3 files changed, 25 insertions, 6 deletions

diff --git a/Documentation/i2c/busses/i2c-piix4 b/Documentation/i2c/busses/i2c-piix4
index c097e0f020fe..aa959fd22450 100644
--- a/Documentation/i2c/busses/i2c-piix4
+++ b/Documentation/i2c/busses/i2c-piix4
@@ -13,7 +13,7 @@ Supported adapters:
   * AMD SP5100 (SB700 derivative found on some server mainboards)
     Datasheet: Publicly available at the AMD website
     http://support.amd.com/us/Embedded_TechDocs/44413.pdf
-  * AMD Hudson-2, CZ
+  * AMD Hudson-2, ML, CZ
     Datasheet: Not publicly available
   * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge
     Datasheet: Publicly available at the SMSC website http://www.smsc.com
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 6bcdea5856af..f5ed03164d86 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -152,6 +152,7 @@ config I2C_PIIX4
             ATI SB700/SP5100
             ATI SB800
             AMD Hudson-2
+            AMD ML
             AMD CZ
             Serverworks OSB4
             Serverworks CSB5
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index a028617b8f13..f71b4d381c00 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -22,7 +22,7 @@
         Intel PIIX4, 440MX
         Serverworks OSB4, CSB5, CSB6, HT-1000, HT-1100
         ATI IXP200, IXP300, IXP400, SB600, SB700/SP5100, SB800
-        AMD Hudson-2, CZ
+        AMD Hudson-2, ML, CZ
         SMSC Victory66
 
    Note: we assume there can only be one device, with one or more
@@ -235,7 +235,8 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
 {
         unsigned short piix4_smba;
         unsigned short smba_idx = 0xcd6;
-        u8 smba_en_lo, smba_en_hi, i2ccfg, i2ccfg_offset = 0x10, smb_en;
+        u8 smba_en_lo, smba_en_hi, smb_en, smb_en_status;
+        u8 i2ccfg, i2ccfg_offset = 0x10;
 
         /* SB800 and later SMBus does not support forcing address */
         if (force || force_addr) {
@@ -245,7 +246,15 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
         }
 
         /* Determine the address of the SMBus areas */
-        smb_en = (aux) ? 0x28 : 0x2c;
+        if ((PIIX4_dev->vendor == PCI_VENDOR_ID_AMD &&
+             PIIX4_dev->device == PCI_DEVICE_ID_AMD_HUDSON2_SMBUS &&
+             PIIX4_dev->revision >= 0x41) ||
+            (PIIX4_dev->vendor == PCI_VENDOR_ID_AMD &&
+             PIIX4_dev->device == 0x790b &&
+             PIIX4_dev->revision >= 0x49))
+                smb_en = 0x00;
+        else
+                smb_en = (aux) ? 0x28 : 0x2c;
 
         if (!request_region(smba_idx, 2, "smba_idx")) {
                 dev_err(&PIIX4_dev->dev, "SMBus base address index region "
@@ -258,13 +267,22 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
         smba_en_hi = inb_p(smba_idx + 1);
         release_region(smba_idx, 2);
 
-        if ((smba_en_lo & 1) == 0) {
+        if (!smb_en) {
+                smb_en_status = smba_en_lo & 0x10;
+                piix4_smba = smba_en_hi << 8;
+                if (aux)
+                        piix4_smba |= 0x20;
+        } else {
+                smb_en_status = smba_en_lo & 0x01;
+                piix4_smba = ((smba_en_hi << 8) | smba_en_lo) & 0xffe0;
+        }
+
+        if (!smb_en_status) {
                 dev_err(&PIIX4_dev->dev,
                         "Host SMBus controller not enabled!\n");
                 return -ENODEV;
         }
 
-        piix4_smba = ((smba_en_hi << 8) | smba_en_lo) & 0xffe0;
         if (acpi_check_region(piix4_smba, SMBIOSIZE, piix4_driver.name))
                 return -ENODEV;