On 16/11/2019 12:46:20+0100, Kars de Jong wrote: > The msm6242_set()/msm6242_clear() functions are used when writing to Control > Register D to set or clear the HOLD bit when reading the current time from > the RTC. > > Doing this with a read-modify-write cycle will potentially clear an > interrupt condition which occurs between the read and the write. > > The datasheet states the following about this: > > When writing the HOLD or 30 second adjust bits of register D, it is > necessary to write the IRQ FLAG bit to a "1". > > Since the only other bits in the register are the 30 second adjust bit > (which is not used) and the BUSY bit (which is read-only), the > read-modify-write cycle can be replaced by a simple write with the IRQ FLAG > bit set to 1 and the other bits (except HOLD) set to 0. > > Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Tested-by: Kars de Jong <jongk@xxxxxxxxxxxxxx> > Signed-off-by: Kars de Jong <jongk@xxxxxxxxxxxxxx> > --- > drivers/rtc/rtc-msm6242.c | 20 ++++---------------- > 1 file changed, 4 insertions(+), 16 deletions(-) > Applied, thanks. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
