[i2c] [PATCH] DS1339: oscillator code added.
David Brownell
david-b at pacbell.net
Mon Jun 25 19:40:31 CEST 2007
On Tuesday 19 June 2007, Rodolfo Giometti wrote:
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -292,10 +292,12 @@ static int __devinit ds1307_probe(struct i2c_client *client)
> /* oscillator is off; need to turn it on */
> if ((ds1307->regs[0] & DS1337_BIT_nEOSC)
> || (ds1307->regs[1] & DS1337_BIT_OSF)) {
> -no_osc_start:
> - printk(KERN_ERR "no %s oscillator code\n",
> - chip->name);
> - goto exit_free;
> + dev_info(&client->dev,
> + "oscillator is off. Turned on!\n");
> + i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
> + ds1307->regs[0] & ~DS1337_BIT_nEOSC);
Docs don't couple nEOSC with OSF that tightly though...
> + i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
> + ds1307->regs[1] & ~DS1337_BIT_OSF);
... because OSF can be set (and thus need a warning) even
if the oscillator got started again, or didn't stop. For
example, first time powerup, Vcc too low, noise.
> }
> break;
> default:
> @@ -331,7 +333,9 @@ read_rtc:
> case ds_1340:
> /* FIXME write code to start the oscillator */
> if (tmp & DS1307_BIT_CH)
> - goto no_osc_start;
> + printk(KERN_ERR "no %s oscillator code\n",
> + chip->name);
> + goto exit_free;
Notice that this is missing brackets, and thus would prevent
a ds1340 from *ever* working ...
> break;
> default:
> break;
Try the appended patch instead. Not only does it fix those bugs,
but it handles DS1338 and DS1340 oscillator issues better too.
- Dave
============ CUT HERE
From: Rodolfo Giometti <giometti at enneenne.com>
When we find a ds1337 or ds1339 with the oscillator powered off,
turn it on; and if the oscillator fault flag was set, clear it
and warn that the clock needs to be set.
Signed-off-by: Rodolfo Giometti <giometti at linux.it>
Bugfixes; provide corresponding update for DS1338. Use a common
warning message ("SET TIME!") whenever the clock needs to be set
after oscillator fault (or enable, if that's not separate status).
Signed-off-by: David Brownell <dbrownell at users.sourceforge.net>
---
Applies on top of the ds1307 cleanup patch that's now in MM.
drivers/rtc/rtc-ds1307.c | 55 ++++++++++++++++++++++++++++++-----------------
1 file changed, 36 insertions(+), 19 deletions(-)
--- at91.orig/drivers/rtc/rtc-ds1307.c 2007-06-25 09:56:11.000000000 -0700
+++ at91/drivers/rtc/rtc-ds1307.c 2007-06-25 10:26:43.000000000 -0700
@@ -52,6 +52,7 @@ I2C_CLIENT_INSMOD;
/* RTC registers don't differ much, except for the century flag */
#define DS1307_REG_SECS 0x00 /* 00-59 */
# define DS1307_BIT_CH 0x80
+# define DS1340_BIT_nEOSC 0x80
#define DS1307_REG_MIN 0x01 /* 00-59 */
#define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
# define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */
@@ -68,7 +69,7 @@ I2C_CLIENT_INSMOD;
*/
#define DS1307_REG_CONTROL 0x07 /* or ds1338 */
# define DS1307_BIT_OUT 0x80
-# define DS1338_BIT_STOP 0x20
+# define DS1338_BIT_OSF 0x20
# define DS1307_BIT_SQWE 0x10
# define DS1307_BIT_RS1 0x02
# define DS1307_BIT_RS0 0x01
@@ -84,8 +85,8 @@ I2C_CLIENT_INSMOD;
# define DS1340_BIT_FT 0x40
# define DS1340_BIT_CALIB_SIGN 0x20
# define DS1340_M_CALIBRATION 0x1f
-#define DS1338_REG_FLAG 0x09
-# define DS1338_BIT_OSF 0x80
+#define DS1340_REG_FLAG 0x09
+# define DS1340_BIT_OSF 0x80
#define DS1337_REG_STATUS 0x0f
# define DS1337_BIT_OSF 0x80
# define DS1337_BIT_A2I 0x02
@@ -296,11 +297,10 @@ ds1307_detect(struct i2c_adapter *adapte
switch (ds1307->type) {
case ds_1337:
case ds_1339:
- ds1307->type = ds_1337;
-
ds1307->reg_addr = DS1337_REG_CONTROL;
ds1307->msg[1].len = 2;
+ /* get registers that the "rtc" read below won't read... */
tmp = i2c_transfer(adapter, ds1307->msg, 2);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
@@ -311,13 +311,16 @@ ds1307_detect(struct i2c_adapter *adapte
ds1307->reg_addr = 0;
ds1307->msg[1].len = sizeof(ds1307->regs);
- /* oscillator is off; need to turn it on */
- if ((ds1307->regs[0] & DS1337_BIT_nEOSC)
- || (ds1307->regs[1] & DS1337_BIT_OSF)) {
-no_osc_start:
- printk(KERN_ERR "no %s oscillator code\n",
- chip->name);
- goto exit_free;
+ /* oscillator off? turn it on, so clock can tick. */
+ if (ds1307->regs[0] & DS1337_BIT_nEOSC)
+ i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
+ ds1307->regs[0] & ~DS1337_BIT_nEOSC);
+
+ /* oscillator fault? clear flag, and warn */
+ if (ds1307->regs[1] & DS1337_BIT_OSF) {
+ i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
+ ds1307->regs[1] & ~DS1337_BIT_OSF);
+ dev_warn(&client->dev, "SET TIME!\n");
}
break;
default:
@@ -340,20 +343,33 @@ read_rtc:
*/
tmp = ds1307->regs[DS1307_REG_SECS];
switch (ds1307->type) {
+ case ds_1340:
+ /* FIXME read register with DS1340_BIT_OSF, use that to
+ * trigger the "set time" warning (*after* restarting the
+ * oscillator!) instead of this weaker ds1307/m41t00 test.
+ */
case ds_1307:
- case ds_1338:
case m41t00:
+ /* clock halted? turn it on, so clock can tick. */
if (tmp & DS1307_BIT_CH) {
- i2c_smbus_write_byte_data(client, 0, 0);
- dev_warn(&client->dev,
- "oscillator started; SET TIME!\n");
+ i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
+ dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
break;
- case ds_1340:
- /* FIXME write code to start the oscillator */
+ case ds_1338:
+ /* clock halted? turn it on, so clock can tick. */
if (tmp & DS1307_BIT_CH)
- goto no_osc_start;
+ i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
+
+ /* oscillator fault? clear flag, and warn */
+ if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
+ i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
+ ds1307->regs[DS1337_REG_CONTROL]
+ & ~DS1338_BIT_OSF);
+ dev_warn(&client->dev, "SET TIME!\n");
+ goto read_rtc;
+ }
break;
default:
break;
@@ -380,6 +396,7 @@ read_rtc:
*
* REVISIT forcing 24 hour mode can prevent multi-master
* configs from sharing this RTC ... don't do this.
+ * The clock needs to be reset after changing it, too...
*/
tmp = ds1307->regs[DS1307_REG_HOUR];
if (tmp & (1 << 6)) {
More information about the i2c
mailing list