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linux/drivers/rtc/rtc-jz4740.c
Mathieu Malaterre 695e38d881 rtc: jz4740: fix loading of rtc driver 
The current timeout for waiting for WRDY is not always sufficient. Always
increase it to 10000 even on JZ4740. This is technically only required on
JZ4780, where the current symptoms seen after a hard reboot are:

  jz4740-rtc 10003000.rtc: rtc core: registered 10003000.rtc as rtc0
  jz4740-rtc 10003000.rtc: Could not write to RTC registers
  jz4740-rtc: probe of 10003000.rtc failed with error -5

Suggested-by: Alex Smith <alex.smith@imgtec.com>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2017-10-12 14:28:14 +02:00

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/*
* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
* JZ4740 SoC RTC driver
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#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/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_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_JZ4780)
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 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_time_to_tm(secs, time);
return rtc_valid_tm(time);
}
static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs);
}
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_time_to_tm(secs, &alrm->time);
return rtc_valid_tm(&alrm->time);
}
static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
int ret;
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
unsigned long secs;
rtc_tm_to_time(&alrm->time, &secs);
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_mmss = jz4740_rtc_set_mmss,
.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 < JZ_RTC_RESET_COUNTER_MASK)
reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK;
else
reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK;
jz4740_rtc_reg_write(rtc,
JZ_REG_RTC_RESET_COUNTER, reset_counter_ticks);
jz4740_rtc_poweroff(dev_for_power_off);
kernel_halt();
}
static const struct of_device_id jz4740_rtc_of_match[] = {
{ .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
{ .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
{},
};
MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match);
static int jz4740_rtc_probe(struct platform_device *pdev)
{
int ret;
struct jz4740_rtc *rtc;
uint32_t scratchpad;
struct resource *mem;
const struct platform_device_id *id = platform_get_device_id(pdev);
const struct of_device_id *of_id = of_match_device(
jz4740_rtc_of_match, &pdev->dev);
struct device_node *np = pdev->dev.of_node;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
if (of_id)
rtc->type = (enum jz4740_rtc_type)of_id->data;
else
rtc->type = id->driver_data;
rtc->irq = platform_get_irq(pdev, 0);
if (rtc->irq < 0) {
dev_err(&pdev->dev, "Failed to get platform irq\n");
return -ENOENT;
}
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rtc->base = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(rtc->base))
return PTR_ERR(rtc->base);
rtc->clk = devm_clk_get(&pdev->dev, "rtc");
if (IS_ERR(rtc->clk)) {
dev_err(&pdev->dev, "Failed to get RTC clock\n");
return PTR_ERR(rtc->clk);
}
spin_lock_init(&rtc->lock);
platform_set_drvdata(pdev, rtc);
device_init_wakeup(&pdev->dev, 1);
rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&jz4740_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc)) {
ret = PTR_ERR(rtc->rtc);
dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret);
return ret;
}
ret = devm_request_irq(&pdev->dev, rtc->irq, jz4740_rtc_irq, 0,
pdev->name, rtc);
if (ret) {
dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret);
return ret;
}
scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD);
if (scratchpad != 0x12345678) {
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0);
if (ret) {
dev_err(&pdev->dev, "Could not write to RTC registers\n");
return ret;
}
}
if (np && of_device_is_system_power_controller(np)) {
if (!pm_power_off) {
/* Default: 60ms */
rtc->reset_pin_assert_time = 60;
of_property_read_u32(np, "reset-pin-assert-time-ms",
&rtc->reset_pin_assert_time);
/* Default: 100ms */
rtc->min_wakeup_pin_assert_time = 100;
of_property_read_u32(np,
"min-wakeup-pin-assert-time-ms",
&rtc->min_wakeup_pin_assert_time);
dev_for_power_off = &pdev->dev;
pm_power_off = jz4740_rtc_power_off;
} else {
dev_warn(&pdev->dev,
"Poweroff handler already present!\n");
}
}
return 0;
}
#ifdef CONFIG_PM
static int jz4740_rtc_suspend(struct device *dev)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(rtc->irq);
return 0;
}
static int jz4740_rtc_resume(struct device *dev)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(rtc->irq);
return 0;
}
static const struct dev_pm_ops jz4740_pm_ops = {
.suspend = jz4740_rtc_suspend,
.resume = jz4740_rtc_resume,
};
#define JZ4740_RTC_PM_OPS (&jz4740_pm_ops)
#else
#define JZ4740_RTC_PM_OPS NULL
#endif /* CONFIG_PM */
static const struct platform_device_id jz4740_rtc_ids[] = {
{ "jz4740-rtc", ID_JZ4740 },
{ "jz4780-rtc", ID_JZ4780 },
{}
};
MODULE_DEVICE_TABLE(platform, jz4740_rtc_ids);
static struct platform_driver jz4740_rtc_driver = {
.probe = jz4740_rtc_probe,
.driver = {
.name = "jz4740-rtc",
.pm = JZ4740_RTC_PM_OPS,
.of_match_table = of_match_ptr(jz4740_rtc_of_match),
},
.id_table = jz4740_rtc_ids,
};
module_platform_driver(jz4740_rtc_driver);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
MODULE_ALIAS("platform:jz4740-rtc");
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