-sh-4.4# insmod rtc-m41t93.ko
[ 3447.986508] rtc-m41t93 spi0.0: jin test2 read secs=0, mins=0, hours=0, mday=0, mon=-1, year=100, wday=-1
[ 3447.996096] rtc-m41t93 spi0.0: jin test ret=0
[ 3448.000948] rtc-m41t93 spi0.0: rtc core: registered rtc-m41t93 as rtc0
[ 3448.007772] rtc-m41t93 spi0.0: jin test3 probe
-sh-4.4# date --set="20201015 14:32"
Thu Oct 15 14:32:00 -05 2020
-sh-4.4# hwclock --systohc --utc
[ 3600.903392] rtc-m41t93 spi0.0: jin test1 write secs=17, mins=32, hours=19, mday=15, mon=9, year=120, wday=4
-sh-4.4# [ 3600.959304] rtc-m41t93 spi0.0: jin test2 read secs=0, mins=0, hours=0, mday=0, mon=-1, year=100, wday=-1
[ 3600.973839] rtc-m41t93 spi0.0: jin test ret=0
-sh-4.4# hwclock --systohc --utc
[ 3613.852979] rtc-m41t93 spi0.0: jin test1 write secs=30, mins=32, hours=19, mday=15, mon=9, year=120, wday=4
[ 3613.864034] rtc-m41t93 spi0.0: jin test2 read secs=3, mins=0, hours=10, mday=0, mon=-1, year=100, wday=-1
[ 3613.873731] rtc-m41t93 spi0.0: jin test ret=0
-sh-4.4# hwclock --systohc --utc
[ 3616.232812] rtc-m41t93 spi0.0: jin test1 write secs=32, mins=32, hours=19, mday=15, mon=9, year=120, wday=4
-sh-4.4# [ 3616.244620] rtc-m41t93 spi0.0: jin test2 read secs=0, mins=40, hours=0, mday=0, mon=-1, year=104, wday=-1
[ 3616.254458] rtc-m41t93 spi0.0: jin test ret=0
hwclock --systohc --utc
[ 3625.690010] rtc-m41t93 spi0.0: jin test1 write secs=41, mins=32, hours=19, mday=15, mon=9, year=120, wday=4
-sh-4.4# [ 3625.700937] rtc-m41t93 spi0.0: jin test2 read secs=0, mins=0, hours=0, mday=0, mon=-1, year=100, wday=-1
[ 3625.711095] rtc-m41t93 spi0.0: jin test ret=0
-sh-4.4# hwclock -r
[ 3660.309908] rtc-m41t93 spi0.0: jin test2 read secs=0, mins=4, hours=0, mday=0, mon=9, year=100, wday=2
[ 3660.319503] rtc-m41t93 spi0.0: jin test ret=0
hwclock: RTC_RD_TIME: Invalid argument
-sh-4.4# hwclock --systohc --utc
[ 3868.465926] rtc-m41t93 spi0.0: jin test1 write secs=44, mins=36, hours=19, mday=15, mon=9, year=120, wday=4
-sh-4.4# [ 3868.477142] rtc-m41t93 spi0.0: jin test2 read secs=0, mins=0, hours=0, mday=40, mon=-1, year=340, wday=-1
[ 3868.487247] rtc-m41t93 spi0.0: jin test ret=0
-sh-4.4# date
Thu Oct 15 14:36:49 -05 2020
39: 51 0 0 0 GPC-PSCI 31 Edge 30820000.ecspi
-sh-4.4# hwclock -w
[ 431.303151] rtc-m41t93 spi0.0: jin test write secs=40, mins=13, hours=13, mday=28, mon=8, year=120, wday=1
-sh-4.4# [ 431.314511] rtc-m41t93 spi0.0: jin test read secs=0, mins=0, hours=0, mday=0, mon=-1, year=100, wday=-1
[ 431.324597] rtc-m41t93 spi0.0: jin test ret=0
-sh-4.4# cat /proc/interrupts | grep spi
39: 84 0 0 0 GPC-PSCI 31 Edge 30820000.ecspi
-sh-4.4# hwclock -r
[ 442.794300] rtc-m41t93 spi0.0: jin test read secs=80, mins=0, hours=0, mday=40, mon=-1, year=200, wday=-1
[ 442.803954] rtc-m41t93 spi0.0: jin test ret=0
hwclock: RTC_RD_TIME: Invalid argument
-sh-4.4#
-sh-4.4# cat /proc/interrupts | grep spi