ig4: Add PCI IDs for Intel Tiger Lake

[nc]

Summary

ig4: Add PCI IDs for Intel Tiger Lake

Submitted by: Neel Chauhan <neel AT neelc DOT org>

Test Plan

Test say iichid on a system with Intel Tiger Lake and this patch.

[nc]

Keep in mind that I do not have a Tiger Lake system. I am considering getting one but am not sure yet: I want to see if my current 2018 HP Spectre x360 13 works fine now that I disabled WITNESS, or if I need a new laptop (this time with no battery guzzling 4K) which probably will have Tiger Lake (because there's no ultrabook with AMD Ryzen).

This patch is based on the Linux source, Links:

https://github.com/torvalds/linux/blob/e6037a753e8e9a4146f7d94c32eb30a6717c9c70/drivers/mfd/intel-lpss-pci.c#L325 (Tiger Lake LP)
https://github.com/torvalds/linux/blob/e6037a753e8e9a4146f7d94c32eb30a6717c9c70/drivers/mfd/intel-lpss-pci.c#L236 (Tiger Lake H)
https://github.com/torvalds/linux/blob/master/drivers/mfd/intel-lpss-pci.c#L120 (Clock for Tiger Lake H)

Keep in mind that Tiger Lake-LP uses the same IIC clock as Skylake.

Sorry, I am not an expert on PC hardware. Yes, I do work at Microsoft, but not on Windows or anything close to hardware (If I was on Windows, I'd probably not be posting FreeBSD patches or even using BSD as a personal desktop).

[wulf]

sys/dev/ichiic/ig4_iic.c

124 ↗

(On Diff #80351)

Intel uses some custom values for timings here: https://github.com/torvalds/linux/blob/master/drivers/mfd/intel-lpss-pci.c#L101
For some reasons they set SDA HOLD time very low (42ns instead of 300ns), but I think they know what they do.

[nc]

Thanks for committing! I did order an Tiger Lake HP Spectre x360 (well, after cancelling an Cannon Lake EliteBook).

Also, could you @wulf (or someone else) please MFC this patch?

[wulf]

In D27483#614381, @neel_neelc.org wrote:

Also, could you @wulf (or someone else) please MFC this patch?

I am going to MFC it in week or two.