linux-stable/drivers/rtc/rtc-pcf8563.c
Atsushi Nemoto cbb9450234 [PATCH] rtc-pcf8563: detect polarity of century bit automatically
The usage of the century bit was inverted on 2.6.19 following to PCF8563's
description, but it was not match to usage suggested by RTC8564's
datasheet.  Anyway what MO_C=1 means can vary on each platform.  This patch
is to detect its polarity in get_datetime routine.  The default value of
c_polarity is 0 (MO_C=1 means 19xx) so that this patch does not change
current behavior even if get_datetime was not called before set_datetime.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@teamlog.com>
Cc: <stable@kernel.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 09:25:46 -08:00

370 lines
9.5 KiB
C

/*
* 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 "0.4.2"
/* Addresses to scan: none
* This chip cannot be reliably autodetected. An empty eeprom
* located at 0x51 will pass the validation routine due to
* the way the registers are implemented.
*/
static unsigned short normal_i2c[] = { I2C_CLIENT_END };
/* Module parameters */
I2C_CLIENT_INSMOD;
#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 */
struct pcf8563 {
struct i2c_client client;
/*
* 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 */
};
static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind);
static int pcf8563_detach(struct i2c_client *client);
/*
* 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 = container_of(client, struct pcf8563, 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", __FUNCTION__);
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",
__FUNCTION__,
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",
__FUNCTION__,
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 = container_of(client, struct pcf8563, 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",
__FUNCTION__,
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",
__FUNCTION__, 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",
__FUNCTION__, 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",
__FUNCTION__, 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_attach(struct i2c_adapter *adapter)
{
return i2c_probe(adapter, &addr_data, pcf8563_probe);
}
static struct i2c_driver pcf8563_driver = {
.driver = {
.name = "pcf8563",
},
.id = I2C_DRIVERID_PCF8563,
.attach_adapter = &pcf8563_attach,
.detach_client = &pcf8563_detach,
};
static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind)
{
struct pcf8563 *pcf8563;
struct i2c_client *client;
struct rtc_device *rtc;
int err = 0;
dev_dbg(adapter->class_dev.dev, "%s\n", __FUNCTION__);
if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
err = -ENODEV;
goto exit;
}
if (!(pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
client = &pcf8563->client;
client->addr = address;
client->driver = &pcf8563_driver;
client->adapter = adapter;
strlcpy(client->name, pcf8563_driver.driver.name, I2C_NAME_SIZE);
/* Verify the chip is really an PCF8563 */
if (kind < 0) {
if (pcf8563_validate_client(client) < 0) {
err = -ENODEV;
goto exit_kfree;
}
}
/* Inform the i2c layer */
if ((err = i2c_attach_client(client)))
goto exit_kfree;
dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
rtc = rtc_device_register(pcf8563_driver.driver.name, &client->dev,
&pcf8563_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
err = PTR_ERR(rtc);
goto exit_detach;
}
i2c_set_clientdata(client, rtc);
return 0;
exit_detach:
i2c_detach_client(client);
exit_kfree:
kfree(pcf8563);
exit:
return err;
}
static int pcf8563_detach(struct i2c_client *client)
{
struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);
int err;
struct rtc_device *rtc = i2c_get_clientdata(client);
if (rtc)
rtc_device_unregister(rtc);
if ((err = i2c_detach_client(client)))
return err;
kfree(pcf8563);
return 0;
}
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);