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

drivers/rtc/rtc-x1205.c

+91 −20
Original line number Diff line number Diff line
@@ -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, 3);

		if (xfer != 3) {

	xfer = i2c_master_send(client, rdata, nbytes+2);

	if (xfer != nbytes+2) {

		dev_err(&client->dev,

				"%s: xfer=%d addr=%02x, data=%02x\n",

			"%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) {
@@ -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)