|
|
static irqreturn_t em_sti_interrupt(int irq, void *dev_id)
|
|
{
|
|
struct em_sti_priv *p = dev_id;
|
|
|
|
p->ced.event_handler(&p->ced);
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static int em_sti_start(struct em_sti_priv *p, unsigned int user)
|
|
{
|
|
unsigned long flags;
|
|
int used_before;
|
|
int ret = 0;
|
|
|
|
raw_spin_lock_irqsave(&p->lock, flags);
|
|
used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT];
|
|
if (!used_before)
|
|
ret = em_sti_enable(p);
|
|
|
|
if (!ret)
|
|
p->active[user] = 1;
|
|
raw_spin_unlock_irqrestore(&p->lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void em_sti_stop(struct em_sti_priv *p, unsigned int user)
|
|
{
|
|
unsigned long flags;
|
|
int used_before, used_after;
|
|
|
|
raw_spin_lock_irqsave(&p->lock, flags);
|
|
used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT];
|
|
p->active[user] = 0;
|
|
used_after = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT];
|
|
|
|
if (used_before && !used_after)
|
|
em_sti_disable(p);
|
|
raw_spin_unlock_irqrestore(&p->lock, flags);
|
|
}
|
|
|
|
static struct em_sti_priv *cs_to_em_sti(struct clocksource *cs)
|
|
{
|
|
return container_of(cs, struct em_sti_priv, cs);
|
|
}
|
|
|
|
static u64 em_sti_clocksource_read(struct clocksource *cs)
|
|
{
|
|
return em_sti_count(cs_to_em_sti(cs));
|
|
}
|
|
|
|
static int em_sti_clocksource_enable(struct clocksource *cs)
|
|
{
|
|
struct em_sti_priv *p = cs_to_em_sti(cs);
|
|
|
|
return em_sti_start(p, USER_CLOCKSOURCE);
|
|
}
|
|
|
|
static void em_sti_clocksource_disable(struct clocksource *cs)
|
|
{
|
|
em_sti_stop(cs_to_em_sti(cs), USER_CLOCKSOURCE);
|
|
}
|
|
|
|
static void em_sti_clocksource_resume(struct clocksource *cs)
|
|
{
|
|
em_sti_clocksource_enable(cs);
|
|
}
|
|
|
|
static int em_sti_register_clocksource(struct em_sti_priv *p)
|
|
{
|
|
struct clocksource *cs = &p->cs;
|
|
|
|
cs->name = dev_name(&p->pdev->dev);
|
|
cs->rating = 200;
|
|
cs->read = em_sti_clocksource_read;
|
|
cs->enable = em_sti_clocksource_enable;
|
|
cs->disable = em_sti_clocksource_disable;
|
|
cs->suspend = em_sti_clocksource_disable;
|
|
cs->resume = em_sti_clocksource_resume;
|
|
cs->mask = CLOCKSOURCE_MASK(48);
|
|
cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
|
|
|
|
dev_info(&p->pdev->dev, "used as clock source\n");
|
|
|
|
clocksource_register_hz(cs, p->rate);
|
|
return 0;
|
|
}
|
|
|
|
static struct em_sti_priv *ced_to_em_sti(struct clock_event_device *ced)
|
|
{
|
|
return container_of(ced, struct em_sti_priv, ced);
|
|
}
|
|
|
|
static int em_sti_clock_event_shutdown(struct clock_event_device *ced)
|
|
{
|
|
struct em_sti_priv *p = ced_to_em_sti(ced);
|
|
em_sti_stop(p, USER_CLOCKEVENT);
|
|
return 0;
|
|
}
|
|
|
|
static int em_sti_clock_event_set_oneshot(struct clock_event_device *ced)
|
|
{
|
|
struct em_sti_priv *p = ced_to_em_sti(ced);
|
|
|
|
dev_info(&p->pdev->dev, "used for oneshot clock events\n");
|
|
em_sti_start(p, USER_CLOCKEVENT);
|
|
return 0;
|
|
}
|
|
|
|
static int em_sti_clock_event_next(unsigned long delta,
|
|
struct clock_event_device *ced)
|
|
{
|
|
struct em_sti_priv *p = ced_to_em_sti(ced);
|
|
u64 next;
|
|
int safe;
|
|
|
|
next = em_sti_set_next(p, em_sti_count(p) + delta);
|
|
safe = em_sti_count(p) < (next - 1);
|
|
|
|
return !safe;
|
|
}
|
|
|
|
static void em_sti_register_clockevent(struct em_sti_priv *p)
|
|
{
|
|
struct clock_event_device *ced = &p->ced;
|
|
|
|
ced->name = dev_name(&p->pdev->dev);
|
|
ced->features = CLOCK_EVT_FEAT_ONESHOT;
|
|
ced->rating = 200;
|
|
ced->cpumask = cpu_possible_mask;
|
|
ced->set_next_event = em_sti_clock_event_next;
|
|
ced->set_state_shutdown = em_sti_clock_event_shutdown;
|
|
ced->set_state_oneshot = em_sti_clock_event_set_oneshot;
|
|
|
|
dev_info(&p->pdev->dev, "used for clock events\n");
|
|
|
|
clockevents_config_and_register(ced, p->rate, 2, 0xffffffff);
|
|
}
|
|
|
|
static int em_sti_probe(struct platform_device *pdev)
|
|
{
|
|
struct em_sti_priv *p;
|
|
int irq, ret;
|
|
|
|
p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
|
|
if (p == NULL)
|
|
return -ENOMEM;
|
|
|
|
p->pdev = pdev;
|
|
platform_set_drvdata(pdev, p);
|
|
|
|
irq = platform_get_irq(pdev, 0);
|
|
if (irq < 0)
|
|
return irq;
|
|
|
|
/* map memory, let base point to the STI instance */
|
|
p->base = devm_platform_ioremap_resource(pdev, 0);
|
|
if (IS_ERR(p->base))
|
|
return PTR_ERR(p->base);
|
|
|
|
ret = devm_request_irq(&pdev->dev, irq, em_sti_interrupt,
|
|
IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
|
|
dev_name(&pdev->dev), p);
|
|
if (ret) {
|
|
dev_err(&pdev->dev, "failed to request low IRQ\n");
|
|
return ret;
|
|
}
|
|
|
|
/* get hold of clock */
|
|
p->clk = devm_clk_get(&pdev->dev, "sclk");
|
|
if (IS_ERR(p->clk)) {
|
|
dev_err(&pdev->dev, "cannot get clock\n");
|
|
return PTR_ERR(p->clk);
|
|
}
|
|
|
|
ret = clk_prepare(p->clk);
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "cannot prepare clock\n");
|
|
return ret;
|
|
}
|
|
|
|
ret = clk_enable(p->clk);
|
|
if (ret < 0) {
|
|
dev_err(&p->pdev->dev, "cannot enable clock\n");
|
|
clk_unprepare(p->clk);
|
|
return ret;
|
|
}
|
|
p->rate = clk_get_rate(p->clk);
|
|
clk_disable(p->clk);
|
|
|
|
raw_spin_lock_init(&p->lock);
|
|
em_sti_register_clockevent(p);
|
|
em_sti_register_clocksource(p);
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id em_sti_dt_ids[] = {
|
|
{ .compatible = "renesas,em-sti", },
|
|
{},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, em_sti_dt_ids);
|
|
|
|
static struct platform_driver em_sti_device_driver = {
|
|
.probe = em_sti_probe,
|
|
.driver = {
|
|
.name = "em_sti",
|
|
.of_match_table = em_sti_dt_ids,
|
|
.suppress_bind_attrs = true,
|
|
}
|
|
};
|
|
|
|
static int __init em_sti_init(void)
|
|
{
|
|
return platform_driver_register(&em_sti_device_driver);
|
|
}
|
|
|
|
static void __exit em_sti_exit(void)
|
|
{
|
|
platform_driver_unregister(&em_sti_device_driver);
|
|
}
|
|
|
|
subsys_initcall(em_sti_init);
|
|
module_exit(em_sti_exit);
|
|
|
|
MODULE_AUTHOR("Magnus Damm");
|
|
MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver");
|
|
MODULE_LICENSE("GPL v2");
|