[Toybox] [PATCH] Add i2ctransfer.

[Rob Landley]

On 7/6/23 18:23, enh via Toybox wrote:
> Tested on a Raspberry Pi 400 with a BME680 connected to the relevant
> pins, and commands like `i2ctransfer 1 w3 at 0x77 0x60 0xb6 0xd0 r1`, which
> writes 0xb6 to register 0x60 of chip 0x77 on bus 1, and then reads one
> byte.

I broke down and did a cleanup pass (f90b2994a2da) which compiles but I can't
test it. Did I break anything obvious?

I still need an i2c test environment. QEMU says it can emulate pi2b and pi3b
(although whether this includes i2c I dunno), but according to
https://raspberrypi.stackexchange.com/questions/127537/can-i-use-the-mainline-kernel-in-my-rasp-if-not-why
the relevant defconfigs are bcm2709_defconfig and either bcmrpi3_defconfig or
bcm2711_defconfig but all the vanilla 6.4 kernel has is bcm2835_defconfig.

Flashbacks to the last time I tried to make this work: none of it's in vanilla,
and even if you try to use qemu -kernel to bypass the weird bootloader and init
stuff, it's still off in a fork. :(

Hmmm, maybe https://gist.github.com/jonte/b4bd83a5f2e8330418b1f3322bff74f2 is
useful in a mkroot testing context...

Rob