Attention is currently required from: Paul Menzel. Werner Zeh has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/55089 )
Change subject: mb/siemens/mc_apl{1,2,3,5,6}: Provide I2C timings for 400 kHz ......................................................................
Patch Set 2:
(3 comments)
Commit Message:
https://review.coreboot.org/c/coreboot/+/55089/comment/12e49ce3_aced6549 PS2, Line 11: set up
Noun: setup
Yes, will change.
https://review.coreboot.org/c/coreboot/+/55089/comment/7684870f_80ab657c PS2, Line 13: Report additional bus timings for fast mode so that OS can do it right.
Could you please document, where you got the values from?
I am not sure if it makes sense to mention it in the commit message but what I did is: Chose a set of values after a manual computation and verify by a measurement on the I2C-Bus (oscilloscope). Then tune the values until the timing is valid.
File src/mainboard/siemens/mc_apl1/variants/mc_apl1/devicetree.cb:
https://review.coreboot.org/c/coreboot/+/55089/comment/b9e13d5a_1ef3411b PS2, Line 55: .scl_hcnt = 0x58,
Would using decimal base be more useful?
Since these values represent ticks in multiple of host clock (133 MHz for APL) I do not see any benefit in a decimal notation here.