On Sun, 03 May 2020 22:19:35 +0200, Jacko Dirks said:

have never submitted a kernel patch before. So, should I email a mailing list warning everyone of what I want to do? Is there anything else I should know about?

Yes, you should do a bit of Googling and/or check the current source tree to make sure you aren't re-inventing the wheel.. There may already be working or near-working code, A quick Google check foud: Somebody else was looking at the problem back in February. https://www.raspberrypi.org/forums/viewtopic.php?t=265832 http://abyz.me.uk/rpi/pigpio/python.html apparently includes some slave functionality from userspace that may be useful as a guide: I2C/SPI SLAVE bsc_xfer I2C/SPI as slave transfer bsc_i2c I2C as slave transfer

To clarify, this is not about the creation of the driver itself, more of a meta question of how to announce that I want to do this.

Pretty much nobody cares that you *want* to do it. GitHub and SourceForge are full of abandonware where somebody *wanted* to do something and never finished it. Once you have a driver that loads and semi/mostly works, *then* you announce it, usually in the form of a patch stream generated using 'git format-patch' and 'git send-email'. But Greg KH can't even add it to drivers/staging until you have at least a good first pass at workig code...