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linux/drivers/rtc/rtc-x1205.c
Michael Hamel 471d47e322 rtc-x1205: Fix alarm set 
I have discovered that the current version of rtc-x1205.c does not work
correctly when asked to set the alarm time by the RTC_WKALM_SET ioctl()
call.  This happens because the alarm registers do not behave like the
current-time registers.  They are non-volatile.  Two things go wrong:

- the X1205 requires a 10 msec delay after any attempt to write to the
  non-volatile registers.  The x1205_set_datetime() routine does the write
  as 8 single-byte writes without any delay.  Only the first write
  succeeds.  The second is NAKed because the chip is busy.

- the X1205 resets the RWEL bit after any write to the non-volatile
  registers.  This would lock out any further writes after the first even
  with a 10msec delay.

I fix this by doing a single 8-byte write and then waiting 10msec for the
chip to be ready.  A side effect of this change is that it will speed up
x1205_rtc_set_time() which uses the same code.

I have also implemented the 'enable' bit in the rtc_wkalm structure, which
the existing driver does not attempt to do.  I have modified both
x1205_rtc_set_alarm() to set the AL0E bit, and x1205_rtc_read_alarm() to
return it.

I have tested this patch on a LinkSys NSLU2 under OpenWRT, but on no other
hardware.  On the NSLU2 the X1205 correctly asserts its IRQ pin when the
alarm time matches the current time.

[akpm@linux-foundation.org: clean up over-parenthesisation]
Signed-off-by: Michael Hamel <mhamel@adi.co.nz>
Signed-off-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>
2008-07-04 10:40:05 -07:00

661 lines
16 KiB
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/*
* An i2c driver for the Xicor/Intersil X1205 RTC
* Copyright 2004 Karen Spearel
* Copyright 2005 Alessandro Zummo
*
* please send all reports to:
* Karen Spearel <kas111 at gmail dot com>
* Alessandro Zummo <a.zummo@towertech.it>
*
* based on a lot of other RTC drivers.
*
* Information and datasheet:
* http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
*
* 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>
#include <linux/delay.h>
#define DRV_VERSION "1.0.8"
/* offsets into CCR area */
#define CCR_SEC 0
#define CCR_MIN 1
#define CCR_HOUR 2
#define CCR_MDAY 3
#define CCR_MONTH 4
#define CCR_YEAR 5
#define CCR_WDAY 6
#define CCR_Y2K 7
#define X1205_REG_SR 0x3F /* status register */
#define X1205_REG_Y2K 0x37
#define X1205_REG_DW 0x36
#define X1205_REG_YR 0x35
#define X1205_REG_MO 0x34
#define X1205_REG_DT 0x33
#define X1205_REG_HR 0x32
#define X1205_REG_MN 0x31
#define X1205_REG_SC 0x30
#define X1205_REG_DTR 0x13
#define X1205_REG_ATR 0x12
#define X1205_REG_INT 0x11
#define X1205_REG_0 0x10
#define X1205_REG_Y2K1 0x0F
#define X1205_REG_DWA1 0x0E
#define X1205_REG_YRA1 0x0D
#define X1205_REG_MOA1 0x0C
#define X1205_REG_DTA1 0x0B
#define X1205_REG_HRA1 0x0A
#define X1205_REG_MNA1 0x09
#define X1205_REG_SCA1 0x08
#define X1205_REG_Y2K0 0x07
#define X1205_REG_DWA0 0x06
#define X1205_REG_YRA0 0x05
#define X1205_REG_MOA0 0x04
#define X1205_REG_DTA0 0x03
#define X1205_REG_HRA0 0x02
#define X1205_REG_MNA0 0x01
#define X1205_REG_SCA0 0x00
#define X1205_CCR_BASE 0x30 /* Base address of CCR */
#define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */
#define X1205_SR_RTCF 0x01 /* Clock failure */
#define X1205_SR_WEL 0x02 /* Write Enable Latch */
#define X1205_SR_RWEL 0x04 /* Register Write Enable */
#define X1205_SR_AL0 0x20 /* Alarm 0 match */
#define X1205_DTR_DTR0 0x01
#define X1205_DTR_DTR1 0x02
#define X1205_DTR_DTR2 0x04
#define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */
#define X1205_INT_AL0E 0x20 /* Alarm 0 enable */
static struct i2c_driver x1205_driver;
/*
* In the routines that deal directly with the x1205 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
* Epoch is initialized as 2000. Time is set to UTC.
*/
static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
unsigned char reg_base)
{
unsigned char dt_addr[2] = { 0, reg_base };
unsigned char buf[8];
int i;
struct i2c_msg msgs[] = {
{ client->addr, 0, 2, dt_addr }, /* setup read ptr */
{ client->addr, I2C_M_RD, 8, buf }, /* read date */
};
/* read date registers */
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
dev_dbg(&client->dev,
"%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
"mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
__func__,
buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6], buf[7]);
/* Mask out the enable bits if these are alarm registers */
if (reg_base < X1205_CCR_BASE)
for (i = 0; i <= 4; i++)
buf[i] &= 0x7F;
tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
tm->tm_min = BCD2BIN(buf[CCR_MIN]);
tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
tm->tm_year = BCD2BIN(buf[CCR_YEAR])
+ (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
tm->tm_wday = buf[CCR_WDAY];
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);
return 0;
}
static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
{
static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
struct i2c_msg msgs[] = {
{ client->addr, 0, 2, sr_addr }, /* setup read ptr */
{ client->addr, I2C_M_RD, 1, sr }, /* read status */
};
/* read status register */
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
return 0;
}
static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
int datetoo, u8 reg_base, unsigned char alm_enable)
{
int i, xfer, nbytes;
unsigned char buf[8];
unsigned char rdata[10] = { 0, reg_base };
static const unsigned char wel[3] = { 0, X1205_REG_SR,
X1205_SR_WEL };
static const unsigned char rwel[3] = { 0, X1205_REG_SR,
X1205_SR_WEL | X1205_SR_RWEL };
static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
dev_dbg(&client->dev,
"%s: secs=%d, mins=%d, hours=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour);
buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
buf[CCR_MIN] = BIN2BCD(tm->tm_min);
/* set hour and 24hr bit */
buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
/* should we also set the date? */
if (datetoo) {
dev_dbg(&client->dev,
"%s: mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
/* month, 1 - 12 */
buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
/* year, since the rtc epoch*/
buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
buf[CCR_WDAY] = tm->tm_wday & 0x07;
buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
}
/* If writing alarm registers, set compare bits on registers 0-4 */
if (reg_base < X1205_CCR_BASE)
for (i = 0; i <= 4; i++)
buf[i] |= 0x80;
/* this sequence is required to unlock the chip */
if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer);
return -EIO;
}
if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer);
return -EIO;
}
/* write register's data */
if (datetoo)
nbytes = 8;
else
nbytes = 3;
for (i = 0; i < nbytes; i++)
rdata[2+i] = buf[i];
xfer = i2c_master_send(client, rdata, nbytes+2);
if (xfer != nbytes+2) {
dev_err(&client->dev,
"%s: result=%d addr=%02x, data=%02x\n",
__func__,
xfer, rdata[1], rdata[2]);
return -EIO;
}
/* If we wrote to the nonvolatile region, wait 10msec for write cycle*/
if (reg_base < X1205_CCR_BASE) {
unsigned char al0e[3] = { 0, X1205_REG_INT, 0 };
msleep(10);
/* ...and set or clear the AL0E bit in the INT register */
/* Need to set RWEL again as the write has cleared it */
xfer = i2c_master_send(client, rwel, 3);
if (xfer != 3) {
dev_err(&client->dev,
"%s: aloe rwel - %d\n",
__func__,
xfer);
return -EIO;
}
if (alm_enable)
al0e[2] = X1205_INT_AL0E;
xfer = i2c_master_send(client, al0e, 3);
if (xfer != 3) {
dev_err(&client->dev,
"%s: al0e - %d\n",
__func__,
xfer);
return -EIO;
}
/* and wait 10msec again for this write to complete */
msleep(10);
}
/* disable further writes */
if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer);
return -EIO;
}
return 0;
}
static int x1205_fix_osc(struct i2c_client *client)
{
int err;
struct rtc_time tm;
tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE, 0);
if (err < 0)
dev_err(&client->dev, "unable to restart the oscillator\n");
return err;
}
static int x1205_get_dtrim(struct i2c_client *client, int *trim)
{
unsigned char dtr;
static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
struct i2c_msg msgs[] = {
{ client->addr, 0, 2, dtr_addr }, /* setup read ptr */
{ client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */
};
/* read dtr register */
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr);
*trim = 0;
if (dtr & X1205_DTR_DTR0)
*trim += 20;
if (dtr & X1205_DTR_DTR1)
*trim += 10;
if (dtr & X1205_DTR_DTR2)
*trim = -*trim;
return 0;
}
static int x1205_get_atrim(struct i2c_client *client, int *trim)
{
s8 atr;
static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
struct i2c_msg msgs[] = {
{ client->addr, 0, 2, atr_addr }, /* setup read ptr */
{ client->addr, I2C_M_RD, 1, &atr }, /* read atr */
};
/* read atr register */
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr);
/* atr is a two's complement value on 6 bits,
* perform sign extension. The formula is
* Catr = (atr * 0.25pF) + 11.00pF.
*/
if (atr & 0x20)
atr |= 0xC0;
dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);
*trim = (atr * 250) + 11000;
dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim);
return 0;
}
struct x1205_limit
{
unsigned char reg, mask, min, max;
};
static int x1205_validate_client(struct i2c_client *client)
{
int i, xfer;
/* Probe array. We will read the register at the specified
* address and check if the given bits are zero.
*/
static const unsigned char probe_zero_pattern[] = {
/* register, mask */
X1205_REG_SR, 0x18,
X1205_REG_DTR, 0xF8,
X1205_REG_ATR, 0xC0,
X1205_REG_INT, 0x18,
X1205_REG_0, 0xFF,
};
static const struct x1205_limit probe_limits_pattern[] = {
/* register, mask, min, max */
{ X1205_REG_Y2K, 0xFF, 19, 20 },
{ X1205_REG_DW, 0xFF, 0, 6 },
{ X1205_REG_YR, 0xFF, 0, 99 },
{ X1205_REG_MO, 0xFF, 0, 12 },
{ X1205_REG_DT, 0xFF, 0, 31 },
{ X1205_REG_HR, 0x7F, 0, 23 },
{ X1205_REG_MN, 0xFF, 0, 59 },
{ X1205_REG_SC, 0xFF, 0, 59 },
{ X1205_REG_Y2K1, 0xFF, 19, 20 },
{ X1205_REG_Y2K0, 0xFF, 19, 20 },
};
/* check that registers have bits a 0 where expected */
for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
unsigned char buf;
unsigned char addr[2] = { 0, probe_zero_pattern[i] };
struct i2c_msg msgs[2] = {
{ client->addr, 0, 2, addr },
{ client->addr, I2C_M_RD, 1, &buf },
};
if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
dev_err(&client->dev,
"%s: could not read register %x\n",
__func__, probe_zero_pattern[i]);
return -EIO;
}
if ((buf & probe_zero_pattern[i+1]) != 0) {
dev_err(&client->dev,
"%s: register=%02x, zero pattern=%d, value=%x\n",
__func__, probe_zero_pattern[i], i, buf);
return -ENODEV;
}
}
/* check limits (only registers with bcd values) */
for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
unsigned char reg, value;
unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
struct i2c_msg msgs[2] = {
{ client->addr, 0, 2, addr },
{ client->addr, I2C_M_RD, 1, &reg },
};
if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
dev_err(&client->dev,
"%s: could not read register %x\n",
__func__, probe_limits_pattern[i].reg);
return -EIO;
}
value = BCD2BIN(reg & probe_limits_pattern[i].mask);
if (value > probe_limits_pattern[i].max ||
value < probe_limits_pattern[i].min) {
dev_dbg(&client->dev,
"%s: register=%x, lim pattern=%d, value=%d\n",
__func__, probe_limits_pattern[i].reg,
i, value);
return -ENODEV;
}
}
return 0;
}
static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
int err;
unsigned char intreg, status;
static unsigned char int_addr[2] = { 0, X1205_REG_INT };
struct i2c_client *client = to_i2c_client(dev);
struct i2c_msg msgs[] = {
{ client->addr, 0, 2, int_addr }, /* setup read ptr */
{ client->addr, I2C_M_RD, 1, &intreg }, /* read INT register */
};
/* read interrupt register and status register */
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
err = x1205_get_status(client, &status);
if (err == 0) {
alrm->pending = (status & X1205_SR_AL0) ? 1 : 0;
alrm->enabled = (intreg & X1205_INT_AL0E) ? 1 : 0;
err = x1205_get_datetime(client, &alrm->time, X1205_ALM0_BASE);
}
return err;
}
static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
return x1205_set_datetime(to_i2c_client(dev),
&alrm->time, 1, X1205_ALM0_BASE, alrm->enabled);
}
static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return x1205_get_datetime(to_i2c_client(dev),
tm, X1205_CCR_BASE);
}
static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return x1205_set_datetime(to_i2c_client(dev),
tm, 1, X1205_CCR_BASE, 0);
}
static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
{
int err, dtrim, atrim;
if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
atrim / 1000, atrim % 1000);
return 0;
}
static const struct rtc_class_ops x1205_rtc_ops = {
.proc = x1205_rtc_proc,
.read_time = x1205_rtc_read_time,
.set_time = x1205_rtc_set_time,
.read_alarm = x1205_rtc_read_alarm,
.set_alarm = x1205_rtc_set_alarm,
};
static ssize_t x1205_sysfs_show_atrim(struct device *dev,
struct device_attribute *attr, char *buf)
{
int err, atrim;
err = x1205_get_atrim(to_i2c_client(dev), &atrim);
if (err)
return err;
return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
}
static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
struct device_attribute *attr, char *buf)
{
int err, dtrim;
err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
if (err)
return err;
return sprintf(buf, "%d ppm\n", dtrim);
}
static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
static int x1205_sysfs_register(struct device *dev)
{
int err;
err = device_create_file(dev, &dev_attr_atrim);
if (err)
return err;
err = device_create_file(dev, &dev_attr_dtrim);
if (err)
device_remove_file(dev, &dev_attr_atrim);
return err;
}
static void x1205_sysfs_unregister(struct device *dev)
{
device_remove_file(dev, &dev_attr_atrim);
device_remove_file(dev, &dev_attr_dtrim);
}
static int x1205_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int err = 0;
unsigned char sr;
struct rtc_device *rtc;
dev_dbg(&client->dev, "%s\n", __func__);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
if (x1205_validate_client(client) < 0)
return -ENODEV;
dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
&x1205_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
i2c_set_clientdata(client, rtc);
/* Check for power failures and eventualy enable the osc */
if ((err = x1205_get_status(client, &sr)) == 0) {
if (sr & X1205_SR_RTCF) {
dev_err(&client->dev,
"power failure detected, "
"please set the clock\n");
udelay(50);
x1205_fix_osc(client);
}
}
else
dev_err(&client->dev, "couldn't read status\n");
err = x1205_sysfs_register(&client->dev);
if (err)
goto exit_devreg;
return 0;
exit_devreg:
rtc_device_unregister(rtc);
return err;
}
static int x1205_remove(struct i2c_client *client)
{
struct rtc_device *rtc = i2c_get_clientdata(client);
rtc_device_unregister(rtc);
x1205_sysfs_unregister(&client->dev);
return 0;
}
static const struct i2c_device_id x1205_id[] = {
{ "x1205", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, x1205_id);
static struct i2c_driver x1205_driver = {
.driver = {
.name = "rtc-x1205",
},
.probe = x1205_probe,
.remove = x1205_remove,
.id_table = x1205_id,
};
static int __init x1205_init(void)
{
return i2c_add_driver(&x1205_driver);
}
static void __exit x1205_exit(void)
{
i2c_del_driver(&x1205_driver);
}
MODULE_AUTHOR(
"Karen Spearel <kas111 at gmail dot com>, "
"Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
module_init(x1205_init);
module_exit(x1205_exit);
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