drivers/i2c/generic: Re-factor SSDT generation code

1. Export i2c_generic_fill_ssdt to allow other device-specific i2c
drivers to share and re-use the same code for generating AML code for
SSDT. In order to achieve this, following changes are required:
 a. Add macro I2C_GENERIC_CONFIG that defines a structure with all
 generic i2c device-tree properties. This macro should be placed by the
 using driver at the start of its config structure.
 b. Accept a callback function to add any device specific information to
 SSDT. If generic driver is used directly by a device, callback would be
 NULL. Other devices using a separate i2c driver can provide a callback
 to add any properties to SSDT.
2. Allow device to provide _CID.

BUG=chrome-os-partner:57846

Change-Id: I3a0054e22b81f9d6d407bef417eae5e9edc04ee4
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/17089
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/drivers/i2c/generic/chip.h

@@ -1,8 +1,27 @@
+/*
+ * 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.
+ */
+
+#ifndef __I2C_GENERIC_CHIP_H__
+#define __I2C_GENERIC_CHIP_H__
+
 #include <arch/acpi_device.h>
 #include <device/i2c.h>
 
 struct drivers_i2c_generic_config {
 	const char *hid;	/* ACPI _HID (required) */
+	const char *cid;	/* ACPI _CID */
 	const char *name;	/* ACPI Device Name */
 	const char *desc;	/* Device Description */
 	unsigned uid;		/* ACPI _UID */
@@ -32,3 +51,17 @@ struct drivers_i2c_generic_config {
 	/* Delay to be inserted after device is enabled. */
 	unsigned enable_delay_ms;
 };
+
+/*
+ * Fills in generic information about i2c device from device-tree
+ * properties. Callback can be provided to fill in any
+ * device-specific information in SSDT.
+ *
+ * Drivers calling into this function to generate should place
+ * drivers_i2c_generic_config structure at the beginning of their device config
+ * structure.
+ */
+void i2c_generic_fill_ssdt(struct device *dev,
+			   void (*callback)(struct device *dev));
+
+#endif /* __I2C_GENERIC_CHIP_H__ */

src/drivers/i2c/generic/generic.c

@@ -65,7 +65,8 @@ static void i2c_generic_add_power_res(struct drivers_i2c_generic_config *config)
 	acpigen_pop_len();		/* PowerResource PRIC */
 }
 
-static void i2c_generic_fill_ssdt(struct device *dev)
+void i2c_generic_fill_ssdt(struct device *dev,
+			   void (*callback)(struct device *dev))
 {
 	struct drivers_i2c_generic_config *config = dev->chip_info;
 	const char *scope = acpi_device_scope(dev);
@@ -89,6 +90,8 @@ static void i2c_generic_fill_ssdt(struct device *dev)
 	acpigen_write_scope(scope);
 	acpigen_write_device(acpi_device_name(dev));
 	acpigen_write_name_string("_HID", config->hid);
+	if (config->cid)
+		acpigen_write_name_string("_CID", config->cid);
 	acpigen_write_name_integer("_UID", config->uid);
 	acpigen_write_name_string("_DDN", config->desc);
 	acpigen_write_STA(ACPI_STATUS_DEVICE_ALL_ON);
@@ -115,6 +118,10 @@ static void i2c_generic_fill_ssdt(struct device *dev)
 	/* Power Resource */
 	i2c_generic_add_power_res(config);
 
+	/* Callback if any. */
+	if (callback)
+		callback(dev);
+
 	acpigen_pop_len(); /* Device */
 	acpigen_pop_len(); /* Scope */
 
@@ -122,6 +129,11 @@ static void i2c_generic_fill_ssdt(struct device *dev)
 	       config->desc ? : dev->chip_ops->name, dev_path(dev));
 }
 
+static void i2c_generic_fill_ssdt_generator(struct device *dev)
+{
+	i2c_generic_fill_ssdt(dev, NULL);
+}
+
 /* Use name specified in config or build one from I2C address */
 static const char *i2c_generic_acpi_name(struct device *dev)
 {
@@ -143,7 +155,7 @@ static struct device_operations i2c_generic_ops = {
 	.enable_resources	  = DEVICE_NOOP,
 #if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
 	.acpi_name		  = &i2c_generic_acpi_name,
-	.acpi_fill_ssdt_generator = &i2c_generic_fill_ssdt,
+	.acpi_fill_ssdt_generator = &i2c_generic_fill_ssdt_generator,
 #endif
 };