arm64: dts: allwinner: Add sun4i MMIO timer nodes
authorSamuel Holland <samuel@sholland.org>
Mon, 22 Mar 2021 04:47:06 +0000 (23:47 -0500)
committerMaxime Ripard <maxime@cerno.tech>
Tue, 11 May 2021 08:17:51 +0000 (10:17 +0200)
commit12bcaacaff49fc18612a7df21b76235ca8eb5c7f
tree2e4f6112c55629229e9eaf3cdc9420bd563b845a
parentaf97dd5559c59050f452997a4328b1a794f6fd6a
arm64: dts: allwinner: Add sun4i MMIO timer nodes

For a CPU to enter an idle state, some timer must be available to
trigger an IRQ and wake it back up. The local ARM architectural timer is
not sufficient, because that timer stops when the CPU is powered down.
The ARM architectural timer from some other CPU can be used, but doing
so prevents that other CPU from entering an idle state. For all CPUs to
power down at the same time, Linux needs a timer which is not tied to
any CPU.

Hook up the "sun4i" timer so it can be used for this purpose. It runs at
24 MHz, which balances resolution and power consumption.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210322044707.19479-5-samuel@sholland.org
arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi