Change in coreboot[master]: drivers/i2c: Add chip driver for GPIO based I2C multiplexer

[Karthik Ramasubramanian (Code Review)]

Hello Patrick Georgi, Martin Roth, Furquan Shaikh, Justin TerAvest, Evan Green, Duncan Laurie, Tim Wawrzynczak,

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

https://review.coreboot.org/c/coreboot/+/45911

to look at the new patch set (#5).

Change subject: drivers/i2c: Add chip driver for GPIO based I2C multiplexer
......................................................................

drivers/i2c: Add chip driver for GPIO based I2C multiplexer

Add identifiers in ACPI tables for GPIO based I2C multiplexer. The
multiplexer device defines the GPIO resource used to select the
adapter/client lines. The multiplexer adapter device defines the address
to select the adapter/client lines.

BUG=b:169444894
TEST=Build and boot waddledee to OS. Ensure that the ACPI identifiers
are added for I2C devices multiplexed using I2C MUX under the
appropriate scope. Here is the output SSDT:
Scope (_SB.PCI0.I2C3)
{
    Device (MUX0)
    {
        Method (_STA, 0, NotSerialized)  // _STA: Status
        {
            Return (0x0F)
        }

Name (_CRS, ResourceTemplate ()  // _CRS: Current Resource Settings
        {
            GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly,
                 "\_SB.PCI0.GPIO", 0x00, ResourceConsumer, ,
                 )
            {   // Pin list
                0x0125
            }
        })
        Name (_DSD, Package (0x02)  // _DSD: Device-Specific Data
        {
            ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device Properties for _DSD */,
            Package (0x01)
            {
                Package (0x02)
                {
                    "mux-gpios",
                    Package (0x04)
                    {
                        _SB.PCI0.I2C3.MUX0,
                        Zero,
                        Zero,
                        Zero
                    }
                }
            }
        })
    }
}

Scope (_SB.PCI0.I2C3.MUX0)
{
    Device (MXA0)
    {
        Method (_STA, 0, NotSerialized)  // _STA: Status
        {
            Return (0x0F)
        }

Name (_ADR, Zero)  // _ADR: Address
    }
}

Scope (_SB.PCI0.I2C3.MUX0)
{
    Device (MXA1)
    {
        Method (_STA, 0, NotSerialized)  // _STA: Status
        {
            Return (0x0F)
        }

Name (_ADR, One)  // _ADR: Address
    }
}

Change-Id: Ib371108cc6043c133681066bf7bf4b2e00771e8b
Signed-off-by: Karthikeyan Ramasubramanian 
---
A src/drivers/i2c/gpio_mux/Kconfig
A src/drivers/i2c/gpio_mux/Makefile.inc
A src/drivers/i2c/gpio_mux/chip.h
A src/drivers/i2c/gpio_mux/gpio_mux.c
4 files changed, 146 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/11/45911/5