i2c-piix4: Support AMD auxiliary SMBus controller

Some AMD chipsets, such as the SP5100, have an auxiliary SMBus
controller with a second set of registers. This patch adds
support for this auxiliary controller.

Tested on ASUS KCMA-D8 motherboard.

Signed-off-by: Andrew Armenia <andrew@asquaredlabs.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 68 insertions, 3 deletions

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 42ed0af10efd..ef511df2c965 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -21,11 +21,12 @@
    Supports:
         Intel PIIX4, 440MX
         Serverworks OSB4, CSB5, CSB6, HT-1000, HT-1100
-        ATI IXP200, IXP300, IXP400, SB600, SB700, SB800
+        ATI IXP200, IXP300, IXP400, SB600, SB700/SP5100, SB800
         AMD Hudson-2
         SMSC Victory66
 
-   Note: we assume there can only be one device, with one SMBus interface.
+   Note: we assume there can only be one device, with one or more
+   SMBus interfaces.
 */
 
 #include <linux/module.h>
@@ -293,6 +294,46 @@ static int __devinit piix4_setup_sb800(struct pci_dev *PIIX4_dev,
         return piix4_smba;
 }
 
+static int __devinit piix4_setup_aux(struct pci_dev *PIIX4_dev,
+                                const struct pci_device_id *id,
+                                unsigned short base_reg_addr)
+{
+        /* Set up auxiliary SMBus controllers found on some
+         * AMD chipsets e.g. SP5100 (SB700 derivative) */
+
+        unsigned short piix4_smba;
+
+        /* Read address of auxiliary SMBus controller */
+        pci_read_config_word(PIIX4_dev, base_reg_addr, &piix4_smba);
+        if ((piix4_smba & 1) == 0) {
+                dev_dbg(&PIIX4_dev->dev,
+                        "Auxiliary SMBus controller not enabled\n");
+                return -ENODEV;
+        }
+
+        piix4_smba &= 0xfff0;
+        if (piix4_smba == 0) {
+                dev_dbg(&PIIX4_dev->dev,
+                        "Auxiliary SMBus base address uninitialized\n");
+                return -ENODEV;
+        }
+
+        if (acpi_check_region(piix4_smba, SMBIOSIZE, piix4_driver.name))
+                return -ENODEV;
+
+        if (!request_region(piix4_smba, SMBIOSIZE, piix4_driver.name)) {
+                dev_err(&PIIX4_dev->dev, "Auxiliary SMBus region 0x%x "
+                        "already in use!\n", piix4_smba);
+                return -EBUSY;
+        }
+
+        dev_info(&PIIX4_dev->dev,
+                 "Auxiliary SMBus Host Controller at 0x%x\n",
+                 piix4_smba);
+
+        return piix4_smba;
+}
+
 static int piix4_transaction(struct i2c_adapter *piix4_adapter)
 {
         struct i2c_piix4_adapdata *adapdata = i2c_get_adapdata(piix4_adapter);
@@ -497,6 +538,7 @@ static DEFINE_PCI_DEVICE_TABLE(piix4_ids) = {
 MODULE_DEVICE_TABLE (pci, piix4_ids);
 
 static struct i2c_adapter *piix4_main_adapter;
+static struct i2c_adapter *piix4_aux_adapter;
 
 static int __devinit piix4_add_adapter(struct pci_dev *dev,
                                         unsigned short smba,
@@ -560,10 +602,28 @@ static int __devinit piix4_probe(struct pci_dev *dev,
         else
                 retval = piix4_setup(dev, id);
 
+        /* If no main SMBus found, give up */
         if (retval < 0)
                 return retval;
 
-        return piix4_add_adapter(dev, retval, &piix4_main_adapter);
+        /* Try to register main SMBus adapter, give up if we can't */
+        retval = piix4_add_adapter(dev, retval, &piix4_main_adapter);
+        if (retval < 0)
+                return retval;
+
+        /* Check for auxiliary SMBus on some AMD chipsets */
+        if (dev->vendor == PCI_VENDOR_ID_ATI &&
+            dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
+            dev->revision < 0x40) {
+                retval = piix4_setup_aux(dev, id, 0x58);
+                if (retval > 0) {
+                        /* Try to add the aux adapter if it exists,
+                         * piix4_add_adapter will clean up if this fails */
+                        piix4_add_adapter(dev, retval, &piix4_aux_adapter);
+                }
+        }
+
+        return 0;
 }
 
 static void __devexit piix4_adap_remove(struct i2c_adapter *adap)
@@ -584,6 +644,11 @@ static void __devexit piix4_remove(struct pci_dev *dev)
                 piix4_adap_remove(piix4_main_adapter);
                 piix4_main_adapter = NULL;
         }
+
+        if (piix4_aux_adapter) {
+                piix4_adap_remove(piix4_aux_adapter);
+                piix4_aux_adapter = NULL;
+        }
 }
 
 static struct pci_driver piix4_driver = {