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linux/drivers/rtc/rtc-spear.c
Lars-Peter Clausen a16e8393ac drivers/rtc/rtc-spear.c: fix several error checks 
There are several comparisons of a unsigned int to less than zero int
spear RTC driver.  Such a check will always be true.  In all these cases a
signed int is assigned to the unsigned variable, which is checked, before.
 So the right fix is to make the checked variable signed as well.  In one
case the check can be dropped completely, because all it does it returns
'err' if 'err' is less than zero, otherwise it returns 0.  Since in this
particular case 'err' is always either 0 or less this is the same as just
returning 'err'.

The issue has been found using the following coccinelle semantic patch:

//<smpl>
@@
type T;
unsigned T i;
@@
(
*i < 0
|
*i >= 0
)
//</smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Viresh Kumar <viresh.kumar@st.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06 03:05:03 +09:00

547 lines
14 KiB
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/*
* drivers/rtc/rtc-spear.c
*
* Copyright (C) 2010 ST Microelectronics
* Rajeev Kumar<rajeev-dlh.kumar@st.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/bcd.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
/* RTC registers */
#define TIME_REG 0x00
#define DATE_REG 0x04
#define ALARM_TIME_REG 0x08
#define ALARM_DATE_REG 0x0C
#define CTRL_REG 0x10
#define STATUS_REG 0x14
/* TIME_REG & ALARM_TIME_REG */
#define SECONDS_UNITS (0xf<<0) /* seconds units position */
#define SECONDS_TENS (0x7<<4) /* seconds tens position */
#define MINUTES_UNITS (0xf<<8) /* minutes units position */
#define MINUTES_TENS (0x7<<12) /* minutes tens position */
#define HOURS_UNITS (0xf<<16) /* hours units position */
#define HOURS_TENS (0x3<<20) /* hours tens position */
/* DATE_REG & ALARM_DATE_REG */
#define DAYS_UNITS (0xf<<0) /* days units position */
#define DAYS_TENS (0x3<<4) /* days tens position */
#define MONTHS_UNITS (0xf<<8) /* months units position */
#define MONTHS_TENS (0x1<<12) /* months tens position */
#define YEARS_UNITS (0xf<<16) /* years units position */
#define YEARS_TENS (0xf<<20) /* years tens position */
#define YEARS_HUNDREDS (0xf<<24) /* years hundereds position */
#define YEARS_MILLENIUMS (0xf<<28) /* years millenium position */
/* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
#define SECOND_SHIFT 0x00 /* seconds units */
#define MINUTE_SHIFT 0x08 /* minutes units position */
#define HOUR_SHIFT 0x10 /* hours units position */
#define MDAY_SHIFT 0x00 /* Month day shift */
#define MONTH_SHIFT 0x08 /* Month shift */
#define YEAR_SHIFT 0x10 /* Year shift */
#define SECOND_MASK 0x7F
#define MIN_MASK 0x7F
#define HOUR_MASK 0x3F
#define DAY_MASK 0x3F
#define MONTH_MASK 0x7F
#define YEAR_MASK 0xFFFF
/* date reg equal to time reg, for debug only */
#define TIME_BYP (1<<9)
#define INT_ENABLE (1<<31) /* interrupt enable */
/* STATUS_REG */
#define CLK_UNCONNECTED (1<<0)
#define PEND_WR_TIME (1<<2)
#define PEND_WR_DATE (1<<3)
#define LOST_WR_TIME (1<<4)
#define LOST_WR_DATE (1<<5)
#define RTC_INT_MASK (1<<31)
#define STATUS_BUSY (PEND_WR_TIME | PEND_WR_DATE)
#define STATUS_FAIL (LOST_WR_TIME | LOST_WR_DATE)
struct spear_rtc_config {
struct rtc_device *rtc;
struct clk *clk;
spinlock_t lock;
void __iomem *ioaddr;
unsigned int irq_wake;
};
static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
{
unsigned int val;
unsigned long flags;
spin_lock_irqsave(&config->lock, flags);
val = readl(config->ioaddr + STATUS_REG);
val |= RTC_INT_MASK;
writel(val, config->ioaddr + STATUS_REG);
spin_unlock_irqrestore(&config->lock, flags);
}
static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
{
unsigned int val;
val = readl(config->ioaddr + CTRL_REG);
if (!(val & INT_ENABLE)) {
spear_rtc_clear_interrupt(config);
val |= INT_ENABLE;
writel(val, config->ioaddr + CTRL_REG);
}
}
static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
{
unsigned int val;
val = readl(config->ioaddr + CTRL_REG);
if (val & INT_ENABLE) {
val &= ~INT_ENABLE;
writel(val, config->ioaddr + CTRL_REG);
}
}
static inline int is_write_complete(struct spear_rtc_config *config)
{
int ret = 0;
unsigned long flags;
spin_lock_irqsave(&config->lock, flags);
if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
ret = -EIO;
spin_unlock_irqrestore(&config->lock, flags);
return ret;
}
static void rtc_wait_not_busy(struct spear_rtc_config *config)
{
int status, count = 0;
unsigned long flags;
/* Assuming BUSY may stay active for 80 msec) */
for (count = 0; count < 80; count++) {
spin_lock_irqsave(&config->lock, flags);
status = readl(config->ioaddr + STATUS_REG);
spin_unlock_irqrestore(&config->lock, flags);
if ((status & STATUS_BUSY) == 0)
break;
/* check status busy, after each msec */
msleep(1);
}
}
static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
{
struct spear_rtc_config *config = dev_id;
unsigned long flags, events = 0;
unsigned int irq_data;
spin_lock_irqsave(&config->lock, flags);
irq_data = readl(config->ioaddr + STATUS_REG);
spin_unlock_irqrestore(&config->lock, flags);
if ((irq_data & RTC_INT_MASK)) {
spear_rtc_clear_interrupt(config);
events = RTC_IRQF | RTC_AF;
rtc_update_irq(config->rtc, 1, events);
return IRQ_HANDLED;
} else
return IRQ_NONE;
}
static int tm2bcd(struct rtc_time *tm)
{
if (rtc_valid_tm(tm) != 0)
return -EINVAL;
tm->tm_sec = bin2bcd(tm->tm_sec);
tm->tm_min = bin2bcd(tm->tm_min);
tm->tm_hour = bin2bcd(tm->tm_hour);
tm->tm_mday = bin2bcd(tm->tm_mday);
tm->tm_mon = bin2bcd(tm->tm_mon + 1);
tm->tm_year = bin2bcd(tm->tm_year);
return 0;
}
static void bcd2tm(struct rtc_time *tm)
{
tm->tm_sec = bcd2bin(tm->tm_sec);
tm->tm_min = bcd2bin(tm->tm_min);
tm->tm_hour = bcd2bin(tm->tm_hour);
tm->tm_mday = bcd2bin(tm->tm_mday);
tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
/* epoch == 1900 */
tm->tm_year = bcd2bin(tm->tm_year);
}
/*
* spear_rtc_read_time - set the time
* @dev: rtc device in use
* @tm: holds date and time
*
* This function read time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
/* we don't report wday/yday/isdst ... */
rtc_wait_not_busy(config);
time = readl(config->ioaddr + TIME_REG);
date = readl(config->ioaddr + DATE_REG);
tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
bcd2tm(tm);
return 0;
}
/*
* spear_rtc_set_time - set the time
* @dev: rtc device in use
* @tm: holds date and time
*
* This function set time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
if (tm2bcd(tm) < 0)
return -EINVAL;
rtc_wait_not_busy(config);
time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
(tm->tm_hour << HOUR_SHIFT);
date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
(tm->tm_year << YEAR_SHIFT);
writel(time, config->ioaddr + TIME_REG);
writel(date, config->ioaddr + DATE_REG);
return is_write_complete(config);
}
/*
* spear_rtc_read_alarm - read the alarm time
* @dev: rtc device in use
* @alm: holds alarm date and time
*
* This function read alarm time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
rtc_wait_not_busy(config);
time = readl(config->ioaddr + ALARM_TIME_REG);
date = readl(config->ioaddr + ALARM_DATE_REG);
alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
bcd2tm(&alm->time);
alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
return 0;
}
/*
* spear_rtc_set_alarm - set the alarm time
* @dev: rtc device in use
* @alm: holds alarm date and time
*
* This function set alarm time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
int err;
if (tm2bcd(&alm->time) < 0)
return -EINVAL;
rtc_wait_not_busy(config);
time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);
date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
writel(time, config->ioaddr + ALARM_TIME_REG);
writel(date, config->ioaddr + ALARM_DATE_REG);
err = is_write_complete(config);
if (err < 0)
return err;
if (alm->enabled)
spear_rtc_enable_interrupt(config);
else
spear_rtc_disable_interrupt(config);
return 0;
}
static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
int ret = 0;
spear_rtc_clear_interrupt(config);
switch (enabled) {
case 0:
/* alarm off */
spear_rtc_disable_interrupt(config);
break;
case 1:
/* alarm on */
spear_rtc_enable_interrupt(config);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static struct rtc_class_ops spear_rtc_ops = {
.read_time = spear_rtc_read_time,
.set_time = spear_rtc_set_time,
.read_alarm = spear_rtc_read_alarm,
.set_alarm = spear_rtc_set_alarm,
.alarm_irq_enable = spear_alarm_irq_enable,
};
static int __devinit spear_rtc_probe(struct platform_device *pdev)
{
struct resource *res;
struct spear_rtc_config *config;
int status = 0;
int irq;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "no resource defined\n");
return -EBUSY;
}
if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
dev_err(&pdev->dev, "rtc region already claimed\n");
return -EBUSY;
}
config = kzalloc(sizeof(*config), GFP_KERNEL);
if (!config) {
dev_err(&pdev->dev, "out of memory\n");
status = -ENOMEM;
goto err_release_region;
}
config->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(config->clk)) {
status = PTR_ERR(config->clk);
goto err_kfree;
}
status = clk_enable(config->clk);
if (status < 0)
goto err_clk_put;
config->ioaddr = ioremap(res->start, resource_size(res));
if (!config->ioaddr) {
dev_err(&pdev->dev, "ioremap fail\n");
status = -ENOMEM;
goto err_disable_clock;
}
spin_lock_init(&config->lock);
platform_set_drvdata(pdev, config);
config->rtc = rtc_device_register(pdev->name, &pdev->dev,
&spear_rtc_ops, THIS_MODULE);
if (IS_ERR(config->rtc)) {
dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
PTR_ERR(config->rtc));
status = PTR_ERR(config->rtc);
goto err_iounmap;
}
/* alarm irqs */
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "no update irq?\n");
status = irq;
goto err_clear_platdata;
}
status = request_irq(irq, spear_rtc_irq, 0, pdev->name, config);
if (status) {
dev_err(&pdev->dev, "Alarm interrupt IRQ%d already \
claimed\n", irq);
goto err_clear_platdata;
}
if (!device_can_wakeup(&pdev->dev))
device_init_wakeup(&pdev->dev, 1);
return 0;
err_clear_platdata:
platform_set_drvdata(pdev, NULL);
rtc_device_unregister(config->rtc);
err_iounmap:
iounmap(config->ioaddr);
err_disable_clock:
clk_disable(config->clk);
err_clk_put:
clk_put(config->clk);
err_kfree:
kfree(config);
err_release_region:
release_mem_region(res->start, resource_size(res));
return status;
}
static int __devexit spear_rtc_remove(struct platform_device *pdev)
{
struct spear_rtc_config *config = platform_get_drvdata(pdev);
int irq;
struct resource *res;
/* leave rtc running, but disable irqs */
spear_rtc_disable_interrupt(config);
device_init_wakeup(&pdev->dev, 0);
irq = platform_get_irq(pdev, 0);
if (irq)
free_irq(irq, pdev);
clk_disable(config->clk);
clk_put(config->clk);
iounmap(config->ioaddr);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res)
release_mem_region(res->start, resource_size(res));
platform_set_drvdata(pdev, NULL);
rtc_device_unregister(config->rtc);
kfree(config);
return 0;
}
#ifdef CONFIG_PM
static int spear_rtc_suspend(struct platform_device *pdev, pm_message_t state)
{
struct spear_rtc_config *config = platform_get_drvdata(pdev);
int irq;
irq = platform_get_irq(pdev, 0);
if (device_may_wakeup(&pdev->dev)) {
if (!enable_irq_wake(irq))
config->irq_wake = 1;
} else {
spear_rtc_disable_interrupt(config);
clk_disable(config->clk);
}
return 0;
}
static int spear_rtc_resume(struct platform_device *pdev)
{
struct spear_rtc_config *config = platform_get_drvdata(pdev);
int irq;
irq = platform_get_irq(pdev, 0);
if (device_may_wakeup(&pdev->dev)) {
if (config->irq_wake) {
disable_irq_wake(irq);
config->irq_wake = 0;
}
} else {
clk_enable(config->clk);
spear_rtc_enable_interrupt(config);
}
return 0;
}
#else
#define spear_rtc_suspend NULL
#define spear_rtc_resume NULL
#endif
static void spear_rtc_shutdown(struct platform_device *pdev)
{
struct spear_rtc_config *config = platform_get_drvdata(pdev);
spear_rtc_disable_interrupt(config);
clk_disable(config->clk);
}
#ifdef CONFIG_OF
static const struct of_device_id spear_rtc_id_table[] = {
{ .compatible = "st,spear600-rtc" },
{}
};
MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
#endif
static struct platform_driver spear_rtc_driver = {
.probe = spear_rtc_probe,
.remove = __devexit_p(spear_rtc_remove),
.suspend = spear_rtc_suspend,
.resume = spear_rtc_resume,
.shutdown = spear_rtc_shutdown,
.driver = {
.name = "rtc-spear",
.of_match_table = of_match_ptr(spear_rtc_id_table),
},
};
module_platform_driver(spear_rtc_driver);
MODULE_ALIAS("platform:rtc-spear");
MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL");
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