Re: I2C RTC causes boot delay...

Joakim Tjernlund schrieb:

quoted

I wrote,

quoted

I have an I2C RTC connected to my MPC855T to substitute the internal one.

I noticed that between

  Verifying Checksum ... OK
  Uncompressing Kernel Image ... OK

and the next lines printed while booting "nothing" happens for THREE
seconds.

I reckon that is has something to do with not having an external 32kHz
clock on the MPC. But I can't find the place in the sources!

I migth have found it:

Is it ok and enough to set

        ppc_md.set_rtc_time             = NULL;
        ppc_md.get_rtc_time             = NULL;

in platform_init()? And then later - when I2C is initialized - set it
to the appropriate I2C RTC functions?

Yes, that's it. If your kernel ever hangs after printing out
"calibrating delay loop ...", try adding a set_tb(0,0) somewhere in m8xx_setup.c,
to see if it fixes it.

Thanks Jocke!

You may also want to add an "I2C reset sequence" in your firmware/kernel
if your I2C clock gets stuck and don't respond(can happen if reset/power down while
reading the RTC). Look in u-boot for details.

Yeah. I know. I should put into PPCBoot/U-Boot.
But in the docs it says it's only for SOFT_I2C aka bitbang!
So
a) can I toggle the pins using GPIO and still use HARD_I2C? or
b) can I use SOFT_I2C in PPCBoot and CPM I2C (8xx-algo) under linux?

Steven


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