From 471d47e3223311d2638755717f97dc9a298f6dc9 Mon Sep 17 00:00:00 2001 From: Michael Hamel Date: Fri, 4 Jul 2008 09:59:30 -0700 Subject: [PATCH] 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 Signed-off-by: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-x1205.c | 111 ++++++++++++++++++++++++++++++++-------- 1 file changed, 91 insertions(+), 20 deletions(-) diff --git a/drivers/rtc/rtc-x1205.c b/drivers/rtc/rtc-x1205.c index eaf55945f2..7dcfba1bbf 100644 --- a/drivers/rtc/rtc-x1205.c +++ b/drivers/rtc/rtc-x1205.c @@ -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) -- 2.39.5