[linuxsh-dev] [PATCH:] Enhanced RTC Support

[NIIBE Y. <gn...@m1...>]

SUGIOKA Toshinobu wrote:
 > This patch implements 'Enhanced RTC Support' by emulating
 > MC146868 with CMOS_READ/CMOS_WRITE macros.
 > However, drivers/char/rtc.c should be modified slightly,
 > since emulation is incomplete.
 > 
 > 'hwclock' command now works on my board(SH7709A) with this patch.

Great.  Looks good.

I just am afraid of there's need to support real MC146868 in some
cases.  Say, Hitachi Solution Engine has another RTC.

Besides, I think that we only could change the function
rtc_is_updating.

 > Index: drivers/char/rtc.c
 > ===================================================================
[...]
 > +#ifdef __sh__
 > +	do {
 > +	ctrl_outb((ctrl_inb(RCR1) & (RCR1_CIE | RCR1_AIE)) | RCR1_AF, RCR1); /*
 > Clear CF */
 > +#else
 >  	if (rtc_is_updating() != 0)
 >  		while (jiffies - uip_watchdog < 2*HZ/100)
 >  			barrier();
 > +#endif
 >  
 >  	/*
 >  	 * Only the values that we read from the RTC are set. We leave

I know that this is the way of handling SH's RTC in the manual, but we
could implement rtc_is_updating, such as checking R64CNT is near 0 or
not (with some safety).  Errr... well, the implementation depends on
architecture, SH-3 or SH-4.
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