UP2 SPI

Rostislav Spinar

Hello,

...
[ 4.736416] spidev spi-SPT0001:00: do not use this driver in production systems!
[ 4.739434] spidev spi-SPT0001:01: do not use this driver in production systems!
...

Could we get more information about this?

Regards
Rostislav

WereCatf

It's not an actual error-message, it's just that some kernel-developer doesn't like the idea of SPI being useable from userspace and thus doesn't want people using that driver, so he/she/it added that line there. Nothing more. Ignore it.

Dan O'Donovan

There's a little bit of info about it here:
https://patchwork.kernel.org/patch/9212219/

Leading up to this, there was some debates with the kernel maintainer which shed some light on it:
https://patchwork.kernel.org/patch/6113191/

My interpretation is that, basically, the warning is just there as an advisory note to make it clear that the kernel isn't loading a driver that has been specifically crafted for the peripheral device that is present on the SPI bus, and cannot give any guarantees by itself that the device will function correctly when this driver is loaded (because this is left up to the user-space "driver" that accesses it via spidev). From the kernel point-of-view, the preference would be to avoid the ambiguity of matching a generic device to a generic driver, and implement something device-specific instead to ensure that drivers and devices are properly matched.

But this doesn't mean that your user-space driver won't work, or that spidev isn't appropriate for using with your device. It just means, in my view, that the kernel can't give any guarantees about it.