i2c: Add driver for SMBus Control Method Interface
authorCrane Cai <crane.cai@amd.com>
Fri, 18 Sep 2009 20:45:51 +0000 (22:45 +0200)
committerJean Delvare <khali@linux-fr.org>
Fri, 18 Sep 2009 20:45:51 +0000 (22:45 +0200)
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

Signed-off-by: Crane Cai <crane.cai@amd.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
drivers/i2c/busses/Kconfig
drivers/i2c/busses/Makefile
drivers/i2c/busses/i2c-scmi.c [new file with mode: 0644]

index bb216c5..838bd1e 100644 (file)
@@ -762,4 +762,15 @@ config SCx200_ACB
          This support is also available as a module.  If so, the module
          will be called scx200_acb.
 
+config I2C_SCMI
+       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-scmi.
+
 endmenu
index e654263..060da43 100644 (file)
@@ -2,6 +2,9 @@
 # Makefile for the i2c bus drivers.
 #
 
+# SMBus CMI driver
+obj-$(CONFIG_I2C_SCMI)         += i2c-scmi.o
+
 # PC SMBus host controller drivers
 obj-$(CONFIG_I2C_ALI1535)      += i2c-ali1535.o
 obj-$(CONFIG_I2C_ALI1563)      += i2c-ali1563.o
diff --git a/drivers/i2c/busses/i2c-scmi.c b/drivers/i2c/busses/i2c-scmi.c
new file mode 100644 (file)
index 0000000..276a046
--- /dev/null
@@ -0,0 +1,430 @@
+/*
+ * SMBus driver for ACPI SMBus CMI
+ *
+ * Copyright (C) 2009 Crane Cai <crane.cai@amd.com>
+ *
+ * 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_CLASS            "smbus"
+#define ACPI_SMBUS_HC_DEVICE_NAME      "cmi"
+
+ACPI_MODULE_NAME("smbus_cmi");
+
+struct smbus_methods_t {
+       char *mt_info;
+       char *mt_sbr;
+       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 = smbus_methods.mt_sbr;
+               input.count = 3;
+       } else {
+               protocol |= ACPI_SMBUS_PRTCL_WRITE;
+               method = 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:
+               result = 0;
+               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;
+       acpi_status status;
+
+       if (!strcmp(name, smbus_methods.mt_info)) {
+               status = acpi_evaluate_object(smbus_cmi->handle,
+                                       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"));
+                       kfree(buffer.pointer);
+                       return -EIO;
+               } else
+                       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "SMBus CMI Version %x"
+                                         "\n", (int)obj->integer.value));
+
+               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, "Unsupported CMI method: %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 %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);
+       device->driver_data = 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)
+{
+       return acpi_bus_register_driver(&acpi_smbus_cmi_driver);
+}
+
+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@amd.com>");
+MODULE_DESCRIPTION("ACPI SMBus CMI driver");