Guys:
I have an embedded computer that has a DS1307 on it. I wrote an i2c
adapter for the board, and now it appears to find the chip:
..
i2c-core.o: i2c core module
i2c-dev.o: i2c /dev entries driver module
i2c-core.o: driver i2c-dev dummy driver registered.
i2c-algo-bit.o: i2c bit algorithm module
i2c_xxx_init: builtin i2c bus adapter <bgat at billgatliff.com>
i2c-dev.o: Registered 'xxx-i2c' as minor 0
i2c-core.o: adapter xxx-i2c registered as adapter 0.
i2c-proc.o version 2.6.1 (20010825)
..
i2c-core.o: driver ds1307 registered.
i2c-core.o: client [ds1307] registered to adapter [xxx-i2c](pos. 0).
Dallas Semiconductor DS1307 Real-Time Clock driver (V0.03)
i2c-core.o: driver fs6377 registered.
i2c-core.o: client [fs6377] registered to adapter [xxx-i2c](pos. 1).
fs6377_set_register(fs6377.c:101): WARNING: skipping register initialization
AMI FS6377 Programmable PLL driver $Revision: 1.4 $ <bgat at billgatliff.com>
..
(I also wrote the fs6377 driver).
Trouble is, I can't figure out how I'm supposed to access the ds1307
from kernel code. My goal is to use the ds1307 as the system's
realtime clock, which means I have to "hook" it to /dev/rtc and/or
/proc/driver/rtc.
My current attempt looks like this:
static unsigned long xxx_rtc_get_time (void)
{
struct i2c_client *c;
struct ds1307_date d;
int i;
c = i2c_get_client(I2C_DRIVERID_DS1307, 0, 0);
if (c)
{
if (!i2c_use_client(c))
{
i = ds1307_getdate(c, &d);
i2c_release_client(c);
return mktime(d.tm_year, d.tm_mon, d.tm_mday,
d.tm_hour, d.tm_min, d.tm_sec);
}
else printk("%s: error: i2c client already in use!\n", __FUNCTION__);
}
else printk("%s: error: couldn't get i2c client handle!\n", __FUNCTION__);
return mktime(2000, 1, 1, 0, 0, 0);
}
But I'm pretty sure that isn't what you had in mind. :^)
I had to make ds1370_getdate() nonstatic to do this. I have also
noticed that the results returned by ds1307_getdate() aren't right---
the time doesn't change. (But since the ds1307 i2c driver can "see"
the chip, the i2c adapter code must be right, no?)
What's the right way to go about communicating with a ds1307 i2c
device from inside the kernel? I could really use an example or two.
Thanks!
b.g.
--
Bill Gatliff
http://billgatliff.com
