i2c: piix4: Support alternative port selection register

[cascardo/linux.git] / drivers / i2c / busses / i2c-piix4.c

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 93f2895..78d4483 100644 (file)
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -85,8 +85,14 @@
 /* SB800 constants */
 #define SB800_PIIX4_SMB_IDX            0xcd6
 
-/* SB800 port is selected by bits 2:1 of the smb_en register (0x2c) */
+/*
+ * SB800 port is selected by bits 2:1 of the smb_en register (0x2c)
+ * or the smb_sel register (0x2e), depending on bit 0 of register 0x2f.
+ * Hudson-2/Bolton port is always selected by bits 2:1 of register 0x2f.
+ */
 #define SB800_PIIX4_PORT_IDX           0x2c
+#define SB800_PIIX4_PORT_IDX_ALT       0x2e
+#define SB800_PIIX4_PORT_IDX_SEL       0x2f
 #define SB800_PIIX4_PORT_IDX_MASK      0x06
 
 /* insmod parameters */
@@ -136,8 +142,13 @@ static const struct dmi_system_id piix4_dmi_ibm[] = {
        { },
 };
 
-/* SB800 globals */
+/*
+ * SB800 globals
+ * piix4_mutex_sb800 protects piix4_port_sel_sb800 and the pair
+ * of I/O ports at SB800_PIIX4_SMB_IDX.
+ */
 static DEFINE_MUTEX(piix4_mutex_sb800);
+static u8 piix4_port_sel_sb800;
 static const char *piix4_main_port_names_sb800[PIIX4_MAX_ADAPTERS] = {
        " port 0", " port 2", " port 3", " port 4"
 };
@@ -254,7 +265,7 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
                             const struct pci_device_id *id, u8 aux)
 {
        unsigned short piix4_smba;
-       u8 smba_en_lo, smba_en_hi, smb_en, smb_en_status;
+       u8 smba_en_lo, smba_en_hi, smb_en, smb_en_status, port_sel;
        u8 i2ccfg, i2ccfg_offset = 0x10;
 
        /* SB800 and later SMBus does not support forcing address */
@@ -334,6 +345,23 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
                 "SMBus Host Controller at 0x%x, revision %d\n",
                 piix4_smba, i2ccfg >> 4);
 
+       /* Find which register is used for port selection */
+       if (PIIX4_dev->vendor == PCI_VENDOR_ID_AMD) {
+               piix4_port_sel_sb800 = SB800_PIIX4_PORT_IDX_ALT;
+       } else {
+               mutex_lock(&piix4_mutex_sb800);
+               outb_p(SB800_PIIX4_PORT_IDX_SEL, SB800_PIIX4_SMB_IDX);
+               port_sel = inb_p(SB800_PIIX4_SMB_IDX + 1);
+               piix4_port_sel_sb800 = (port_sel & 0x01) ?
+                                      SB800_PIIX4_PORT_IDX_ALT :
+                                      SB800_PIIX4_PORT_IDX;
+               mutex_unlock(&piix4_mutex_sb800);
+       }
+
+       dev_info(&PIIX4_dev->dev,
+                "Using register 0x%02x for SMBus port selection\n",
+                (unsigned int)piix4_port_sel_sb800);
+
        return piix4_smba;
 }
 
@@ -563,7 +591,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
 
        mutex_lock(&piix4_mutex_sb800);
 
-       outb_p(SB800_PIIX4_PORT_IDX, SB800_PIIX4_SMB_IDX);
+       outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
        smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
 
        port = adapdata->port;