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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
* JZ4740 SoC RTC driver
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeirq.h>
#include <linux/reboot.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#define JZ_REG_RTC_CTRL 0x00
#define JZ_REG_RTC_SEC 0x04
#define JZ_REG_RTC_SEC_ALARM 0x08
#define JZ_REG_RTC_REGULATOR 0x0C
#define JZ_REG_RTC_HIBERNATE 0x20
#define JZ_REG_RTC_WAKEUP_FILTER 0x24
#define JZ_REG_RTC_RESET_COUNTER 0x28
#define JZ_REG_RTC_SCRATCHPAD 0x34
/* The following are present on the jz4780 */
#define JZ_REG_RTC_WENR 0x3C
#define JZ_RTC_WENR_WEN BIT(31)
#define JZ_RTC_CTRL_WRDY BIT(7)
#define JZ_RTC_CTRL_1HZ BIT(6)
#define JZ_RTC_CTRL_1HZ_IRQ BIT(5)
#define JZ_RTC_CTRL_AF BIT(4)
#define JZ_RTC_CTRL_AF_IRQ BIT(3)
#define JZ_RTC_CTRL_AE BIT(2)
#define JZ_RTC_CTRL_ENABLE BIT(0)
/* Magic value to enable writes on jz4780 */
#define JZ_RTC_WENR_MAGIC 0xA55A
#define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0
#define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0
enum jz4740_rtc_type {
ID_JZ4740,
ID_JZ4760,
ID_JZ4780,
};
struct jz4740_rtc {
void __iomem *base;
enum jz4740_rtc_type type;
struct rtc_device *rtc;
struct clk *clk;
int irq;
spinlock_t lock;
unsigned int min_wakeup_pin_assert_time;
unsigned int reset_pin_assert_time;
};
static struct device *dev_for_power_off;
static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
{
return readl(rtc->base + reg);
}
static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
{
uint32_t ctrl;
int timeout = 10000;
do {
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
} while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);
return timeout ? 0 : -EIO;
}
static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc)
{
uint32_t ctrl;
int ret, timeout = 10000;
ret = jz4740_rtc_wait_write_ready(rtc);
if (ret != 0)
return ret;
writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR);
do {
ctrl = readl(rtc->base + JZ_REG_RTC_WENR);
} while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout);
return timeout ? 0 : -EIO;
}
static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
uint32_t val)
{
int ret = 0;
if (rtc->type >= ID_JZ4760)
ret = jz4780_rtc_enable_write(rtc);
if (ret == 0)
ret = jz4740_rtc_wait_write_ready(rtc);
if (ret == 0)
writel(val, rtc->base + reg);
return ret;
}
static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
bool set)
{
int ret;
unsigned long flags;
uint32_t ctrl;
spin_lock_irqsave(&rtc->lock, flags);
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
/* Don't clear interrupt flags by accident */
ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
if (set)
ctrl |= mask;
else
ctrl &= ~mask;
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
spin_unlock_irqrestore(&rtc->lock, flags);
return ret;
}
static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
uint32_t secs, secs2;
int timeout = 5;
if (jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD) != 0x12345678)
return -EINVAL;
/* If the seconds register is read while it is updated, it can contain a
* bogus value. This can be avoided by making sure that two consecutive
* reads have the same value.
*/
secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
while (secs != secs2 && --timeout) {
secs = secs2;
secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
}
if (timeout == 0)
return -EIO;
rtc_time64_to_tm(secs, time);
return 0;
}
static int jz4740_rtc_set_time(struct device *dev, struct rtc_time *time)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
int ret;
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, rtc_tm_to_time64(time));
if (ret)
return ret;
return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
}
static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
uint32_t secs;
uint32_t ctrl;
secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
rtc_time64_to_tm(secs, &alrm->time);
return 0;
}
static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
int ret;
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
uint32_t secs = lower_32_bits(rtc_tm_to_time64(&alrm->time));
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
if (!ret)
ret = jz4740_rtc_ctrl_set_bits(rtc,
JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled);
return ret;
}
static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
}
static const struct rtc_class_ops jz4740_rtc_ops = {
.read_time = jz4740_rtc_read_time,
.set_time = jz4740_rtc_set_time,
.read_alarm = jz4740_rtc_read_alarm,
.set_alarm = jz4740_rtc_set_alarm,
.alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
};
static irqreturn_t jz4740_rtc_irq(int irq, void *data)
{
struct jz4740_rtc *rtc = data;
uint32_t ctrl;
unsigned long events = 0;
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
if (ctrl & JZ_RTC_CTRL_1HZ)
events |= (RTC_UF | RTC_IRQF);
if (ctrl & JZ_RTC_CTRL_AF)
events |= (RTC_AF | RTC_IRQF);
rtc_update_irq(rtc->rtc, 1, events);
jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
return IRQ_HANDLED;
}
static void jz4740_rtc_poweroff(struct device *dev)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
}
static void jz4740_rtc_power_off(void)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev_for_power_off);
unsigned long rtc_rate;
unsigned long wakeup_filter_ticks;
unsigned long reset_counter_ticks;
clk_prepare_enable(rtc->clk);
rtc_rate = clk_get_rate(rtc->clk);
/*
* Set minimum wakeup pin assertion time: 100 ms.
* Range is 0 to 2 sec if RTC is clocked at 32 kHz.
*/
wakeup_filter_ticks =
(rtc->min_wakeup_pin_assert_time * rtc_rate) / 1000;
if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
else
wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
jz4740_rtc_reg_write(rtc,
JZ_REG_RTC_WAKEUP_FILTER, wakeup_filter_ticks);
/*
* Set reset pin low-level assertion time after wakeup: 60 ms.
* Range is 0 to 125 ms if RTC is clocked at 32 kHz.
*/
reset_counter_ticks = (rtc->reset_pin_assert_time * rtc_rate) / 1000;
if (reset_counter_ticks<
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