Add Sensorless Homing current

[danym21]

Requirements

TMC drivers with stallguard enabled

Description

I use TMC5160 stepper drivers, since I use 0.9deg/step instead 1.8deg/step motors stallguard is not triggered correctly with the the current that I use for printing.

as example for printing I use a current from 1100 mA and "STALL_SENSITIVITY 2" the machine is crashing, when I use "STALL_SENSITIVITY 1" Stallguard is trigger often in the middle of the way to the edge. When I use a current from 462 for homing with "STALL_SENSITIVITY 2" all is working fine but on printing it is losing steps.

Benefits

in the homing process set a different current on the steppers so that the sensorless homing is
more flexible.
also spreadCycle can be used as option.

Related Issues

[FR] different driver current for sensorless_homing #15686

[thisiskeithb]

Have you tried homing faster? Sensorless homing with StallGuard tends to work better if things are moving quickly.

[danym21]

shure I have tried this, it crash on the machine much harder but will also not help when the head is very near the zero point, then there is not enough time to accelerate.

[thinkyhead]

I'm working on cleaning up and standardizing all the endstops code, including sensorless with DIAG0 and SPI-based sensorless. I notice that homing current was added to configurations for Z2, etc., but it is not implemented in the code. And later Z homing current was changed to only apply to DELTA. So, these are some issues I hope to work out in PR #25758 before it gets merged. Please add your commentary to that PR if you are still interested in this topic.