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由 Michael Hamel 提交于
I have discovered that the current version of rtc-x1205.c does not work correctly when asked to set the alarm time by the RTC_WKALM_SET ioctl() call. This happens because the alarm registers do not behave like the current-time registers. They are non-volatile. Two things go wrong: - the X1205 requires a 10 msec delay after any attempt to write to the non-volatile registers. The x1205_set_datetime() routine does the write as 8 single-byte writes without any delay. Only the first write succeeds. The second is NAKed because the chip is busy. - the X1205 resets the RWEL bit after any write to the non-volatile registers. This would lock out any further writes after the first even with a 10msec delay. I fix this by doing a single 8-byte write and then waiting 10msec for the chip to be ready. A side effect of this change is that it will speed up x1205_rtc_set_time() which uses the same code. I have also implemented the 'enable' bit in the rtc_wkalm structure, which the existing driver does not attempt to do. I have modified both x1205_rtc_set_alarm() to set the AL0E bit, and x1205_rtc_read_alarm() to return it. I have tested this patch on a LinkSys NSLU2 under OpenWRT, but on no other hardware. On the NSLU2 the X1205 correctly asserts its IRQ pin when the alarm time matches the current time. [akpm@linux-foundation.org: clean up over-parenthesisation] Signed-off-by: NMichael Hamel <mhamel@adi.co.nz> Signed-off-by: NAlessandro Zummo <a.zummo@towertech.it> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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