On Monday 22 June 2009, Paulraj, Sandeep wrote: > The DM365 EVM does not have a battery so when on resetting the > EVM by doing a power reset you lose the date and time information.
The registers were lost *without* a power reset. That is, with either (a) "reboot" from command line, or (b) pressing the "reset" button. No loss of power. That's why I was surprised: no loss of power, but the RTC acted as if there were one. Chapter 10 of the ARM guide (SPRUFG5) says PRTCSS has only a power-on-reset -- PWRST is the signal, from a tps65510 chip on the EVM, which is not going to be issued except on board power-up without a backup battery (or presumably, with a dead battery). Would having PERI_CLKCTL.PRTCSSCLKS set wrong matter? Or is the RTC probe() maybe resetting things? > You need a battery backup running for the date and time info to > be saved. Date and time info are erased on power reset. If you're saying that normal no-power-loss resets also cause RTC re-init, maybe because the chip or board is designed to act that way, it's worth mentioning that surprise in the driver's Kconfig entry. - Dave > Without the battery and mains, > no information is retained and all registers, including RTC_SEC, > RTC_MIN , RTC_HOUR , RTC_DAY0 and RTC_DAY1 which store date and > time info are reset to default values. > > You are seeing January 1, 2000 because the driver initializes > it to that value > > > > -----Original Message----- > > From: David Brownell [mailto:[email protected]] > > Sent: Sunday, June 21, 2009 8:50 PM > > To: [email protected] > > Cc: Paulraj, Sandeep > > Subject: Re: [RFC][PATCH] DM365 RTC Support > > > > This RTC resets to January 1, 2000 when I reboot. > > > > How to stop that behavior? > > > > > > _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
