Commit 471d47e3 authored by Michael Hamel's avatar Michael Hamel Committed by Linus Torvalds

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: default avatarMichael Hamel <mhamel@adi.co.nz>
Signed-off-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7a36a752
......@@ -71,6 +71,7 @@
#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
......@@ -78,6 +79,8 @@
#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;
/*
......@@ -89,8 +92,8 @@ 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 */
......@@ -98,7 +101,7 @@ static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
};
/* read date registers */
if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
......@@ -110,6 +113,11 @@ static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
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 */
......@@ -138,7 +146,7 @@ static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
};
/* read status register */
if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
......@@ -147,10 +155,11 @@ static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
}
static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
int datetoo, u8 reg_base)
int datetoo, u8 reg_base, unsigned char alm_enable)
{
int i, xfer;
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 };
......@@ -189,6 +198,11 @@ static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
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);
......@@ -200,19 +214,57 @@ static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
return -EIO;
}
/* write register's data */
for (i = 0; i < (datetoo ? 8 : 3); i++) {
unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
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);
xfer = i2c_master_send(client, rdata, 3);
/* ...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: xfer=%d addr=%02x, data=%02x\n",
"%s: aloe rwel - %d\n",
__func__,
xfer, rdata[1], rdata[2]);
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) {
......@@ -230,9 +282,9 @@ static int x1205_fix_osc(struct i2c_client *client)
tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
dev_err(&client->dev,
"unable to restart the oscillator\n");
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;
}
......@@ -248,7 +300,7 @@ static int x1205_get_dtrim(struct i2c_client *client, int *trim)
};
/* read dtr register */
if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
......@@ -280,7 +332,7 @@ static int x1205_get_atrim(struct i2c_client *client, int *trim)
};
/* read atr register */
if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
......@@ -403,14 +455,33 @@ static int x1205_validate_client(struct i2c_client *client)
static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
return x1205_get_datetime(to_i2c_client(dev),
&alrm->time, X1205_ALM0_BASE);
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->time, 1, X1205_ALM0_BASE, alrm->enabled);
}
static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
......@@ -422,7 +493,7 @@ static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
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);
tm, 1, X1205_CCR_BASE, 0);
}
static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
......
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