[PATCH v2] I2C: add driver for SMBus Control Method Interface

[Crane Cai <crane.cai-5C7GfCeVMHo@public.gmane.org>]

This driver supports the SMBus Control Method Interface. It needs BIOS declare
ACPI control methods which described in SMBus Control Method Interface Spec.
http://smbus.org/specs/smbus_cmi10.pdf

Hi Jean,
This driver is modified as you commented last time and it is verified OK. Could
you put some time to review and apply it?
Thanks.

Signed-off-by: Crane Cai <crane.cai-5C7GfCeVMHo@public.gmane.org>
---
 drivers/i2c/busses/Kconfig   |   11 +
 drivers/i2c/busses/Makefile  |    3 +
 drivers/i2c/busses/i2c-cmi.c |  442 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 456 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-cmi.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 8206442..afbc468 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -761,4 +761,15 @@ config SCx200_ACB
 	  This support is also available as a module.  If so, the module
 	  will be called scx200_acb.
 
+config I2C_CMI
+	tristate "SMBus Control Method Interface"
+	depends on ACPI
+	help
+	  This driver supports the SMBus Control Method Interface. It needs the
+	  BIOS to declare ACPI control methods as described in the SMBus Control
+	  Method Interface specification.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called i2c-cmi.
+
 endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index e654263..4e83162 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -2,6 +2,9 @@
 # Makefile for the i2c bus drivers.
 #
 
+# SMBus CMI driver
+obj-$(CONFIG_I2C_CMI)		+= i2c-cmi.o
+
 # PC SMBus host controller drivers
 obj-$(CONFIG_I2C_ALI1535)	+= i2c-ali1535.o
 obj-$(CONFIG_I2C_ALI1563)	+= i2c-ali1563.o
diff --git a/drivers/i2c/busses/i2c-cmi.c b/drivers/i2c/busses/i2c-cmi.c
new file mode 100644
index 0000000..555b482
--- /dev/null
+++ b/drivers/i2c/busses/i2c-cmi.c
@@ -0,0 +1,442 @@
+/*
+ * SMBus driver for ACPI SMBus CMI
+ *
+ * Copyright (C) 2009 Crane Cai <crane.cai-5C7GfCeVMHo@public.gmane.org>
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/stddef.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+
+#define ACPI_SMBUS_HC_COMPONENT		0x00080000
+#define ACPI_SMBUS_HC_CLASS		"smbus"
+#define ACPI_SMBUS_HC_DEVICE_NAME	"cmi"
+
+ACPI_MODULE_NAME("smbus_cmi");
+
+struct smbus_methods_t {
+	const char *mt_info;
+	const char *mt_sbr;
+	const char *mt_sbw;
+};
+
+struct acpi_smbus_cmi {
+	acpi_handle handle;
+	struct i2c_adapter adapter;
+	u8 cap_info:1;
+	u8 cap_read:1;
+	u8 cap_write:1;
+};
+
+static const struct smbus_methods_t smbus_methods = {
+	.mt_info = "_SBI",
+	.mt_sbr  = "_SBR",
+	.mt_sbw  = "_SBW",
+};
+
+static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
+	{"SMBUS01", 0},
+	{"", 0}
+};
+
+#define ACPI_SMBUS_STATUS_OK			0x00
+#define ACPI_SMBUS_STATUS_FAIL			0x07
+#define ACPI_SMBUS_STATUS_DNAK			0x10
+#define ACPI_SMBUS_STATUS_DERR			0x11
+#define ACPI_SMBUS_STATUS_CMD_DENY		0x12
+#define ACPI_SMBUS_STATUS_UNKNOWN		0x13
+#define ACPI_SMBUS_STATUS_ACC_DENY		0x17
+#define ACPI_SMBUS_STATUS_TIMEOUT		0x18
+#define ACPI_SMBUS_STATUS_NOTSUP		0x19
+#define ACPI_SMBUS_STATUS_BUSY			0x1A
+#define ACPI_SMBUS_STATUS_PEC			0x1F
+
+#define ACPI_SMBUS_PRTCL_WRITE			0x00
+#define ACPI_SMBUS_PRTCL_READ			0x01
+#define ACPI_SMBUS_PRTCL_QUICK			0x02
+#define ACPI_SMBUS_PRTCL_BYTE			0x04
+#define ACPI_SMBUS_PRTCL_BYTE_DATA		0x06
+#define ACPI_SMBUS_PRTCL_WORD_DATA		0x08
+#define ACPI_SMBUS_PRTCL_BLOCK_DATA		0x0a
+
+
+static int
+acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
+		   char read_write, u8 command, int size,
+		   union i2c_smbus_data *data)
+{
+	int result = 0;
+	struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
+	unsigned char protocol;
+	acpi_status status = 0;
+	struct acpi_object_list input;
+	union acpi_object mt_params[5];
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	union acpi_object *pkg;
+	char *method;
+	int len = 0;
+
+	dev_dbg(&adap->dev, "access size: %d %s\n", size,
+		(read_write) ? "READ" : "WRITE");
+	switch (size) {
+	case I2C_SMBUS_QUICK:
+		protocol = ACPI_SMBUS_PRTCL_QUICK;
+		command = 0;
+		if (read_write == I2C_SMBUS_WRITE) {
+			mt_params[3].type = ACPI_TYPE_INTEGER;
+			mt_params[3].integer.value = 0;
+			mt_params[4].type = ACPI_TYPE_INTEGER;
+			mt_params[4].integer.value = 0;
+		}
+		break;
+
+	case I2C_SMBUS_BYTE:
+		protocol = ACPI_SMBUS_PRTCL_BYTE;
+		if (read_write == I2C_SMBUS_WRITE) {
+			mt_params[3].type = ACPI_TYPE_INTEGER;
+			mt_params[3].integer.value = 0;
+			mt_params[4].type = ACPI_TYPE_INTEGER;
+			mt_params[4].integer.value = 0;
+		} else {
+			command = 0;
+		}
+		break;
+
+	case I2C_SMBUS_BYTE_DATA:
+		protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
+		if (read_write == I2C_SMBUS_WRITE) {
+			mt_params[3].type = ACPI_TYPE_INTEGER;
+			mt_params[3].integer.value = 1;
+			mt_params[4].type = ACPI_TYPE_INTEGER;
+			mt_params[4].integer.value = data->byte;
+		}
+		break;
+
+	case I2C_SMBUS_WORD_DATA:
+		protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
+		if (read_write == I2C_SMBUS_WRITE) {
+			mt_params[3].type = ACPI_TYPE_INTEGER;
+			mt_params[3].integer.value = 2;
+			mt_params[4].type = ACPI_TYPE_INTEGER;
+			mt_params[4].integer.value = data->word;
+		}
+		break;
+
+	case I2C_SMBUS_BLOCK_DATA:
+		protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
+		if (read_write == I2C_SMBUS_WRITE) {
+			len = data->block[0];
+			if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
+				return -EINVAL;
+			mt_params[3].type = ACPI_TYPE_INTEGER;
+			mt_params[3].integer.value = len;
+			mt_params[4].type = ACPI_TYPE_BUFFER;
+			mt_params[4].buffer.pointer = data->block + 1;
+		}
+		break;
+
+	default:
+		dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
+		return -EOPNOTSUPP;
+	}
+
+	if (read_write == I2C_SMBUS_READ) {
+		protocol |= ACPI_SMBUS_PRTCL_READ;
+		method = (char *)smbus_methods.mt_sbr;
+		input.count = 3;
+	} else {
+		protocol |= ACPI_SMBUS_PRTCL_WRITE;
+		method = (char *)smbus_methods.mt_sbw;
+		input.count = 5;
+	}
+
+	input.pointer = mt_params;
+	mt_params[0].type = ACPI_TYPE_INTEGER;
+	mt_params[0].integer.value = protocol;
+	mt_params[1].type = ACPI_TYPE_INTEGER;
+	mt_params[1].integer.value = addr;
+	mt_params[2].type = ACPI_TYPE_INTEGER;
+	mt_params[2].integer.value = command;
+
+	status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
+				      &buffer);
+	if (ACPI_FAILURE(status)) {
+		ACPI_ERROR((AE_INFO, "Evaluating %s: %i", method, status));
+		return -EIO;
+	}
+
+	pkg = buffer.pointer;
+	if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
+		obj = pkg->package.elements;
+	else {
+		ACPI_ERROR((AE_INFO, "Invalid argument type"));
+		result = -EIO;
+		goto out;
+	}
+	if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
+		ACPI_ERROR((AE_INFO, "Invalid argument type"));
+		result = -EIO;
+		goto out;
+	}
+
+	result = obj->integer.value;
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s return status: %i\n",
+			  method, result));
+
+	switch (result) {
+	case ACPI_SMBUS_STATUS_OK:
+		break;
+	case ACPI_SMBUS_STATUS_BUSY:
+		result = -EBUSY;
+		goto out;
+	case ACPI_SMBUS_STATUS_TIMEOUT:
+		result = -ETIMEDOUT;
+		goto out;
+	case ACPI_SMBUS_STATUS_DNAK:
+		result = -ENXIO;
+		goto out;
+	default:
+		result = -EIO;
+		goto out;
+	}
+
+	if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
+		goto out;
+
+	obj = pkg->package.elements + 1;
+	if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
+		ACPI_ERROR((AE_INFO, "Invalid argument type"));
+		result = -EIO;
+		goto out;
+	}
+
+	len = obj->integer.value;
+	obj = pkg->package.elements + 2;
+	switch (size) {
+	case I2C_SMBUS_BYTE:
+	case I2C_SMBUS_BYTE_DATA:
+	case I2C_SMBUS_WORD_DATA:
+		if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
+			ACPI_ERROR((AE_INFO, "Invalid argument type"));
+			result = -EIO;
+			goto out;
+		}
+		if (len == 2)
+			data->word = obj->integer.value;
+		else
+			data->byte = obj->integer.value;
+		break;
+	case I2C_SMBUS_BLOCK_DATA:
+		if (obj == NULL || obj->type != ACPI_TYPE_BUFFER) {
+			ACPI_ERROR((AE_INFO, "Invalid argument type"));
+			result = -EIO;
+			goto out;
+		}
+		if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
+			return -EPROTO;
+		data->block[0] = len;
+		memcpy(data->block + 1, obj->buffer.pointer, len);
+		break;
+	}
+
+out:
+	kfree(buffer.pointer);
+	dev_dbg(&adap->dev, "Transaction status: %i\n", result);
+	return result;
+}
+
+static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
+{
+	struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
+	u32 ret;
+
+	ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
+		I2C_FUNC_SMBUS_QUICK : 0;
+
+	ret |= smbus_cmi->cap_read ?
+		(I2C_FUNC_SMBUS_READ_BYTE |
+		I2C_FUNC_SMBUS_READ_BYTE_DATA |
+		I2C_FUNC_SMBUS_READ_WORD_DATA |
+		I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
+
+	ret |= smbus_cmi->cap_write ?
+		(I2C_FUNC_SMBUS_WRITE_BYTE |
+		I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+		I2C_FUNC_SMBUS_WRITE_WORD_DATA |
+		I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
+
+	return ret;
+}
+
+static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
+	.smbus_xfer = acpi_smbus_cmi_access,
+	.functionality = acpi_smbus_cmi_func,
+};
+
+static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
+				  const char *name)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	int i;
+	acpi_status status;
+
+	if (!strcmp(name, smbus_methods.mt_info)) {
+		status = acpi_evaluate_object(smbus_cmi->handle,
+					(char *)smbus_methods.mt_info,
+					NULL, &buffer);
+		if (ACPI_FAILURE(status)) {
+			ACPI_ERROR((AE_INFO, "Evaluating %s: %i",
+				   smbus_methods.mt_info, status));
+			return -EIO;
+		}
+
+		obj = buffer.pointer;
+		if (obj && obj->type == ACPI_TYPE_PACKAGE)
+			obj = obj->package.elements;
+		else {
+			ACPI_ERROR((AE_INFO, "Invalid argument type"));
+			kfree(buffer.pointer);
+			return -EIO;
+		}
+
+		if (obj->type != ACPI_TYPE_INTEGER) {
+			ACPI_ERROR((AE_INFO, "Invalid argument type"));
+			return -EIO;
+		} else
+			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "SMBus CMI Version %x"
+					  "\n", (int)obj->integer.value));
+
+		obj = obj->package.elements + 1;
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "SMB_INFO:\n"));
+		for (i = 0; i < obj->buffer.length; i++) {
+			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%02x ",
+						*(obj->buffer.pointer + i)));
+			if (i > 0 && (i % 16) == 0 && i != obj->buffer.length-1)
+				ACPI_DEBUG_PRINT((ACPI_DB_INFO, "\n"));
+		}
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "\n"));
+
+		kfree(buffer.pointer);
+		smbus_cmi->cap_info = 1;
+	} else if (!strcmp(name, smbus_methods.mt_sbr))
+		smbus_cmi->cap_read = 1;
+	else if (!strcmp(name, smbus_methods.mt_sbw))
+		smbus_cmi->cap_write = 1;
+	else
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "CMI Methods: %s\n", name));
+
+	return 0;
+}
+
+static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
+			void *context, void **return_value)
+{
+	char node_name[5];
+	struct acpi_buffer buffer = { sizeof(node_name), node_name };
+	struct acpi_smbus_cmi *smbus_cmi = context;
+	acpi_status status;
+
+	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
+
+	if (ACPI_SUCCESS(status))
+		acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
+
+	return AE_OK;
+}
+
+static int acpi_smbus_cmi_add(struct acpi_device *device)
+{
+	struct acpi_smbus_cmi *smbus_cmi;
+
+	smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
+	if (!smbus_cmi)
+		return -ENOMEM;
+
+	smbus_cmi->handle = device->handle;
+	strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
+	strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
+	device->driver_data = smbus_cmi;
+	smbus_cmi->cap_info = 0;
+	smbus_cmi->cap_read = 0;
+	smbus_cmi->cap_write = 0;
+
+	acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
+			    acpi_smbus_cmi_query_methods, smbus_cmi, NULL);
+
+	if (smbus_cmi->cap_info == 0)
+		goto err;
+
+	snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
+		"SMBus CMI adapter at %s-%s",
+		acpi_device_name(device),
+		acpi_device_uid(device));
+	smbus_cmi->adapter.owner = THIS_MODULE;
+	smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
+	smbus_cmi->adapter.algo_data = smbus_cmi;
+	smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	smbus_cmi->adapter.dev.parent = &device->dev;
+
+	if (i2c_add_adapter(&smbus_cmi->adapter)) {
+		dev_err(&device->dev, "Couldn't register adapter!\n");
+		goto err;
+	}
+
+	return 0;
+
+err:
+	kfree(smbus_cmi);
+	device->driver_data = NULL;
+	return -EIO;
+}
+
+static int acpi_smbus_cmi_remove(struct acpi_device *device, int type)
+{
+	struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
+
+	i2c_del_adapter(&smbus_cmi->adapter);
+	kfree(smbus_cmi);
+	smbus_cmi = NULL;
+
+	return 0;
+}
+
+static struct acpi_driver acpi_smbus_cmi_driver = {
+	.name = ACPI_SMBUS_HC_DEVICE_NAME,
+	.class = ACPI_SMBUS_HC_CLASS,
+	.ids = acpi_smbus_cmi_ids,
+	.ops = {
+		.add = acpi_smbus_cmi_add,
+		.remove = acpi_smbus_cmi_remove,
+	},
+};
+
+static int __init acpi_smbus_cmi_init(void)
+{
+	int result;
+
+	result = acpi_bus_register_driver(&acpi_smbus_cmi_driver);
+
+	return result;
+}
+
+static void __exit acpi_smbus_cmi_exit(void)
+{
+	acpi_bus_unregister_driver(&acpi_smbus_cmi_driver);
+}
+
+module_init(acpi_smbus_cmi_init);
+module_exit(acpi_smbus_cmi_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Crane Cai <crane.cai-5C7GfCeVMHo@public.gmane.org>");
+MODULE_DESCRIPTION("ACPI SMBus CMI driver");
-- 
1.6.0.4