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linux-next/drivers/rtc/rtc-m41t80.c
Atsushi Nemoto caaff562e0 rtc: add rtc-m41t80 driver 
This is a new-style i2c driver for ST M41T80 series RTC chip, derived from
works by Alexander Bigga <ab@mycable.de> who wrote the original
rtc-m41txx.c based on drivers/i2c/chips/m41t00.c driver.

This driver supports M41T8[0-4] and M41ST8[457].  The old m41t00 driver
supports M41T00, M41T81 and M41T85(M41ST85).  While the M41T00 chip is now
supported by rtc-ds1307 driver, this driver does not include support for
the chip.

[akpm@linux-foundation.org: remove bogus `static']
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Alexander Bigga <ab@mycable.de>
Acked-by: Mark A. Greer <mgreer@mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:09 -07:00

630 lines
15 KiB
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/*
* I2C client/driver for the ST M41T80 family of i2c rtc chips.
*
* Author: Alexander Bigga <ab@mycable.de>
*
* Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
*
* 2006 (c) mycable GmbH
*
* 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/string.h>
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#define M41T80_REG_SSEC 0
#define M41T80_REG_SEC 1
#define M41T80_REG_MIN 2
#define M41T80_REG_HOUR 3
#define M41T80_REG_WDAY 4
#define M41T80_REG_DAY 5
#define M41T80_REG_MON 6
#define M41T80_REG_YEAR 7
#define M41T80_REG_ALARM_MON 0xa
#define M41T80_REG_ALARM_DAY 0xb
#define M41T80_REG_ALARM_HOUR 0xc
#define M41T80_REG_ALARM_MIN 0xd
#define M41T80_REG_ALARM_SEC 0xe
#define M41T80_REG_FLAGS 0xf
#define M41T80_REG_SQW 0x13
#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
#define M41T80_ALARM_REG_SIZE \
(M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
#define M41T80_FEATURE_HT (1 << 0)
#define M41T80_FEATURE_BL (1 << 1)
#define DRV_VERSION "0.05"
struct m41t80_chip_info {
const char *name;
u8 features;
};
static const struct m41t80_chip_info m41t80_chip_info_tbl[] = {
{
.name = "m41t80",
.features = 0,
},
{
.name = "m41t81",
.features = M41T80_FEATURE_HT,
},
{
.name = "m41t81s",
.features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
},
{
.name = "m41t82",
.features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
},
{
.name = "m41t83",
.features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
},
{
.name = "m41st84",
.features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
},
{
.name = "m41st85",
.features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
},
{
.name = "m41st87",
.features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
},
};
struct m41t80_data {
const struct m41t80_chip_info *chip;
struct rtc_device *rtc;
};
static int m41t80_get_datetime(struct i2c_client *client,
struct rtc_time *tm)
{
u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = dt_addr,
},
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
.buf = buf + M41T80_REG_SEC,
},
};
if (i2c_transfer(client->adapter, msgs, 2) < 0) {
dev_err(&client->dev, "read error\n");
return -EIO;
}
tm->tm_sec = BCD2BIN(buf[M41T80_REG_SEC] & 0x7f);
tm->tm_min = BCD2BIN(buf[M41T80_REG_MIN] & 0x7f);
tm->tm_hour = BCD2BIN(buf[M41T80_REG_HOUR] & 0x3f);
tm->tm_mday = BCD2BIN(buf[M41T80_REG_DAY] & 0x3f);
tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
tm->tm_mon = BCD2BIN(buf[M41T80_REG_MON] & 0x1f) - 1;
/* assume 20YY not 19YY, and ignore the Century Bit */
tm->tm_year = BCD2BIN(buf[M41T80_REG_YEAR]) + 100;
return 0;
}
/* Sets the given date and time to the real time clock. */
static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
u8 *buf = &wbuf[1];
u8 dt_addr[1] = { M41T80_REG_SEC };
struct i2c_msg msgs_in[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = dt_addr,
},
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
.buf = buf + M41T80_REG_SEC,
},
};
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1 + M41T80_DATETIME_REG_SIZE,
.buf = wbuf,
},
};
/* Read current reg values into buf[1..7] */
if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
dev_err(&client->dev, "read error\n");
return -EIO;
}
wbuf[0] = 0; /* offset into rtc's regs */
/* Merge time-data and register flags into buf[0..7] */
buf[M41T80_REG_SSEC] = 0;
buf[M41T80_REG_SEC] =
BIN2BCD(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
buf[M41T80_REG_MIN] =
BIN2BCD(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
buf[M41T80_REG_HOUR] =
BIN2BCD(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
buf[M41T80_REG_WDAY] =
(tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
buf[M41T80_REG_DAY] =
BIN2BCD(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
buf[M41T80_REG_MON] =
BIN2BCD(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
/* assume 20YY not 19YY */
buf[M41T80_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
if (i2c_transfer(client->adapter, msgs, 1) != 1) {
dev_err(&client->dev, "write error\n");
return -EIO;
}
return 0;
}
#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
{
struct i2c_client *client = to_i2c_client(dev);
struct m41t80_data *clientdata = i2c_get_clientdata(client);
u8 reg;
if (clientdata->chip->features & M41T80_FEATURE_BL) {
reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
seq_printf(seq, "battery\t\t: %s\n",
(reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
}
return 0;
}
#else
#define m41t80_rtc_proc NULL
#endif
static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return m41t80_get_datetime(to_i2c_client(dev), tm);
}
static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return m41t80_set_datetime(to_i2c_client(dev), tm);
}
#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
static int
m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct i2c_client *client = to_i2c_client(dev);
int rc;
switch (cmd) {
case RTC_AIE_OFF:
case RTC_AIE_ON:
break;
default:
return -ENOIOCTLCMD;
}
rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (rc < 0)
goto err;
switch (cmd) {
case RTC_AIE_OFF:
rc &= ~M41T80_ALMON_AFE;
break;
case RTC_AIE_ON:
rc |= M41T80_ALMON_AFE;
break;
}
if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
goto err;
return 0;
err:
return -EIO;
}
#else
#define m41t80_rtc_ioctl NULL
#endif
static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
u8 *buf = &wbuf[1];
u8 *reg = buf - M41T80_REG_ALARM_MON;
u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
struct i2c_msg msgs_in[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = dt_addr,
},
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = M41T80_ALARM_REG_SIZE,
.buf = buf,
},
};
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1 + M41T80_ALARM_REG_SIZE,
.buf = wbuf,
},
};
if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
dev_err(&client->dev, "read error\n");
return -EIO;
}
reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
reg[M41T80_REG_ALARM_DAY] = 0;
reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
reg[M41T80_REG_ALARM_MIN] = 0;
reg[M41T80_REG_ALARM_SEC] = 0;
wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
BIN2BCD(t->time.tm_sec) : 0x80;
reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
BIN2BCD(t->time.tm_min) : 0x80;
reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
BIN2BCD(t->time.tm_hour) : 0x80;
reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
BIN2BCD(t->time.tm_mday) : 0x80;
if (t->time.tm_mon >= 0)
reg[M41T80_REG_ALARM_MON] |= BIN2BCD(t->time.tm_mon + 1);
else
reg[M41T80_REG_ALARM_DAY] |= 0x40;
if (i2c_transfer(client->adapter, msgs, 1) != 1) {
dev_err(&client->dev, "write error\n");
return -EIO;
}
if (t->enabled) {
reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
reg[M41T80_REG_ALARM_MON]) < 0) {
dev_err(&client->dev, "write error\n");
return -EIO;
}
}
return 0;
}
static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
u8 *reg = buf - M41T80_REG_ALARM_MON;
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = dt_addr,
},
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = M41T80_ALARM_REG_SIZE + 1,
.buf = buf,
},
};
if (i2c_transfer(client->adapter, msgs, 2) < 0) {
dev_err(&client->dev, "read error\n");
return -EIO;
}
t->time.tm_sec = -1;
t->time.tm_min = -1;
t->time.tm_hour = -1;
t->time.tm_mday = -1;
t->time.tm_mon = -1;
if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
t->time.tm_sec = BCD2BIN(reg[M41T80_REG_ALARM_SEC] & 0x7f);
if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
t->time.tm_min = BCD2BIN(reg[M41T80_REG_ALARM_MIN] & 0x7f);
if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
t->time.tm_hour = BCD2BIN(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
t->time.tm_mday = BCD2BIN(reg[M41T80_REG_ALARM_DAY] & 0x3f);
if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
t->time.tm_mon = BCD2BIN(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
t->time.tm_year = -1;
t->time.tm_wday = -1;
t->time.tm_yday = -1;
t->time.tm_isdst = -1;
t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
return 0;
}
static struct rtc_class_ops m41t80_rtc_ops = {
.read_time = m41t80_rtc_read_time,
.set_time = m41t80_rtc_set_time,
.read_alarm = m41t80_rtc_read_alarm,
.set_alarm = m41t80_rtc_set_alarm,
.proc = m41t80_rtc_proc,
.ioctl = m41t80_rtc_ioctl,
};
#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
static ssize_t m41t80_sysfs_show_flags(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
int val;
val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (val < 0)
return -EIO;
return sprintf(buf, "%#x\n", val);
}
static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
int val;
val = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
if (val < 0)
return -EIO;
val = (val >> 4) & 0xf;
switch (val) {
case 0:
break;
case 1:
val = 32768;
break;
default:
val = 32768 >> val;
}
return sprintf(buf, "%d\n", val);
}
static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
int almon, sqw;
int val = simple_strtoul(buf, NULL, 0);
if (val) {
if (!is_power_of_2(val))
return -EINVAL;
val = ilog2(val);
if (val == 15)
val = 1;
else if (val < 14)
val = 15 - val;
else
return -EINVAL;
}
/* disable SQW, set SQW frequency & re-enable */
almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (almon < 0)
return -EIO;
sqw = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
if (sqw < 0)
return -EIO;
sqw = (sqw & 0x0f) | (val << 4);
if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
almon & ~M41T80_ALMON_SQWE) < 0 ||
i2c_smbus_write_byte_data(client, M41T80_REG_SQW, sqw) < 0)
return -EIO;
if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
almon | M41T80_ALMON_SQWE) < 0)
return -EIO;
return count;
}
static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
static struct attribute *attrs[] = {
&dev_attr_flags.attr,
&dev_attr_sqwfreq.attr,
NULL,
};
static struct attribute_group attr_group = {
.attrs = attrs,
};
static int m41t80_sysfs_register(struct device *dev)
{
return sysfs_create_group(&dev->kobj, &attr_group);
}
#else
static int m41t80_sysfs_register(struct device *dev)
{
return 0;
}
#endif
/*
*****************************************************************************
*
* Driver Interface
*
*****************************************************************************
*/
static int m41t80_probe(struct i2c_client *client)
{
int i, rc = 0;
struct rtc_device *rtc = NULL;
struct rtc_time tm;
const struct m41t80_chip_info *chip;
struct m41t80_data *clientdata = NULL;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
| I2C_FUNC_SMBUS_BYTE_DATA)) {
rc = -ENODEV;
goto exit;
}
dev_info(&client->dev,
"chip found, driver version " DRV_VERSION "\n");
chip = NULL;
for (i = 0; i < ARRAY_SIZE(m41t80_chip_info_tbl); i++) {
if (!strcmp(m41t80_chip_info_tbl[i].name, client->name)) {
chip = &m41t80_chip_info_tbl[i];
break;
}
}
if (!chip) {
dev_err(&client->dev, "%s is not supported\n", client->name);
rc = -ENODEV;
goto exit;
}
clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
if (!clientdata) {
rc = -ENOMEM;
goto exit;
}
rtc = rtc_device_register(client->name, &client->dev,
&m41t80_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
rc = PTR_ERR(rtc);
rtc = NULL;
goto exit;
}
clientdata->rtc = rtc;
clientdata->chip = chip;
i2c_set_clientdata(client, clientdata);
/* Make sure HT (Halt Update) bit is cleared */
rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
if (rc < 0)
goto ht_err;
if (rc & M41T80_ALHOUR_HT) {
if (chip->features & M41T80_FEATURE_HT) {
m41t80_get_datetime(client, &tm);
dev_info(&client->dev, "HT bit was set!\n");
dev_info(&client->dev,
"Power Down at "
"%04i-%02i-%02i %02i:%02i:%02i\n",
tm.tm_year + 1900,
tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
tm.tm_min, tm.tm_sec);
}
if (i2c_smbus_write_byte_data(client,
M41T80_REG_ALARM_HOUR,
rc & ~M41T80_ALHOUR_HT) < 0)
goto ht_err;
}
/* Make sure ST (stop) bit is cleared */
rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
if (rc < 0)
goto st_err;
if (rc & M41T80_SEC_ST) {
if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
rc & ~M41T80_SEC_ST) < 0)
goto st_err;
}
rc = m41t80_sysfs_register(&client->dev);
if (rc)
goto exit;
return 0;
st_err:
rc = -EIO;
dev_err(&client->dev, "Can't clear ST bit\n");
goto exit;
ht_err:
rc = -EIO;
dev_err(&client->dev, "Can't clear HT bit\n");
goto exit;
exit:
if (rtc)
rtc_device_unregister(rtc);
kfree(clientdata);
return rc;
}
static int m41t80_remove(struct i2c_client *client)
{
struct m41t80_data *clientdata = i2c_get_clientdata(client);
struct rtc_device *rtc = clientdata->rtc;
if (rtc)
rtc_device_unregister(rtc);
kfree(clientdata);
return 0;
}
static struct i2c_driver m41t80_driver = {
.driver = {
.name = "m41t80",
},
.probe = m41t80_probe,
.remove = m41t80_remove,
};
static int __init m41t80_rtc_init(void)
{
return i2c_add_driver(&m41t80_driver);
}
static void __exit m41t80_rtc_exit(void)
{
i2c_del_driver(&m41t80_driver);
}
MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
module_init(m41t80_rtc_init);
module_exit(m41t80_rtc_exit);
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