Commit d54e8259 authored by Philippe Gerum's avatar Philippe Gerum Committed by Dmitriy Cherkasov

arm64: dts: bcm2837: provide for BT-less variant, re-enabling uart0 as serial

Raspberry 3 has two UARTs: uart0 is a full-fledged pl011 used for BT
by default, uart1 is a poor-man's low throughput serial device dubbed
as the "mini-uart". Unfortunately, uart1 is a massive pain, whose
clock rate is based on the CPU clock rate: this makes it quite
unstable as a serial console when a CPU frequency governor is enabled.

When BT is useless, we'd rather switch uart0 from BT to the serial
pins, disabling uart1 in the same move, so that we recover a decent
console device (*) with a stable clocking.

bcm2837-rpi-3-b-nobt.dtb is a fixed up blob doing exactly that.

(*) cmdline should mention console=ttyAMA0,<speed>
parent b78aefb2
# SPDX-License-Identifier: GPL-2.0
dtb-$(CONFIG_ARCH_BCM2835) += bcm2837-rpi-3-b.dtb
dtb-$(CONFIG_ARCH_BCM2835) += bcm2837-rpi-3-b.dtb bcm2837-rpi-3-b-nobt.dtb
dts-dirs += northstar2
dts-dirs += stingray
......
/dts-v1/;
#include "bcm2837-rpi-3-b.dts"
&uart0 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&uart0_gpio32>;
};
&uart1 {
status = "disabled";
};
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