[PATCH v2 4/4] riscv: dts: starfive: jh7110: Add the RTC node

[Owen O'Hehir]

Hi E,

> Is status property applicable to SoC rtc? If not, then is 'rtc' label
> appropriate when there's no status applicable?

The RTC is in the SoC always-on domain and its clocks come from aoncrg;
the 32 kHz oscillator is set in jh7110-common.dtsi, which every JH7110
board includes, so no board needs to enable it. It is left enabled in
the dtsi like the other always-on nodes (aoncrg, aongpio, pwrc). Other
SoC RTCs do the same, e.g. Allwinner (including the D1), Sophgo CV180x
and i.MX snvs_rtc; the ones disabled by default, such as STM32, depend
on board parts that not every board has.

An alias is only needed when a board has more than one RTC, and none of
the JH7110 boards in the tree do. A board can still disable the node or
alias it through the label.

> Note that Mars CM / CM-Lite System-on-Modules may be used commonly with
> board carriers which implement a battery-backed RTC on the I2C bus, and
> so another 'rtc' label may be applicable, something to consider.

Good point. v3 renames the label to soc_rtc, leaving rtc free for a
carrier board's RTC.


Owen