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/bus lines. The multiplexer adapter device defines the address
to select the adapter/client lines. These ACPI identifiers are consumed
by the i2c-mux-gpio kernel driver:
https://www.kernel.org/doc/html/latest/i2c/muxes/i2c-mux-gpio.html

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)
    {
        Name (_HID, "PRP0001")  // _HID: Hardware ID
        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 (0x02)
            {
                Package (0x02)
                {
                    "compatible",
                    "i2c-mux-gpio"
                },

                Package (0x02)
                {
                    "mux-gpios",
                    Package (0x04)
                    {
                        \_SB.PCI0.I2C3.MUX0,
                        Zero,
                        Zero,
                        Zero
                    }
                }
            }
        })
    }
}

Change-Id: Ib371108cc6043c133681066bf7bf4b2e00771e8b
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45911
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/drivers/i2c/gpiomux/mux/Makefile.inc b/src/drivers/i2c/gpiomux/mux/Makefile.inc
new file mode 100644
index 0000000000..e51f706eda
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/mux/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_I2C_GPIO_MUX) += mux.c