skylake: Add I2C devices

Add the I2C devices to skylake with the scan_bus handler for SMBUS
devices so that I2C-based devices can be declared in devicetree.cb
and get initialized properly during ramstage.

This does not yet provide the I2C driver, but it allows for devices
that are declared in devicetree.cb to provide ACPI tables to the OS.

Change-Id: I9dfe4a06a8b0bc549a2b0e2d7c033c895188ba30
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/14992
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/skylake/Makefile.inc

@@ -39,6 +39,7 @@ ramstage-y += finalize.c
 ramstage-y += flash_controller.c
 ramstage-$(CONFIG_VBOOT_VERIFY_FIRMWARE) += fsp_reset.c
 ramstage-y += gpio.c
+ramstage-y += i2c.c
 ramstage-y += igd.c
 ramstage-y += lpc.c
 ramstage-y += me_status.c

src/soc/intel/skylake/i2c.c

@@ -0,0 +1,37 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <device/device.h>
+#include <device/pci.h>
+#include <device/pci_ids.h>
+#include <soc/ramstage.h>
+
+static struct device_operations i2c_dev_ops = {
+	.read_resources		= &pci_dev_read_resources,
+	.set_resources		= &pci_dev_set_resources,
+	.enable_resources	= &pci_dev_enable_resources,
+	.scan_bus		= &scan_smbus,
+	.ops_pci		= &soc_pci_ops,
+};
+
+static const unsigned short pci_device_ids[] = {
+	0x9d60, 0x9d61, 0x9d62, 0x9d63, 0x9d64, 0x9d65, 0
+};
+
+static const struct pci_driver pch_i2c __pci_driver = {
+	.ops	 = &i2c_dev_ops,
+	.vendor	 = PCI_VENDOR_ID_INTEL,
+	.devices = pci_device_ids,
+};