/*
* An I2C driver for the Philips PCF8563 RTC
* Copyright 2005-06 Tower Technologies
*
* Author: Alessandro Zummo <a.zummo@towertech.it>
* Maintainers: http://www.nslu2-linux.org/
*
* based on the other drivers in this same directory.
*
* http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
*
* 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/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#define DRV_VERSION "0.4.3"
#define PCF8563_REG_ST1 0x00 /* status */
#define PCF8563_REG_ST2 0x01
#define PCF8563_REG_SC 0x02 /* datetime */
#define PCF8563_REG_MN 0x03
#define PCF8563_REG_HR 0x04
#define PCF8563_REG_DM 0x05
#define PCF8563_REG_DW 0x06
#define PCF8563_REG_MO 0x07
#define PCF8563_REG_YR 0x08
#define PCF8563_REG_AMN 0x09 /* alarm */
#define PCF8563_REG_AHR 0x0A
#define PCF8563_REG_ADM 0x0B
#define PCF8563_REG_ADW 0x0C
#define PCF8563_REG_CLKO 0x0D /* clock out */
#define PCF8563_REG_TMRC 0x0E /* timer control */
#define PCF8563_REG_TMR 0x0F /* timer */
#define PCF8563_SC_LV 0x80 /* low voltage */
#define PCF8563_MO_C 0x80 /* century */
static struct i2c_driver pcf8563_driver;
struct pcf8563 {
struct rtc_device *rtc;
/*
* The meaning of MO_C bit varies by the chip type.
* From PCF8563 datasheet: this bit is toggled when the years
* register overflows from 99 to 00
* 0 indicates the century is 20xx
* 1 indicates the century is 19xx
* From RTC8564 datasheet: this bit indicates change of
* century. When the year digit data overflows from 99 to 00,
* this bit is set. By presetting it to 0 while still in the
* 20th century, it will be set in year 2000, ...
* There seems no reliable way to know how the system use this
* bit. So let's do it heuristically, assuming we are live in
* 1970...2069.
*/
int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
};
/*
* In the routines that deal directly with the pcf8563 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
unsigned char buf[13] = { PCF8563_REG_ST1 };
struct i2c_msg msgs[] = {
{ client->addr, 0, 1, buf }, /* setup read ptr */
{ client->addr, I2C_M_RD, 13, buf }, /* read status + date */
};
/* read registers */
if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
dev_info(&client->dev,
"low voltage detected, date/time is not reliable.\n");
dev_dbg(&client->dev,
"%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
__func__,
buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6], buf[7],
buf[8]);
tm->tm_sec = BCD2BIN(buf[PCF8563_REG_SC] & 0x7F);
tm->tm_min = BCD2BIN(buf[PCF8563_REG_MN] & 0x7F);
tm->tm_hour = BCD2BIN(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F);
tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]);
if (tm->tm_year < 70)
tm->tm_year += 100; /* assume we are in 1970...2069 */
/* detect the polarity heuristically. see note above. */
pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
(tm->tm_year >= 100) : (tm->tm_year < 100);
dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* the clock can give out invalid datetime, but we cannot return
* -EINVAL otherwise hwclock will refuse to set the time on bootup.
*/
if (rtc_valid_tm(tm) < 0)
dev_err(&client->dev, "retrieved date/time is not valid.\n");
return 0;
}
static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
int i, err;
unsigned char buf[9];
dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* hours, minutes and seconds */
buf[PCF8563_REG_SC] = BIN2BCD(tm->tm_sec);
buf[PCF8563_REG_MN] = BIN2BCD(tm->tm_min);
buf[PCF8563_REG_HR] = BIN2BCD(tm->tm_hour);
buf[PCF8563_REG_DM] = BIN2BCD(tm->tm_mday);
/* month, 1 - 12 */
buf[PCF8563_REG_MO] = BIN2BCD(tm->tm_mon + 1);
/* year and century */
buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100);
if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
buf[PCF8563_REG_MO] |= PCF8563_MO_C;
buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
/* write register's data */
for (i = 0; i < 7; i++) {
unsigned char data[2] = { PCF8563_REG_SC + i,
buf[PCF8563_REG_SC + i] };
err = i2c_master_send(client, data, sizeof(data));
if (err != sizeof(data)) {
dev_err(&client->dev,
"%s: err=%d addr=%02x, data=%02x\n",
__func__, err, data[0], data[1]);
return -EIO;
}
};
return 0;
}
struct pcf8563_limit
{
unsigned char reg;
unsigned char mask;
unsigned char min;
unsigned char max;
};
static int pcf8563_validate_client(struct i2c_client *client)
{
int i;
static const struct pcf8563_limit pattern[] = {
/* register, mask, min, max */
{ PCF8563_REG_SC, 0x7F, 0, 59 },
{ PCF8563_REG_MN, 0x7F, 0, 59 },
{ PCF8563_REG_HR, 0x3F, 0, 23 },
{ PCF8563_REG_DM, 0x3F, 0, 31 },
{ PCF8563_REG_MO, 0x1F, 0, 12 },
};
/* check limits (only registers with bcd values) */
for (i = 0; i < ARRAY_SIZE(pattern); i++) {
int xfer;
unsigned char value;
unsigned char buf = pattern[i].reg;
struct i2c_msg msgs[] = {
{ client->addr, 0, 1, &buf },
{ client->addr, I2C_M_RD, 1, &buf },
};
xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (xfer != ARRAY_SIZE(msgs)) {
dev_err(&client->dev,
"%s: could not read register 0x%02X\n",
__func__, pattern[i].reg);
return -EIO;
}
value = BCD2BIN(buf & pattern[i].mask);
if (value > pattern[i].max ||
value < pattern[i].min) {
dev_dbg(&client->dev,
"%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, "
"max=%d, value=%d, raw=0x%02X\n",
__func__, i, pattern[i].reg, pattern[i].mask,
pattern[i].min, pattern[i].max,
value, buf);
return -ENODEV;
}
}
return 0;
}
static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return pcf8563_get_datetime(to_i2c_client(dev), tm);
}
static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return pcf8563_set_datetime(to_i2c_client(dev), tm);
}
static const struct rtc_class_ops pcf8563_rtc_ops = {
.read_time = pcf8563_rtc_read_time,
.set_time = pcf8563_rtc_set_time,
};
static int pcf8563_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pcf8563 *pcf8563;
int err = 0;
dev_dbg(&client->dev, "%s\n", __func__);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
if (!pcf8563)
return -ENOMEM;
/* Verify the chip is really an PCF8563 */
if (pcf8563_validate_client(client) < 0) {
err = -ENODEV;
goto exit_kfree;
}
dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
&client->dev, &pcf8563_rtc_ops, THIS_MODULE);
if (IS_ERR(pcf8563->rtc)) {
err = PTR_ERR(pcf8563->rtc);
goto exit_kfree;
}
i2c_set_clientdata(client, pcf8563);
return 0;
exit_kfree:
kfree(pcf8563);
return err;
}
static int pcf8563_remove(struct i2c_client *client)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
if (pcf8563->rtc)
rtc_device_unregister(pcf8563->rtc);
kfree(pcf8563);
return 0;
}
static const struct i2c_device_id pcf8563_id[] = {
{ "pcf8563", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8563_id);
static struct i2c_driver pcf8563_driver = {
.driver = {
.name = "rtc-pcf8563",
},
.probe = pcf8563_probe,
.remove = pcf8563_remove,
.id_table = pcf8563_id,
};
static int __init pcf8563_init(void)
{
return i2c_add_driver(&pcf8563_driver);
}
static void __exit pcf8563_exit(void)
{
i2c_del_driver(&pcf8563_driver);
}
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
module_init(pcf8563_init);
module_exit(pcf8563_exit);
