[L] Change in coreboot[master]: drivers/i2c: Add PI7C9X2G608GP PCIe switch driver (pi608gp)

[Jan Samek (Code Review)]

Attention is currently required from: Mario Scheithauer, Lean Sheng Tan, Werner Zeh, Jan Samek.

Hello build bot (Jenkins), Mario Scheithauer, Arthur Heymans, Lean Sheng Tan, Werner Zeh,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/74433

to look at the new patch set (#13).

Change subject: drivers/i2c: Add PI7C9X2G608GP PCIe switch driver (pi608gp)
......................................................................

drivers/i2c: Add PI7C9X2G608GP PCIe switch driver (pi608gp)

This patch adds some of the variety of configuration options exported
by the Pericom Inc. PI7C9X2G608GP PCIe switch over its SMBus interface.

Currently implemented options are only used to adjust the switch
upstream port amplitude and de-emphasis levels in millivolts. Only
values specified in the switch datasheet (in tables 6-6 and 6-8) are
allowed.

Example of a devicetree.cb entry:

chip drivers/i2c/pi608gp
    	register "gen2_3p5_enable" = "true"
    	register "gen2_3p5_amp" = "AMP_LVL_MV(425)"
    	register "gen2_3p5_deemph" = \
    			"DEEMPH_LVL_MV(37, 5)"
    	device i2c 0x6f on
    		ops pi608gp_ops
    	end
    end

Link to the datasheet:
https://web.archive.org/web/20210225074853/https://www.diodes.com/assets/Dat...

BUG=none
TEST=Create devicetree.cb and Kconfig entries for this driver
in a mainboard containing the switch and verify, that the values read
out from the switch config space match the values programmed over the
SMBus.

Change-Id: Id191c4e97b99da58efd3ba38bf8cca3603ece4d5
Signed-off-by: Jan Samek 
---
A src/drivers/i2c/pi608gp/Kconfig
A src/drivers/i2c/pi608gp/Makefile.inc
A src/drivers/i2c/pi608gp/chip.h
A src/drivers/i2c/pi608gp/pi608gp.c
A src/drivers/i2c/pi608gp/pi608gp.h
5 files changed, 255 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/33/74433/13