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linux/drivers/rtc/rtc-ds1307.c
David Anders 43fcb81550 rtc: add initial support for mcp7941x parts 
Add initial support for the microchip mcp7941x series of real time clocks.

The mcp7941x series is generally compatible with the ds1307 and ds1337 rtc
devices from dallas semiconductor.  minor differences include a backup
battery enable bit, and the polarity of the oscillator enable bit.

Signed-off-by: David Anders <danders.dev@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:58 -07:00

955 lines
24 KiB
C
Raw Blame History

/*
* rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
*
* Copyright (C) 2005 James Chapman (ds1337 core)
* Copyright (C) 2006 David Brownell
* Copyright (C) 2009 Matthias Fuchs (rx8025 support)
*
* 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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
/* We can't determine type by probing, but if we expect pre-Linux code
* to have set the chip up as a clock (turning on the oscillator and
* setting the date and time), Linux can ignore the non-clock features.
* That's a natural job for a factory or repair bench.
*/
enum ds_type {
ds_1307,
ds_1337,
ds_1338,
ds_1339,
ds_1340,
ds_1388,
ds_3231,
m41t00,
mcp7941x,
rx_8025,
// rs5c372 too? different address...
};
/* RTC registers don't differ much, except for the century flag */
#define DS1307_REG_SECS 0x00 /* 00-59 */
# define DS1307_BIT_CH 0x80
# define DS1340_BIT_nEOSC 0x80
# define MCP7941X_BIT_ST 0x80
#define DS1307_REG_MIN 0x01 /* 00-59 */
#define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
# define DS1307_BIT_12HR 0x40 /* in REG_HOUR */
# define DS1307_BIT_PM 0x20 /* in REG_HOUR */
# define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */
# define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */
#define DS1307_REG_WDAY 0x03 /* 01-07 */
# define MCP7941X_BIT_VBATEN 0x08
#define DS1307_REG_MDAY 0x04 /* 01-31 */
#define DS1307_REG_MONTH 0x05 /* 01-12 */
# define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */
#define DS1307_REG_YEAR 0x06 /* 00-99 */
/* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
* start at 7, and they differ a LOT. Only control and status matter for
* basic RTC date and time functionality; be careful using them.
*/
#define DS1307_REG_CONTROL 0x07 /* or ds1338 */
# define DS1307_BIT_OUT 0x80
# define DS1338_BIT_OSF 0x20
# define DS1307_BIT_SQWE 0x10
# define DS1307_BIT_RS1 0x02
# define DS1307_BIT_RS0 0x01
#define DS1337_REG_CONTROL 0x0e
# define DS1337_BIT_nEOSC 0x80
# define DS1339_BIT_BBSQI 0x20
# define DS3231_BIT_BBSQW 0x40 /* same as BBSQI */
# define DS1337_BIT_RS2 0x10
# define DS1337_BIT_RS1 0x08
# define DS1337_BIT_INTCN 0x04
# define DS1337_BIT_A2IE 0x02
# define DS1337_BIT_A1IE 0x01
#define DS1340_REG_CONTROL 0x07
# define DS1340_BIT_OUT 0x80
# define DS1340_BIT_FT 0x40
# define DS1340_BIT_CALIB_SIGN 0x20
# define DS1340_M_CALIBRATION 0x1f
#define DS1340_REG_FLAG 0x09
# define DS1340_BIT_OSF 0x80
#define DS1337_REG_STATUS 0x0f
# define DS1337_BIT_OSF 0x80
# define DS1337_BIT_A2I 0x02
# define DS1337_BIT_A1I 0x01
#define DS1339_REG_ALARM1_SECS 0x07
#define DS1339_REG_TRICKLE 0x10
#define RX8025_REG_CTRL1 0x0e
# define RX8025_BIT_2412 0x20
#define RX8025_REG_CTRL2 0x0f
# define RX8025_BIT_PON 0x10
# define RX8025_BIT_VDET 0x40
# define RX8025_BIT_XST 0x20
struct ds1307 {
u8 offset; /* register's offset */
u8 regs[11];
enum ds_type type;
unsigned long flags;
#define HAS_NVRAM 0 /* bit 0 == sysfs file active */
#define HAS_ALARM 1 /* bit 1 == irq claimed */
struct i2c_client *client;
struct rtc_device *rtc;
struct work_struct work;
s32 (*read_block_data)(const struct i2c_client *client, u8 command,
u8 length, u8 *values);
s32 (*write_block_data)(const struct i2c_client *client, u8 command,
u8 length, const u8 *values);
};
struct chip_desc {
unsigned nvram56:1;
unsigned alarm:1;
};
static const struct chip_desc chips[] = {
[ds_1307] = {
.nvram56 = 1,
},
[ds_1337] = {
.alarm = 1,
},
[ds_1338] = {
.nvram56 = 1,
},
[ds_1339] = {
.alarm = 1,
},
[ds_1340] = {
},
[ds_3231] = {
.alarm = 1,
},
[m41t00] = {
},
[mcp7941x] = {
},
[rx_8025] = {
}, };
static const struct i2c_device_id ds1307_id[] = {
{ "ds1307", ds_1307 },
{ "ds1337", ds_1337 },
{ "ds1338", ds_1338 },
{ "ds1339", ds_1339 },
{ "ds1388", ds_1388 },
{ "ds1340", ds_1340 },
{ "ds3231", ds_3231 },
{ "m41t00", m41t00 },
{ "mcp7941x", mcp7941x },
{ "pt7c4338", ds_1307 },
{ "rx8025", rx_8025 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds1307_id);
/*----------------------------------------------------------------------*/
#define BLOCK_DATA_MAX_TRIES 10
static s32 ds1307_read_block_data_once(const struct i2c_client *client,
u8 command, u8 length, u8 *values)
{
s32 i, data;
for (i = 0; i < length; i++) {
data = i2c_smbus_read_byte_data(client, command + i);
if (data < 0)
return data;
values[i] = data;
}
return i;
}
static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
u8 length, u8 *values)
{
u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
s32 ret;
int tries = 0;
dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
ret = ds1307_read_block_data_once(client, command, length, values);
if (ret < 0)
return ret;
do {
if (++tries > BLOCK_DATA_MAX_TRIES) {
dev_err(&client->dev,
"ds1307_read_block_data failed\n");
return -EIO;
}
memcpy(oldvalues, values, length);
ret = ds1307_read_block_data_once(client, command, length,
values);
if (ret < 0)
return ret;
} while (memcmp(oldvalues, values, length));
return length;
}
static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
u8 length, const u8 *values)
{
u8 currvalues[I2C_SMBUS_BLOCK_MAX];
int tries = 0;
dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
do {
s32 i, ret;
if (++tries > BLOCK_DATA_MAX_TRIES) {
dev_err(&client->dev,
"ds1307_write_block_data failed\n");
return -EIO;
}
for (i = 0; i < length; i++) {
ret = i2c_smbus_write_byte_data(client, command + i,
values[i]);
if (ret < 0)
return ret;
}
ret = ds1307_read_block_data_once(client, command, length,
currvalues);
if (ret < 0)
return ret;
} while (memcmp(currvalues, values, length));
return length;
}
/*----------------------------------------------------------------------*/
/*
* The IRQ logic includes a "real" handler running in IRQ context just
* long enough to schedule this workqueue entry. We need a task context
* to talk to the RTC, since I2C I/O calls require that; and disable the
* IRQ until we clear its status on the chip, so that this handler can
* work with any type of triggering (not just falling edge).
*
* The ds1337 and ds1339 both have two alarms, but we only use the first
* one (with a "seconds" field). For ds1337 we expect nINTA is our alarm
* signal; ds1339 chips have only one alarm signal.
*/
static void ds1307_work(struct work_struct *work)
{
struct ds1307 *ds1307;
struct i2c_client *client;
struct mutex *lock;
int stat, control;
ds1307 = container_of(work, struct ds1307, work);
client = ds1307->client;
lock = &ds1307->rtc->ops_lock;
mutex_lock(lock);
stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
if (stat < 0)
goto out;
if (stat & DS1337_BIT_A1I) {
stat &= ~DS1337_BIT_A1I;
i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
if (control < 0)
goto out;
control &= ~DS1337_BIT_A1IE;
i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
}
out:
if (test_bit(HAS_ALARM, &ds1307->flags))
enable_irq(client->irq);
mutex_unlock(lock);
}
static irqreturn_t ds1307_irq(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct ds1307 *ds1307 = i2c_get_clientdata(client);
disable_irq_nosync(irq);
schedule_work(&ds1307->work);
return IRQ_HANDLED;
}
/*----------------------------------------------------------------------*/
static int ds1307_get_time(struct device *dev, struct rtc_time *t)
{
struct ds1307 *ds1307 = dev_get_drvdata(dev);
int tmp;
/* read the RTC date and time registers all at once */
tmp = ds1307->read_block_data(ds1307->client,
ds1307->offset, 7, ds1307->regs);
if (tmp != 7) {
dev_err(dev, "%s error %d\n", "read", tmp);
return -EIO;
}
dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
"read",
ds1307->regs[0], ds1307->regs[1],
ds1307->regs[2], ds1307->regs[3],
ds1307->regs[4], ds1307->regs[5],
ds1307->regs[6]);
t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
t->tm_hour = bcd2bin(tmp);
t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
t->tm_mon = bcd2bin(tmp) - 1;
/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
"read", t->tm_sec, t->tm_min,
t->tm_hour, t->tm_mday,
t->tm_mon, t->tm_year, t->tm_wday);
/* initial clock setting can be undefined */
return rtc_valid_tm(t);
}
static int ds1307_set_time(struct device *dev, struct rtc_time *t)
{
struct ds1307 *ds1307 = dev_get_drvdata(dev);
int result;
int tmp;
u8 *buf = ds1307->regs;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
"write", t->tm_sec, t->tm_min,
t->tm_hour, t->tm_mday,
t->tm_mon, t->tm_year, t->tm_wday);
buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
/* assume 20YY not 19YY */
tmp = t->tm_year - 100;
buf[DS1307_REG_YEAR] = bin2bcd(tmp);
switch (ds1307->type) {
case ds_1337:
case ds_1339:
case ds_3231:
buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
break;
case ds_1340:
buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
| DS1340_BIT_CENTURY;
break;
case mcp7941x:
buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
break;
default:
break;
}
dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
"write", buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6]);
result = ds1307->write_block_data(ds1307->client,
ds1307->offset, 7, buf);
if (result < 0) {
dev_err(dev, "%s error %d\n", "write", result);
return result;
}
return 0;
}
static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -EINVAL;
/* read all ALARM1, ALARM2, and status registers at once */
ret = ds1307->read_block_data(client,
DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
if (ret != 9) {
dev_err(dev, "%s error %d\n", "alarm read", ret);
return -EIO;
}
dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
"alarm read",
ds1307->regs[0], ds1307->regs[1],
ds1307->regs[2], ds1307->regs[3],
ds1307->regs[4], ds1307->regs[5],
ds1307->regs[6], ds1307->regs[7],
ds1307->regs[8]);
/* report alarm time (ALARM1); assume 24 hour and day-of-month modes,
* and that all four fields are checked matches
*/
t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
t->time.tm_mon = -1;
t->time.tm_year = -1;
t->time.tm_wday = -1;
t->time.tm_yday = -1;
t->time.tm_isdst = -1;
/* ... and status */
t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, enabled=%d, pending=%d\n",
"alarm read", t->time.tm_sec, t->time.tm_min,
t->time.tm_hour, t->time.tm_mday,
t->enabled, t->pending);
return 0;
}
static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
unsigned char *buf = ds1307->regs;
u8 control, status;
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -EINVAL;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, enabled=%d, pending=%d\n",
"alarm set", t->time.tm_sec, t->time.tm_min,
t->time.tm_hour, t->time.tm_mday,
t->enabled, t->pending);
/* read current status of both alarms and the chip */
ret = ds1307->read_block_data(client,
DS1339_REG_ALARM1_SECS, 9, buf);
if (ret != 9) {
dev_err(dev, "%s error %d\n", "alarm write", ret);
return -EIO;
}
control = ds1307->regs[7];
status = ds1307->regs[8];
dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
"alarm set (old status)",
ds1307->regs[0], ds1307->regs[1],
ds1307->regs[2], ds1307->regs[3],
ds1307->regs[4], ds1307->regs[5],
ds1307->regs[6], control, status);
/* set ALARM1, using 24 hour and day-of-month modes */
buf[0] = bin2bcd(t->time.tm_sec);
buf[1] = bin2bcd(t->time.tm_min);
buf[2] = bin2bcd(t->time.tm_hour);
buf[3] = bin2bcd(t->time.tm_mday);
/* set ALARM2 to non-garbage */
buf[4] = 0;
buf[5] = 0;
buf[6] = 0;
/* optionally enable ALARM1 */
buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
if (t->enabled) {
dev_dbg(dev, "alarm IRQ armed\n");
buf[7] |= DS1337_BIT_A1IE; /* only ALARM1 is used */
}
buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
ret = ds1307->write_block_data(client,
DS1339_REG_ALARM1_SECS, 9, buf);
if (ret < 0) {
dev_err(dev, "can't set alarm time\n");
return ret;
}
return 0;
}
static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -ENOTTY;
ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
if (ret < 0)
return ret;
if (enabled)
ret |= DS1337_BIT_A1IE;
else
ret &= ~DS1337_BIT_A1IE;
ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
if (ret < 0)
return ret;
return 0;
}
static const struct rtc_class_ops ds13xx_rtc_ops = {
.read_time = ds1307_get_time,
.set_time = ds1307_set_time,
.read_alarm = ds1337_read_alarm,
.set_alarm = ds1337_set_alarm,
.alarm_irq_enable = ds1307_alarm_irq_enable,
};
/*----------------------------------------------------------------------*/
#define NVRAM_SIZE 56
static ssize_t
ds1307_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client;
struct ds1307 *ds1307;
int result;
client = kobj_to_i2c_client(kobj);
ds1307 = i2c_get_clientdata(client);
if (unlikely(off >= NVRAM_SIZE))
return 0;
if ((off + count) > NVRAM_SIZE)
count = NVRAM_SIZE - off;
if (unlikely(!count))
return count;
result = ds1307->read_block_data(client, 8 + off, count, buf);
if (result < 0)
dev_err(&client->dev, "%s error %d\n", "nvram read", result);
return result;
}
static ssize_t
ds1307_nvram_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client;
struct ds1307 *ds1307;
int result;
client = kobj_to_i2c_client(kobj);
ds1307 = i2c_get_clientdata(client);
if (unlikely(off >= NVRAM_SIZE))
return -EFBIG;
if ((off + count) > NVRAM_SIZE)
count = NVRAM_SIZE - off;
if (unlikely(!count))
return count;
result = ds1307->write_block_data(client, 8 + off, count, buf);
if (result < 0) {
dev_err(&client->dev, "%s error %d\n", "nvram write", result);
return result;
}
return count;
}
static struct bin_attribute nvram = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.read = ds1307_nvram_read,
.write = ds1307_nvram_write,
.size = NVRAM_SIZE,
};
/*----------------------------------------------------------------------*/
static struct i2c_driver ds1307_driver;
static int __devinit ds1307_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds1307 *ds1307;
int err = -ENODEV;
int tmp;
const struct chip_desc *chip = &chips[id->driver_data];
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
int want_irq = false;
unsigned char *buf;
static const int bbsqi_bitpos[] = {
[ds_1337] = 0,
[ds_1339] = DS1339_BIT_BBSQI,
[ds_3231] = DS3231_BIT_BBSQW,
};
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
return -EIO;
if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
return -ENOMEM;
i2c_set_clientdata(client, ds1307);
ds1307->client = client;
ds1307->type = id->driver_data;
ds1307->offset = 0;
buf = ds1307->regs;
if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
} else {
ds1307->read_block_data = ds1307_read_block_data;
ds1307->write_block_data = ds1307_write_block_data;
}
switch (ds1307->type) {
case ds_1337:
case ds_1339:
case ds_3231:
/* has IRQ? */
if (ds1307->client->irq > 0 && chip->alarm) {
INIT_WORK(&ds1307->work, ds1307_work);
want_irq = true;
}
/* get registers that the "rtc" read below won't read... */
tmp = ds1307->read_block_data(ds1307->client,
DS1337_REG_CONTROL, 2, buf);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}
/* oscillator off? turn it on, so clock can tick. */
if (ds1307->regs[0] & DS1337_BIT_nEOSC)
ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
/* Using IRQ? Disable the square wave and both alarms.
* For some variants, be sure alarms can trigger when we're
* running on Vbackup (BBSQI/BBSQW)
*/
if (want_irq) {
ds1307->regs[0] |= DS1337_BIT_INTCN
| bbsqi_bitpos[ds1307->type];
ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
}
i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
ds1307->regs[0]);
/* oscillator fault? clear flag, and warn */
if (ds1307->regs[1] & DS1337_BIT_OSF) {
i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
ds1307->regs[1] & ~DS1337_BIT_OSF);
dev_warn(&client->dev, "SET TIME!\n");
}
break;
case rx_8025:
tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}
/* oscillator off? turn it on, so clock can tick. */
if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
ds1307->regs[1] |= RX8025_BIT_XST;
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL2 << 4 | 0x08,
ds1307->regs[1]);
dev_warn(&client->dev,
"oscillator stop detected - SET TIME!\n");
}
if (ds1307->regs[1] & RX8025_BIT_PON) {
ds1307->regs[1] &= ~RX8025_BIT_PON;
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL2 << 4 | 0x08,
ds1307->regs[1]);
dev_warn(&client->dev, "power-on detected\n");
}
if (ds1307->regs[1] & RX8025_BIT_VDET) {
ds1307->regs[1] &= ~RX8025_BIT_VDET;
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL2 << 4 | 0x08,
ds1307->regs[1]);
dev_warn(&client->dev, "voltage drop detected\n");
}
/* make sure we are running in 24hour mode */
if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
u8 hour;
/* switch to 24 hour mode */
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL1 << 4 | 0x08,
ds1307->regs[0] |
RX8025_BIT_2412);
tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}
/* correct hour */
hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
if (hour == 12)
hour = 0;
if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
hour += 12;
i2c_smbus_write_byte_data(client,
DS1307_REG_HOUR << 4 | 0x08,
hour);
}
break;
case ds_1388:
ds1307->offset = 1; /* Seconds starts at 1 */
break;
default:
break;
}
read_rtc:
/* read RTC registers */
tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
if (tmp != 8) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}
/* minimal sanity checking; some chips (like DS1340) don't
* specify the extra bits as must-be-zero, but there are
* still a few values that are clearly out-of-range.
*/
tmp = ds1307->regs[DS1307_REG_SECS];
switch (ds1307->type) {
case ds_1307:
case m41t00:
/* clock halted? turn it on, so clock can tick. */
if (tmp & DS1307_BIT_CH) {
i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
break;
case ds_1338:
/* clock halted? turn it on, so clock can tick. */
if (tmp & DS1307_BIT_CH)
i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
/* oscillator fault? clear flag, and warn */
if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
ds1307->regs[DS1307_REG_CONTROL]
& ~DS1338_BIT_OSF);
dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
break;
case ds_1340:
/* clock halted? turn it on, so clock can tick. */
if (tmp & DS1340_BIT_nEOSC)
i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
if (tmp < 0) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}
/* oscillator fault? clear flag, and warn */
if (tmp & DS1340_BIT_OSF) {
i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
dev_warn(&client->dev, "SET TIME!\n");
}
break;
case mcp7941x:
/* make sure that the backup battery is enabled */
if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
ds1307->regs[DS1307_REG_WDAY]
| MCP7941X_BIT_VBATEN);
}
/* clock halted? turn it on, so clock can tick. */
if (!(tmp & MCP7941X_BIT_ST)) {
i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
MCP7941X_BIT_ST);
dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
break;
case rx_8025:
case ds_1337:
case ds_1339:
case ds_1388:
case ds_3231:
break;
}
tmp = ds1307->regs[DS1307_REG_HOUR];
switch (ds1307->type) {
case ds_1340:
case m41t00:
/* NOTE: ignores century bits; fix before deploying
* systems that will run through year 2100.
*/
break;
case rx_8025:
break;
default:
if (!(tmp & DS1307_BIT_12HR))
break;
/* Be sure we're in 24 hour mode. Multi-master systems
* take note...
*/
tmp = bcd2bin(tmp & 0x1f);
if (tmp == 12)
tmp = 0;
if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
tmp += 12;
i2c_smbus_write_byte_data(client,
ds1307->offset + DS1307_REG_HOUR,
bin2bcd(tmp));
}
ds1307->rtc = rtc_device_register(client->name, &client->dev,
&ds13xx_rtc_ops, THIS_MODULE);
if (IS_ERR(ds1307->rtc)) {
err = PTR_ERR(ds1307->rtc);
dev_err(&client->dev,
"unable to register the class device\n");
goto exit_free;
}
if (want_irq) {
err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
ds1307->rtc->name, client);
if (err) {
dev_err(&client->dev,
"unable to request IRQ!\n");
goto exit_irq;
}
device_set_wakeup_capable(&client->dev, 1);
set_bit(HAS_ALARM, &ds1307->flags);
dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
}
if (chip->nvram56) {
err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
if (err == 0) {
set_bit(HAS_NVRAM, &ds1307->flags);
dev_info(&client->dev, "56 bytes nvram\n");
}
}
return 0;
exit_irq:
rtc_device_unregister(ds1307->rtc);
exit_free:
kfree(ds1307);
return err;
}
static int __devexit ds1307_remove(struct i2c_client *client)
{
struct ds1307 *ds1307 = i2c_get_clientdata(client);
if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
free_irq(client->irq, client);
cancel_work_sync(&ds1307->work);
}
if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
sysfs_remove_bin_file(&client->dev.kobj, &nvram);
rtc_device_unregister(ds1307->rtc);
kfree(ds1307);
return 0;
}
static struct i2c_driver ds1307_driver = {
.driver = {
.name = "rtc-ds1307",
.owner = THIS_MODULE,
},
.probe = ds1307_probe,
.remove = __devexit_p(ds1307_remove),
.id_table = ds1307_id,
};
static int __init ds1307_init(void)
{
return i2c_add_driver(&ds1307_driver);
}
module_init(ds1307_init);
static void __exit ds1307_exit(void)
{
i2c_del_driver(&ds1307_driver);
}
module_exit(ds1307_exit);
MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
MODULE_LICENSE("GPL");
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