[Bug 223642] ds3231 iic driver can't initialise a new device

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=223642

            Bug ID: 223642
           Summary: ds3231 iic driver can't initialise a new device
           Product: Base System
           Version: 11.1-STABLE
          Hardware: arm
                OS: Any
            Status: New
          Severity: Affects Only Me
          Priority: ---
         Component: arm
          Assignee: freebsd-arm at FreeBSD.org
          Reporter: bscott at bunyatech.com.au

Created attachment 187954
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=187954&action=edit
Patch to change failures to start the oscillator and acknowledge interrupts to
be warnings

During initialisation of the ds3231 rtc driver it attempts to enable the
oscillator and acknowledge any alarm conditions.
For a brand new, never powered device this is rejected until the time has been
set, however because these calls fail the device isn't started and the time is
never set.

Writing a quick and dirty program based on the i2c utility I have initialised
the device without using the driver. When loaded, the driver proceeds normally
and uses the device as intended.
I have patched the driver (sys/dev/iicbus/ds3231.c) to just warn on failures of
the two calls mentioned earlier.

I haven't found any way to return one of the chips back to pristine condition.

Fortunately I had another device that I had purchased but never used that I
could use to test the change with and had the device accepted properly (with a
few extra warning messages on first boot).

It's quite possible that other suppliers actually test these devices before
selling them and that normally they have some time setting when first
installed. Mine where $2 each from Malaysia with free shipping so I couldn't
really expect much. I don't know if other people would experience the same
problem.

While debugging this, I have also noticed that the device is initialised with a
zero based day of week (i.e. 0-6) but the specification for the device is for a
value from 1 to 7. The value returned by the device is never used so this
shouldn't matter unless some version of the chip in the future enforces the
specification for some reason.

-- 
You are receiving this mail because:
You are the assignee for the bug.