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linux/drivers/rtc/rtc-stk17ta8.c
Uwe Kleine-König 81e627e00a move stk17ta8's probe function to .devinit.text 
A pointer to stk17ta8_rtc_probe is passed to the core via
platform_driver_register and so the function must not disappear when the
.init sections are discarded.  Otherwise (if also having HOTPLUG=y)
unbinding and binding a device to the driver via sysfs will result in an
oops as does a device being registered late.

An alternative to this patch is using platform_driver_probe instead of
platform_driver_register plus removing the pointer to the probe function
from the struct platform_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hannes Eder <hannes@hanneseder.net>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-11-09 09:40:58 +01:00

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/*
* A RTC driver for the Simtek STK17TA8
*
* By Thomas Hommel <thomas.hommel@gefanuc.com>
*
* Based on the DS1553 driver from
* Atsushi Nemoto <anemo@mba.ocn.ne.jp>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#define DRV_VERSION "0.1"
#define RTC_REG_SIZE 0x20000
#define RTC_OFFSET 0x1fff0
#define RTC_FLAGS (RTC_OFFSET + 0)
#define RTC_CENTURY (RTC_OFFSET + 1)
#define RTC_SECONDS_ALARM (RTC_OFFSET + 2)
#define RTC_MINUTES_ALARM (RTC_OFFSET + 3)
#define RTC_HOURS_ALARM (RTC_OFFSET + 4)
#define RTC_DATE_ALARM (RTC_OFFSET + 5)
#define RTC_INTERRUPTS (RTC_OFFSET + 6)
#define RTC_WATCHDOG (RTC_OFFSET + 7)
#define RTC_CALIBRATION (RTC_OFFSET + 8)
#define RTC_SECONDS (RTC_OFFSET + 9)
#define RTC_MINUTES (RTC_OFFSET + 10)
#define RTC_HOURS (RTC_OFFSET + 11)
#define RTC_DAY (RTC_OFFSET + 12)
#define RTC_DATE (RTC_OFFSET + 13)
#define RTC_MONTH (RTC_OFFSET + 14)
#define RTC_YEAR (RTC_OFFSET + 15)
#define RTC_SECONDS_MASK 0x7f
#define RTC_DAY_MASK 0x07
#define RTC_CAL_MASK 0x3f
/* Bits in the Calibration register */
#define RTC_STOP 0x80
/* Bits in the Flags register */
#define RTC_FLAGS_AF 0x40
#define RTC_FLAGS_PF 0x20
#define RTC_WRITE 0x02
#define RTC_READ 0x01
/* Bits in the Interrupts register */
#define RTC_INTS_AIE 0x40
struct rtc_plat_data {
struct rtc_device *rtc;
void __iomem *ioaddr;
unsigned long baseaddr;
unsigned long last_jiffies;
int irq;
unsigned int irqen;
int alrm_sec;
int alrm_min;
int alrm_hour;
int alrm_mday;
};
static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
u8 flags;
flags = readb(pdata->ioaddr + RTC_FLAGS);
writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
return 0;
}
static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
unsigned int year, month, day, hour, minute, second, week;
unsigned int century;
u8 flags;
/* give enough time to update RTC in case of continuous read */
if (pdata->last_jiffies == jiffies)
msleep(1);
pdata->last_jiffies = jiffies;
flags = readb(pdata->ioaddr + RTC_FLAGS);
writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
minute = readb(ioaddr + RTC_MINUTES);
hour = readb(ioaddr + RTC_HOURS);
day = readb(ioaddr + RTC_DATE);
week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
month = readb(ioaddr + RTC_MONTH);
year = readb(ioaddr + RTC_YEAR);
century = readb(ioaddr + RTC_CENTURY);
writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
tm->tm_sec = bcd2bin(second);
tm->tm_min = bcd2bin(minute);
tm->tm_hour = bcd2bin(hour);
tm->tm_mday = bcd2bin(day);
tm->tm_wday = bcd2bin(week);
tm->tm_mon = bcd2bin(month) - 1;
/* year is 1900 + tm->tm_year */
tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
if (rtc_valid_tm(tm) < 0) {
dev_err(dev, "retrieved date/time is not valid.\n");
rtc_time_to_tm(0, tm);
}
return 0;
}
static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
{
void __iomem *ioaddr = pdata->ioaddr;
unsigned long irqflags;
u8 flags;
spin_lock_irqsave(&pdata->rtc->irq_lock, irqflags);
flags = readb(ioaddr + RTC_FLAGS);
writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_mday),
ioaddr + RTC_DATE_ALARM);
writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_hour),
ioaddr + RTC_HOURS_ALARM);
writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_min),
ioaddr + RTC_MINUTES_ALARM);
writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_sec),
ioaddr + RTC_SECONDS_ALARM);
writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
readb(ioaddr + RTC_FLAGS); /* clear interrupts */
writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
spin_unlock_irqrestore(&pdata->rtc->irq_lock, irqflags);
}
static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
pdata->alrm_mday = alrm->time.tm_mday;
pdata->alrm_hour = alrm->time.tm_hour;
pdata->alrm_min = alrm->time.tm_min;
pdata->alrm_sec = alrm->time.tm_sec;
if (alrm->enabled)
pdata->irqen |= RTC_AF;
stk17ta8_rtc_update_alarm(pdata);
return 0;
}
static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
return 0;
}
static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = dev_id;
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
unsigned long events = RTC_IRQF;
/* read and clear interrupt */
if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
return IRQ_NONE;
if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
events |= RTC_UF;
else
events |= RTC_AF;
rtc_update_irq(pdata->rtc, 1, events);
return IRQ_HANDLED;
}
static int stk17ta8_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
switch (cmd) {
case RTC_AIE_OFF:
pdata->irqen &= ~RTC_AF;
stk17ta8_rtc_update_alarm(pdata);
break;
case RTC_AIE_ON:
pdata->irqen |= RTC_AF;
stk17ta8_rtc_update_alarm(pdata);
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static const struct rtc_class_ops stk17ta8_rtc_ops = {
.read_time = stk17ta8_rtc_read_time,
.set_time = stk17ta8_rtc_set_time,
.read_alarm = stk17ta8_rtc_read_alarm,
.set_alarm = stk17ta8_rtc_set_alarm,
.ioctl = stk17ta8_rtc_ioctl,
};
static ssize_t stk17ta8_nvram_read(struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t pos, size_t size)
{
struct platform_device *pdev =
to_platform_device(container_of(kobj, struct device, kobj));
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
ssize_t count;
for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
*buf++ = readb(ioaddr + pos++);
return count;
}
static ssize_t stk17ta8_nvram_write(struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t pos, size_t size)
{
struct platform_device *pdev =
to_platform_device(container_of(kobj, struct device, kobj));
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
ssize_t count;
for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
writeb(*buf++, ioaddr + pos++);
return count;
}
static struct bin_attribute stk17ta8_nvram_attr = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.size = RTC_OFFSET,
.read = stk17ta8_nvram_read,
.write = stk17ta8_nvram_write,
};
static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
struct resource *res;
unsigned int cal;
unsigned int flags;
struct rtc_plat_data *pdata;
void __iomem *ioaddr = NULL;
int ret = 0;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
ret = -EBUSY;
goto out;
}
pdata->baseaddr = res->start;
ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
if (!ioaddr) {
ret = -ENOMEM;
goto out;
}
pdata->ioaddr = ioaddr;
pdata->irq = platform_get_irq(pdev, 0);
/* turn RTC on if it was not on */
cal = readb(ioaddr + RTC_CALIBRATION);
if (cal & RTC_STOP) {
cal &= RTC_CAL_MASK;
flags = readb(ioaddr + RTC_FLAGS);
writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
writeb(cal, ioaddr + RTC_CALIBRATION);
writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
}
if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
dev_warn(&pdev->dev, "voltage-low detected.\n");
if (pdata->irq > 0) {
writeb(0, ioaddr + RTC_INTERRUPTS);
if (request_irq(pdata->irq, stk17ta8_rtc_interrupt,
IRQF_DISABLED | IRQF_SHARED,
pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
pdata->irq = 0;
}
}
rtc = rtc_device_register(pdev->name, &pdev->dev,
&stk17ta8_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
ret = PTR_ERR(rtc);
goto out;
}
pdata->rtc = rtc;
pdata->last_jiffies = jiffies;
platform_set_drvdata(pdev, pdata);
ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
if (ret)
goto out;
return 0;
out:
if (pdata->rtc)
rtc_device_unregister(pdata->rtc);
if (pdata->irq > 0)
free_irq(pdata->irq, pdev);
if (ioaddr)
iounmap(ioaddr);
if (pdata->baseaddr)
release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
kfree(pdata);
return ret;
}
static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev)
{
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
rtc_device_unregister(pdata->rtc);
if (pdata->irq > 0) {
writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
free_irq(pdata->irq, pdev);
}
iounmap(pdata->ioaddr);
release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
kfree(pdata);
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:stk17ta8");
static struct platform_driver stk17ta8_rtc_driver = {
.probe = stk17ta8_rtc_probe,
.remove = __devexit_p(stk17ta8_rtc_remove),
.driver = {
.name = "stk17ta8",
.owner = THIS_MODULE,
},
};
static __init int stk17ta8_init(void)
{
return platform_driver_register(&stk17ta8_rtc_driver);
}
static __exit void stk17ta8_exit(void)
{
platform_driver_unregister(&stk17ta8_rtc_driver);
}
module_init(stk17ta8_init);
module_exit(stk17ta8_exit);
MODULE_AUTHOR("Thomas Hommel <thomas.hommel@gefanuc.com>");
MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
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