Hi Jonathan,
Am 08.07.24 um 01:08 schrieb Jonathan Neuschäfer:
Raspberry Pi boards have a "revision code", documented here:
https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#new-style-revision-codes
AFAIK these revision codes mostly refer to the board and not to the CPU.
The abuse of /proc/cpuinfo has been rejected in the past and from my
understanding this applies also in this case.
This patch copies what the downstream kernel does and reads it from the
devicetree property /system/linux,revision. This enables some software
to work as intended on mainline kernels:
https://github.com/hzeller/rpi-rgb-led-matrix/blob/a3eea997a9254b83ab2de97ae80d83588f696387/lib/gpio.cc#L247
This is a bad example because the application doesn't really care about
the kernel and directly access the hardware registers via /dev/mem. A
proper application would use the dedicated userspace API (GPIO Character
Device or PWM). I would bet that the application does not work with the
Raspberry Pi 5.
Regards
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@xxxxxxx>
---
Jonathan Neuschäfer (2):
dt-bindings: arm: bcm2835: Specify /system/linux,revision property
ARM: bcm2835: Detect system revision
Documentation/devicetree/bindings/arm/bcm/bcm2835.yaml | 12 ++++++++++++
arch/arm/mach-bcm/board_bcm2835.c | 11 +++++++++++
2 files changed, 23 insertions(+)
---
base-commit: 22a40d14b572deb80c0648557f4bd502d7e83826
change-id: 20240707-raspi-revision-84dffdfaebce
Best regards,
--
Jonathan Neuschäfer <j.neuschaefer@xxxxxxx>
