linux/drivers/rtc/rtc-ds3232.c
Lei Xu a2d6d2fa90 drivers/rtc/rtc-ds3232.c: fix time range difference between linux and RTC chip
In linux rtc_time struct, tm_mon range is 0~11, tm_wday range is 0~6,
while in RTC HW REG, month range is 1~12, day of the week range is 1~7,
this patch adjusts difference of them.

The efect of this bug was that most of month will be operated on as the
next month by the hardware (When in Jan it maybe even worse).  For
example, if in May, software wrote 4 to the hardware, which handled it as
April.  Then the logic would be different between software and hardware,
which would cause weird things to happen.

Signed-off-by: Lei Xu <B33228@freescale.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Jack Lan <jack.lan@freescale.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:37 -08:00

510 lines
12 KiB
C

/*
* RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
*
* Copyright (C) 2009-2011 Freescale Semiconductor.
* Author: Jack Lan <jack.lan@freescale.com>
*
* 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.
*/
/*
* It would be more efficient to use i2c msgs/i2c_transfer directly but, as
* recommened in .../Documentation/i2c/writing-clients section
* "Sending and receiving", using SMBus level communication is preferred.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#define DS3232_REG_SECONDS 0x00
#define DS3232_REG_MINUTES 0x01
#define DS3232_REG_HOURS 0x02
#define DS3232_REG_AMPM 0x02
#define DS3232_REG_DAY 0x03
#define DS3232_REG_DATE 0x04
#define DS3232_REG_MONTH 0x05
#define DS3232_REG_CENTURY 0x05
#define DS3232_REG_YEAR 0x06
#define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */
#define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */
#define DS3232_REG_CR 0x0E /* Control register */
# define DS3232_REG_CR_nEOSC 0x80
# define DS3232_REG_CR_INTCN 0x04
# define DS3232_REG_CR_A2IE 0x02
# define DS3232_REG_CR_A1IE 0x01
#define DS3232_REG_SR 0x0F /* control/status register */
# define DS3232_REG_SR_OSF 0x80
# define DS3232_REG_SR_BSY 0x04
# define DS3232_REG_SR_A2F 0x02
# define DS3232_REG_SR_A1F 0x01
struct ds3232 {
struct i2c_client *client;
struct rtc_device *rtc;
struct work_struct work;
/* The mutex protects alarm operations, and prevents a race
* between the enable_irq() in the workqueue and the free_irq()
* in the remove function.
*/
struct mutex mutex;
int exiting;
};
static struct i2c_driver ds3232_driver;
static int ds3232_check_rtc_status(struct i2c_client *client)
{
int ret = 0;
int control, stat;
stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
if (stat < 0)
return stat;
if (stat & DS3232_REG_SR_OSF)
dev_warn(&client->dev,
"oscillator discontinuity flagged, "
"time unreliable\n");
stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
if (ret < 0)
return ret;
/* If the alarm is pending, clear it before requesting
* the interrupt, so an interrupt event isn't reported
* before everything is initialized.
*/
control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
if (control < 0)
return control;
control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
control |= DS3232_REG_CR_INTCN;
return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
}
static int ds3232_read_time(struct device *dev, struct rtc_time *time)
{
struct i2c_client *client = to_i2c_client(dev);
int ret;
u8 buf[7];
unsigned int year, month, day, hour, minute, second;
unsigned int week, twelve_hr, am_pm;
unsigned int century, add_century = 0;
ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf);
if (ret < 0)
return ret;
if (ret < 7)
return -EIO;
second = buf[0];
minute = buf[1];
hour = buf[2];
week = buf[3];
day = buf[4];
month = buf[5];
year = buf[6];
/* Extract additional information for AM/PM and century */
twelve_hr = hour & 0x40;
am_pm = hour & 0x20;
century = month & 0x80;
/* Write to rtc_time structure */
time->tm_sec = bcd2bin(second);
time->tm_min = bcd2bin(minute);
if (twelve_hr) {
/* Convert to 24 hr */
if (am_pm)
time->tm_hour = bcd2bin(hour & 0x1F) + 12;
else
time->tm_hour = bcd2bin(hour & 0x1F);
} else {
time->tm_hour = bcd2bin(hour);
}
/* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
time->tm_wday = bcd2bin(week) - 1;
time->tm_mday = bcd2bin(day);
/* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
time->tm_mon = bcd2bin(month & 0x7F) - 1;
if (century)
add_century = 100;
time->tm_year = bcd2bin(year) + add_century;
return rtc_valid_tm(time);
}
static int ds3232_set_time(struct device *dev, struct rtc_time *time)
{
struct i2c_client *client = to_i2c_client(dev);
u8 buf[7];
/* Extract time from rtc_time and load into ds3232*/
buf[0] = bin2bcd(time->tm_sec);
buf[1] = bin2bcd(time->tm_min);
buf[2] = bin2bcd(time->tm_hour);
/* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
buf[3] = bin2bcd(time->tm_wday + 1);
buf[4] = bin2bcd(time->tm_mday); /* Date */
/* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
buf[5] = bin2bcd(time->tm_mon + 1);
if (time->tm_year >= 100) {
buf[5] |= 0x80;
buf[6] = bin2bcd(time->tm_year - 100);
} else {
buf[6] = bin2bcd(time->tm_year);
}
return i2c_smbus_write_i2c_block_data(client,
DS3232_REG_SECONDS, 7, buf);
}
/*
* DS3232 has two alarm, we only use alarm1
* According to linux specification, only support one-shot alarm
* no periodic alarm mode
*/
static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds3232 *ds3232 = i2c_get_clientdata(client);
int control, stat;
int ret;
u8 buf[4];
mutex_lock(&ds3232->mutex);
ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
if (ret < 0)
goto out;
stat = ret;
ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
if (ret < 0)
goto out;
control = ret;
ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
if (ret < 0)
goto out;
alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
alarm->time.tm_mon = -1;
alarm->time.tm_year = -1;
alarm->time.tm_wday = -1;
alarm->time.tm_yday = -1;
alarm->time.tm_isdst = -1;
alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
alarm->pending = !!(stat & DS3232_REG_SR_A1F);
ret = 0;
out:
mutex_unlock(&ds3232->mutex);
return ret;
}
/*
* linux rtc-module does not support wday alarm
* and only 24h time mode supported indeed
*/
static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds3232 *ds3232 = i2c_get_clientdata(client);
int control, stat;
int ret;
u8 buf[4];
if (client->irq <= 0)
return -EINVAL;
mutex_lock(&ds3232->mutex);
buf[0] = bin2bcd(alarm->time.tm_sec);
buf[1] = bin2bcd(alarm->time.tm_min);
buf[2] = bin2bcd(alarm->time.tm_hour);
buf[3] = bin2bcd(alarm->time.tm_mday);
/* clear alarm interrupt enable bit */
ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
if (ret < 0)
goto out;
control = ret;
control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
if (ret < 0)
goto out;
/* clear any pending alarm flag */
ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
if (ret < 0)
goto out;
stat = ret;
stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
if (ret < 0)
goto out;
ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
if (alarm->enabled) {
control |= DS3232_REG_CR_A1IE;
ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
}
out:
mutex_unlock(&ds3232->mutex);
return ret;
}
static void ds3232_update_alarm(struct i2c_client *client)
{
struct ds3232 *ds3232 = i2c_get_clientdata(client);
int control;
int ret;
u8 buf[4];
mutex_lock(&ds3232->mutex);
ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
if (ret < 0)
goto unlock;
buf[0] = bcd2bin(buf[0]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
0x80 : buf[0];
buf[1] = bcd2bin(buf[1]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
0x80 : buf[1];
buf[2] = bcd2bin(buf[2]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
0x80 : buf[2];
buf[3] = bcd2bin(buf[3]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
0x80 : buf[3];
ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
if (ret < 0)
goto unlock;
control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
if (control < 0)
goto unlock;
if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF))
/* enable alarm1 interrupt */
control |= DS3232_REG_CR_A1IE;
else
/* disable alarm1 interrupt */
control &= ~(DS3232_REG_CR_A1IE);
i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
unlock:
mutex_unlock(&ds3232->mutex);
}
static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds3232 *ds3232 = i2c_get_clientdata(client);
if (client->irq <= 0)
return -EINVAL;
if (enabled)
ds3232->rtc->irq_data |= RTC_AF;
else
ds3232->rtc->irq_data &= ~RTC_AF;
ds3232_update_alarm(client);
return 0;
}
static int ds3232_update_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds3232 *ds3232 = i2c_get_clientdata(client);
if (client->irq <= 0)
return -EINVAL;
if (enabled)
ds3232->rtc->irq_data |= RTC_UF;
else
ds3232->rtc->irq_data &= ~RTC_UF;
ds3232_update_alarm(client);
return 0;
}
static irqreturn_t ds3232_irq(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct ds3232 *ds3232 = i2c_get_clientdata(client);
disable_irq_nosync(irq);
schedule_work(&ds3232->work);
return IRQ_HANDLED;
}
static void ds3232_work(struct work_struct *work)
{
struct ds3232 *ds3232 = container_of(work, struct ds3232, work);
struct i2c_client *client = ds3232->client;
int stat, control;
mutex_lock(&ds3232->mutex);
stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
if (stat < 0)
goto unlock;
if (stat & DS3232_REG_SR_A1F) {
control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
if (control < 0)
goto out;
/* disable alarm1 interrupt */
control &= ~(DS3232_REG_CR_A1IE);
i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
/* clear the alarm pend flag */
stat &= ~DS3232_REG_SR_A1F;
i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
}
out:
if (!ds3232->exiting)
enable_irq(client->irq);
unlock:
mutex_unlock(&ds3232->mutex);
}
static const struct rtc_class_ops ds3232_rtc_ops = {
.read_time = ds3232_read_time,
.set_time = ds3232_set_time,
.read_alarm = ds3232_read_alarm,
.set_alarm = ds3232_set_alarm,
.alarm_irq_enable = ds3232_alarm_irq_enable,
.update_irq_enable = ds3232_update_irq_enable,
};
static int __devinit ds3232_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds3232 *ds3232;
int ret;
ds3232 = kzalloc(sizeof(struct ds3232), GFP_KERNEL);
if (!ds3232)
return -ENOMEM;
ds3232->client = client;
i2c_set_clientdata(client, ds3232);
INIT_WORK(&ds3232->work, ds3232_work);
mutex_init(&ds3232->mutex);
ret = ds3232_check_rtc_status(client);
if (ret)
goto out_free;
ds3232->rtc = rtc_device_register(client->name, &client->dev,
&ds3232_rtc_ops, THIS_MODULE);
if (IS_ERR(ds3232->rtc)) {
ret = PTR_ERR(ds3232->rtc);
dev_err(&client->dev, "unable to register the class device\n");
goto out_irq;
}
if (client->irq >= 0) {
ret = request_irq(client->irq, ds3232_irq, 0,
"ds3232", client);
if (ret) {
dev_err(&client->dev, "unable to request IRQ\n");
goto out_free;
}
}
return 0;
out_irq:
if (client->irq >= 0)
free_irq(client->irq, client);
out_free:
kfree(ds3232);
return ret;
}
static int __devexit ds3232_remove(struct i2c_client *client)
{
struct ds3232 *ds3232 = i2c_get_clientdata(client);
if (client->irq >= 0) {
mutex_lock(&ds3232->mutex);
ds3232->exiting = 1;
mutex_unlock(&ds3232->mutex);
free_irq(client->irq, client);
cancel_work_sync(&ds3232->work);
}
rtc_device_unregister(ds3232->rtc);
kfree(ds3232);
return 0;
}
static const struct i2c_device_id ds3232_id[] = {
{ "ds3232", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds3232_id);
static struct i2c_driver ds3232_driver = {
.driver = {
.name = "rtc-ds3232",
.owner = THIS_MODULE,
},
.probe = ds3232_probe,
.remove = __devexit_p(ds3232_remove),
.id_table = ds3232_id,
};
static int __init ds3232_init(void)
{
return i2c_add_driver(&ds3232_driver);
}
static void __exit ds3232_exit(void)
{
i2c_del_driver(&ds3232_driver);
}
module_init(ds3232_init);
module_exit(ds3232_exit);
MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>");
MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver");
MODULE_LICENSE("GPL");