/*
* rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
*
* Copyright (C) 2005 James Chapman (ds1337 core)
* Copyright (C) 2006 David Brownell
*
* 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.
*
* If the I2C "force" mechanism is used, we assume the chip is a ds1337.
* (Much better would be board-specific tables of I2C devices, along with
* the platform_data drivers would use to sort such issues out.)
*/
enum ds_type {
unknown = 0,
ds_1307, /* or ds1338, ... */
ds_1337, /* or ds1339, ... */
ds_1340, /* or st m41t00, ... */
// rs5c372 too? different address...
};
static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
I2C_CLIENT_INSMOD;
/* RTC registers don't differ much, except for the century flag */
#define DS1307_REG_SECS 0x00 /* 00-59 */
# define DS1307_BIT_CH 0x80
#define DS1307_REG_MIN 0x01 /* 00-59 */
#define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
# 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 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 RTC;
* be careful using them.
*/
#define DS1307_REG_CONTROL 0x07
# define DS1307_BIT_OUT 0x80
# 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 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 DS1337_REG_STATUS 0x0f
# define DS1337_BIT_OSF 0x80
# define DS1337_BIT_A2I 0x02
# define DS1337_BIT_A1I 0x01
#define DS1339_REG_TRICKLE 0x10
struct ds1307 {
u8 reg_addr;
u8 regs[8];
enum ds_type type;
struct i2c_msg msg[2];
struct i2c_client client;
struct rtc_device *rtc;
};
static int ds1307_get_time(struct device *dev, struct rtc_time *t)
{
struct ds1307 *ds1307 = dev_get_drvdata(dev);
int tmp;
/* read the RTC registers all at once */
ds1307->msg[1].flags = I2C_M_RD;
ds1307->msg[1].len = 7;
tmp = i2c_transfer(ds1307->client.adapter, ds1307->msg, 2);
if (tmp != 2) {
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);
return 0;
}
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", dt->tm_sec, dt->tm_min,
dt->tm_hour, dt->tm_mday,
dt->tm_mon, dt->tm_year, dt->tm_wday);
*buf++ = 0; /* first register addr */
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);
if (ds1307->type == ds_1337)
buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
else if (ds1307->type == ds_1340)
buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
| DS1340_BIT_CENTURY;
ds1307->msg[1].flags = 0;
ds1307->msg[1].len = 8;
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 = i2c_transfer(ds1307->client.adapter, &ds1307->msg[1], 1);
if (result != 1) {
dev_err(dev, "%s error %d\n", "write", tmp);
return -EIO;
}
return 0;
}
static const struct rtc_class_ops ds13xx_rtc_ops = {
.read_time = ds1307_get_time,
.set_time = ds1307_set_time,
};
static struct i2c_driver ds1307_driver;
static int __devinit
ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
{
struct ds1307 *ds1307;
int err = -ENODEV;
struct i2c_client *client;
int tmp;
if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
client = &ds1307->client;
client->addr = address;
client->adapter = adapter;
client->driver = &ds1307_driver;
client->flags = 0;
i2c_set_clientdata(client, ds1307);
ds1307->msg[0].addr = client->addr;
ds1307->msg[0].flags = 0;
ds1307->msg[0].len = 1;
ds1307->msg[0].buf = &ds1307->reg_addr;
ds1307->msg[1].addr = client->addr;
ds1307->msg[1].flags = I2C_M_RD;
ds1307->msg[1].len = sizeof(ds1307->regs);
ds1307->msg[1].buf = ds1307->regs;
/* HACK: "force" implies "needs ds1337-style-oscillator setup" */
if (kind >= 0) {
ds1307->type = ds_1337;
ds1307->reg_addr = DS1337_REG_CONTROL;
ds1307->msg[1].len = 2;
tmp = i2c_transfer(client->adapter, ds1307->msg, 2);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}
ds1307->reg_addr = 0;
ds1307->msg[1].len = sizeof(ds1307->regs);
/* oscillator is off; need to turn it on */
if ((ds1307->regs[0] & DS1337_BIT_nEOSC)
|| (ds1307->regs[1] & DS1337_BIT_OSF)) {
printk(KERN_ERR "no ds1337 oscillator code\n");
goto exit_free;
}
} else
ds1307->type = ds_1307;
read_rtc:
/* read RTC registers */
tmp = i2c_transfer(client->adapter, ds1307->msg, 2);
if (tmp != 2) {
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];
if (tmp & DS1307_BIT_CH) {
if (ds1307->type && ds1307->type != ds_1307) {
pr_debug("not a ds1307?\n");
goto exit_free;
}
ds1307->type = ds_1307;
/* this partial initialization should work for ds1307,
* ds1338, ds1340, st m41t00, and more.
*/
dev_warn(&client->dev, "oscillator started; SET TIME!\n");
i2c_smbus_write_byte_data(client, 0, 0);
goto read_rtc;
}
tmp = BCD2BIN(tmp & 0x7f);
if (tmp > 60)
goto exit_free;
tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
if (tmp > 60)
goto exit_free;
tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
if (tmp == 0 || tmp > 31)
goto exit_free;
tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
if (tmp == 0 || tmp > 12)
goto exit_free;
/* force into in 24 hour mode (most chips) or
* disable century bit (ds1340)
*/
tmp = ds1307->regs[DS1307_REG_HOUR];
if (tmp & (1 << 6)) {
if (tmp & (1 << 5))
tmp = BCD2BIN(tmp & 0x1f) + 12;
else
tmp = BCD2BIN(tmp);
i2c_smbus_write_byte_data(client,
DS1307_REG_HOUR,
BIN2BCD(tmp));
}
/* FIXME chips like 1337 can generate alarm irqs too; those are
* worth exposing through the API (especially when the irq is
* wakeup-capable).
*/
switch (ds1307->type) {
case unknown:
strlcpy(client->name, "unknown", I2C_NAME_SIZE);
break;
case ds_1307:
strlcpy(client->name, "ds1307", I2C_NAME_SIZE);
break;
case ds_1337:
strlcpy(client->name, "ds1337", I2C_NAME_SIZE);
break;
case ds_1340:
strlcpy(client->name, "ds1340", I2C_NAME_SIZE);
break;
}
/* Tell the I2C layer a new client has arrived */
if ((err = i2c_attach_client(client)))
goto exit_free;
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_detach;
}
return 0;
exit_detach:
i2c_detach_client(client);
exit_free:
kfree(ds1307);
exit:
return err;
}
static int __devinit
ds1307_attach_adapter(struct i2c_adapter *adapter)
{
if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
return 0;
return i2c_probe(adapter, &addr_data, ds1307_detect);
}
static int __devexit ds1307_detach_client(struct i2c_client *client)
{
int err;
struct ds1307 *ds1307 = i2c_get_clientdata(client);
rtc_device_unregister(ds1307->rtc);
if ((err = i2c_detach_client(client)))
return err;
kfree(ds1307);
return 0;
}
static struct i2c_driver ds1307_driver = {
.driver = {
.name = "ds1307",
.owner = THIS_MODULE,
},
.attach_adapter = ds1307_attach_adapter,
.detach_client = __devexit_p(ds1307_detach_client),
};
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");
