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linux/drivers/rtc/rtc-ds1307.c
Austin Boyle 9eab0a788d rtc: ds1307: generalise ram size and offset 
Generalise NVRAM to support RAM with other size and offset, such as the
64 bytes of SRAM on the mcp7941x.

[rdunlap@xenotime.net: fix printk format warning]
Signed-off-by: Austin Boyle <Austin.Boyle@aviatnet.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: David Anders <danders.dev@gmail.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 16:58:40 -07:00

960 lines
25 KiB
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/*
* 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,
last_ds_type /* always last */
/* 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];
u16 nvram_offset;
struct bin_attribute *nvram;
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 alarm:1;
u16 nvram_offset;
u16 nvram_size;
};
static const struct chip_desc chips[last_ds_type] = {
[ds_1307] = {
.nvram_offset = 8,
.nvram_size = 56,
},
[ds_1337] = {
.alarm = 1,
},
[ds_1338] = {
.nvram_offset = 8,
.nvram_size = 56,
},
[ds_1339] = {
.alarm = 1,
},
[ds_3231] = {
.alarm = 1,
},
[mcp7941x] = {
/* this is battery backed SRAM */
.nvram_offset = 0x20,
.nvram_size = 0x40,
},
};
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:
/*
* these bits were cleared when preparing the date/time
* values and need to be set again before writing the
* buffer out to the device.
*/
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,
};
/*----------------------------------------------------------------------*/
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 >= ds1307->nvram->size))
return 0;
if ((off + count) > ds1307->nvram->size)
count = ds1307->nvram->size - off;
if (unlikely(!count))
return count;
result = ds1307->read_block_data(client, ds1307->nvram_offset + 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 >= ds1307->nvram->size))
return -EFBIG;
if ((off + count) > ds1307->nvram->size)
count = ds1307->nvram->size - off;
if (unlikely(!count))
return count;
result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
count, buf);
if (result < 0) {
dev_err(&client->dev, "%s error %d\n", "nvram write", result);
return result;
}
return count;
}
/*----------------------------------------------------------------------*/
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;
ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
if (!ds1307)
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:
/* 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 (ds1307->client->irq > 0 && chip->alarm) {
INIT_WORK(&ds1307->work, ds1307_work);
ds1307->regs[0] |= DS1337_BIT_INTCN
| bbsqi_bitpos[ds1307->type];
ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
want_irq = true;
}
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;
default:
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->nvram_size) {
ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
GFP_KERNEL);
if (!ds1307->nvram) {
err = -ENOMEM;
goto exit_nvram;
}
ds1307->nvram->attr.name = "nvram";
ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
ds1307->nvram->read = ds1307_nvram_read,
ds1307->nvram->write = ds1307_nvram_write,
ds1307->nvram->size = chip->nvram_size;
ds1307->nvram_offset = chip->nvram_offset;
err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
if (err) {
kfree(ds1307->nvram);
goto exit_nvram;
}
set_bit(HAS_NVRAM, &ds1307->flags);
dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
}
return 0;
exit_nvram:
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, ds1307->nvram);
kfree(ds1307->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,
};
module_i2c_driver(ds1307_driver);
MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
MODULE_LICENSE("GPL");
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