i2c: Add Intel SCH SMBus support

New i2c bus driver for the Intel SCH chipsets (AF82US15W, AF82US15L,
AF82UL11L).

Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

3 files changed, 347 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2b0874b0ad11..56b6f29c9a3c 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -101,6 +101,16 @@ config I2C_I801
           This driver can also be built as a module.  If so, the module
           will be called i2c-i801.
 
+config I2C_ISCH
+        tristate "Intel SCH SMBus 1.0"
+        depends on PCI
+        help
+          Say Y here if you want to use SMBus controller on the Intel SCH
+          based systems.
+
+          This driver can also be built as a module. If so, the module
+          will be called i2c-isch.
+
 config I2C_PIIX4
         tristate "Intel PIIX4 and compatible (ATI/Serverworks/Broadcom/SMSC)"
         depends on PCI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 48a6a5bddc5e..cbeac7dc9bfc 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_I2C_AMD756)	+= i2c-amd756.o
 obj-$(CONFIG_I2C_AMD756_S4882)  += i2c-amd756-s4882.o
 obj-$(CONFIG_I2C_AMD8111)       += i2c-amd8111.o
 obj-$(CONFIG_I2C_I801)          += i2c-i801.o
+obj-$(CONFIG_I2C_ISCH)          += i2c-isch.o
 obj-$(CONFIG_I2C_NFORCE2)       += i2c-nforce2.o
 obj-$(CONFIG_I2C_NFORCE2_S4985) += i2c-nforce2-s4985.o
 obj-$(CONFIG_I2C_PIIX4)         += i2c-piix4.o
diff --git a/drivers/i2c/busses/i2c-isch.c b/drivers/i2c/busses/i2c-isch.c
new file mode 100644
index 000000000000..c9cd46b22692
--- /dev/null
+++ b/drivers/i2c/busses/i2c-isch.c
@@ -0,0 +1,336 @@
+/*
+    i2c-isch.c - Linux kernel driver for Intel SCH chipset SMBus
+    - Based on i2c-piix4.c
+    Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and
+    Philip Edelbrock <phil@netroedge.com>
+    - Intel SCH support
+    Copyright (c) 2007 - 2008 Jacob Jun Pan <jacob.jun.pan@intel.com>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License version 2 as
+    published by the Free Software Foundation.
+
+    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.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/*
+   Supports:
+        Intel SCH chipsets (AF82US15W, AF82US15L, AF82UL11L)
+   Note: we assume there can only be one device, with one SMBus interface.
+*/
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/stddef.h>
+#include <linux/ioport.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/io.h>
+
+/* SCH SMBus address offsets */
+#define SMBHSTCNT       (0 + sch_smba)
+#define SMBHSTSTS       (1 + sch_smba)
+#define SMBHSTADD       (4 + sch_smba) /* TSA */
+#define SMBHSTCMD       (5 + sch_smba)
+#define SMBHSTDAT0      (6 + sch_smba)
+#define SMBHSTDAT1      (7 + sch_smba)
+#define SMBBLKDAT       (0x20 + sch_smba)
+
+/* count for request_region */
+#define SMBIOSIZE       64
+
+/* PCI Address Constants */
+#define SMBBA_SCH       0x40
+
+/* Other settings */
+#define MAX_TIMEOUT     500
+
+/* I2C constants */
+#define SCH_QUICK               0x00
+#define SCH_BYTE                0x01
+#define SCH_BYTE_DATA           0x02
+#define SCH_WORD_DATA           0x03
+#define SCH_BLOCK_DATA          0x05
+
+static unsigned short sch_smba;
+static struct pci_driver sch_driver;
+static struct i2c_adapter sch_adapter;
+
+/*
+ * Start the i2c transaction -- the i2c_access will prepare the transaction
+ * and this function will execute it.
+ * return 0 for success and others for failure.
+ */
+static int sch_transaction(void)
+{
+        int temp;
+        int result = 0;
+        int timeout = 0;
+
+        dev_dbg(&sch_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, "
+                "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
+                inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
+                inb(SMBHSTDAT1));
+
+        /* Make sure the SMBus host is ready to start transmitting */
+        temp = inb(SMBHSTSTS) & 0x0f;
+        if (temp) {
+                /* Can not be busy since we checked it in sch_access */
+                if (temp & 0x01) {
+                        dev_dbg(&sch_adapter.dev, "Completion (%02x). "
+                                "Clear...\n", temp);
+                }
+                if (temp & 0x06) {
+                        dev_dbg(&sch_adapter.dev, "SMBus error (%02x). "
+                                "Resetting...\n", temp);
+                }
+                outb(temp, SMBHSTSTS);
+                temp = inb(SMBHSTSTS) & 0x0f;
+                if (temp) {
+                        dev_err(&sch_adapter.dev,
+                                "SMBus is not ready: (%02x)\n", temp);
+                        return -EAGAIN;
+                }
+        }
+
+        /* start the transaction by setting bit 4 */
+        outb(inb(SMBHSTCNT) | 0x10, SMBHSTCNT);
+
+        do {
+                msleep(1);
+                temp = inb(SMBHSTSTS) & 0x0f;
+        } while ((temp & 0x08) && (timeout++ < MAX_TIMEOUT));
+
+        /* If the SMBus is still busy, we give up */
+        if (timeout >= MAX_TIMEOUT) {
+                dev_err(&sch_adapter.dev, "SMBus Timeout!\n");
+                result = -ETIMEDOUT;
+        }
+        if (temp & 0x04) {
+                result = -EIO;
+                dev_dbg(&sch_adapter.dev, "Bus collision! SMBus may be "
+                        "locked until next hard reset. (sorry!)\n");
+                /* Clock stops and slave is stuck in mid-transmission */
+        } else if (temp & 0x02) {
+                result = -EIO;
+                dev_err(&sch_adapter.dev, "Error: no response!\n");
+        } else if (temp & 0x01) {
+                dev_dbg(&sch_adapter.dev, "Post complete!\n");
+                outb(temp, SMBHSTSTS);
+                temp = inb(SMBHSTSTS) & 0x07;
+                if (temp & 0x06) {
+                        /* Completion clear failed */
+                        dev_dbg(&sch_adapter.dev, "Failed reset at end of "
+                                "transaction (%02x), Bus error!\n", temp);
+                }
+        } else {
+                result = -ENXIO;
+                dev_dbg(&sch_adapter.dev, "No such address.\n");
+        }
+        dev_dbg(&sch_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, "
+                "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
+                inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
+                inb(SMBHSTDAT1));
+        return result;
+}
+
+/*
+ * This is the main access entry for i2c-sch access
+ * adap is i2c_adapter pointer, addr is the i2c device bus address, read_write
+ * (0 for read and 1 for write), size is i2c transaction type and data is the
+ * union of transaction for data to be transfered or data read from bus.
+ * return 0 for success and others for failure.
+ */
+static s32 sch_access(struct i2c_adapter *adap, u16 addr,
+                 unsigned short flags, char read_write,
+                 u8 command, int size, union i2c_smbus_data *data)
+{
+        int i, len, temp, rc;
+
+        /* Make sure the SMBus host is not busy */
+        temp = inb(SMBHSTSTS) & 0x0f;
+        if (temp & 0x08) {
+                dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp);
+                return -EAGAIN;
+        }
+        dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size,
+                (read_write)?"READ":"WRITE");
+        switch (size) {
+        case I2C_SMBUS_QUICK:
+                outb((addr << 1) | read_write, SMBHSTADD);
+                size = SCH_QUICK;
+                break;
+        case I2C_SMBUS_BYTE:
+                outb((addr << 1) | read_write, SMBHSTADD);
+                if (read_write == I2C_SMBUS_WRITE)
+                        outb(command, SMBHSTCMD);
+                size = SCH_BYTE;
+                break;
+        case I2C_SMBUS_BYTE_DATA:
+                outb((addr << 1) | read_write, SMBHSTADD);
+                outb(command, SMBHSTCMD);
+                if (read_write == I2C_SMBUS_WRITE)
+                        outb(data->byte, SMBHSTDAT0);
+                size = SCH_BYTE_DATA;
+                break;
+        case I2C_SMBUS_WORD_DATA:
+                outb((addr << 1) | read_write, SMBHSTADD);
+                outb(command, SMBHSTCMD);
+                if (read_write == I2C_SMBUS_WRITE) {
+                        outb(data->word & 0xff, SMBHSTDAT0);
+                        outb((data->word & 0xff00) >> 8, SMBHSTDAT1);
+                }
+                size = SCH_WORD_DATA;
+                break;
+        case I2C_SMBUS_BLOCK_DATA:
+                outb((addr << 1) | read_write, SMBHSTADD);
+                outb(command, SMBHSTCMD);
+                if (read_write == I2C_SMBUS_WRITE) {
+                        len = data->block[0];
+                        if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
+                                return -EINVAL;
+                        outb(len, SMBHSTDAT0);
+                        for (i = 1; i <= len; i++)
+                                outb(data->block[i], SMBBLKDAT+i-1);
+                }
+                size = SCH_BLOCK_DATA;
+                break;
+        default:
+                dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
+                return -EOPNOTSUPP;
+        }
+        dev_dbg(&sch_adapter.dev, "write size %d to 0x%04x\n", size, SMBHSTCNT);
+        outb((inb(SMBHSTCNT) & 0xb0) | (size & 0x7), SMBHSTCNT);
+
+        rc = sch_transaction();
+        if (rc) /* Error in transaction */
+                return rc;
+
+        if ((read_write == I2C_SMBUS_WRITE) || (size == SCH_QUICK))
+                return 0;
+
+        switch (size) {
+        case SCH_BYTE:
+        case SCH_BYTE_DATA:
+                data->byte = inb(SMBHSTDAT0);
+                break;
+        case SCH_WORD_DATA:
+                data->word = inb(SMBHSTDAT0) + (inb(SMBHSTDAT1) << 8);
+                break;
+        case SCH_BLOCK_DATA:
+                data->block[0] = inb(SMBHSTDAT0);
+                if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
+                        return -EPROTO;
+                for (i = 1; i <= data->block[0]; i++)
+                        data->block[i] = inb(SMBBLKDAT+i-1);
+                break;
+        }
+        return 0;
+}
+
+static u32 sch_func(struct i2c_adapter *adapter)
+{
+        return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+            I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+            I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm smbus_algorithm = {
+        .smbus_xfer     = sch_access,
+        .functionality  = sch_func,
+};
+
+static struct i2c_adapter sch_adapter = {
+        .owner          = THIS_MODULE,
+        .class          = I2C_CLASS_HWMON,
+        .algo           = &smbus_algorithm,
+};
+
+static struct pci_device_id sch_ids[] = {
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_SCH_LPC) },
+        { 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, sch_ids);
+
+static int __devinit sch_probe(struct pci_dev *dev,
+                                const struct pci_device_id *id)
+{
+        int retval;
+        unsigned int smba;
+
+        pci_read_config_dword(dev, SMBBA_SCH, &smba);
+        if (!(smba & (1 << 31))) {
+                dev_err(&dev->dev, "SMBus I/O space disabled!\n");
+                return -ENODEV;
+        }
+
+        sch_smba = (unsigned short)smba;
+        if (sch_smba == 0) {
+                dev_err(&dev->dev, "SMBus base address uninitialized!\n");
+                return -ENODEV;
+        }
+        if (!request_region(sch_smba, SMBIOSIZE, sch_driver.name)) {
+                dev_err(&dev->dev, "SMBus region 0x%x already in use!\n",
+                        sch_smba);
+                return -EBUSY;
+        }
+        dev_dbg(&dev->dev, "SMBA = 0x%X\n", sch_smba);
+
+        /* set up the sysfs linkage to our parent device */
+        sch_adapter.dev.parent = &dev->dev;
+
+        snprintf(sch_adapter.name, sizeof(sch_adapter.name),
+                "SMBus SCH adapter at %04x", sch_smba);
+
+        retval = i2c_add_adapter(&sch_adapter);
+        if (retval) {
+                dev_err(&dev->dev, "Couldn't register adapter!\n");
+                release_region(sch_smba, SMBIOSIZE);
+                sch_smba = 0;
+        }
+
+        return retval;
+}
+
+static void __devexit sch_remove(struct pci_dev *dev)
+{
+        if (sch_smba) {
+                i2c_del_adapter(&sch_adapter);
+                release_region(sch_smba, SMBIOSIZE);
+                sch_smba = 0;
+        }
+}
+
+static struct pci_driver sch_driver = {
+        .name           = "isch_smbus",
+        .id_table       = sch_ids,
+        .probe          = sch_probe,
+        .remove         = __devexit_p(sch_remove),
+};
+
+static int __init i2c_sch_init(void)
+{
+        return pci_register_driver(&sch_driver);
+}
+
+static void __exit i2c_sch_exit(void)
+{
+        pci_unregister_driver(&sch_driver);
+}
+
+MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>");
+MODULE_DESCRIPTION("Intel SCH SMBus driver");
+MODULE_LICENSE("GPL");
+
+module_init(i2c_sch_init);
+module_exit(i2c_sch_exit);