1 files changed, 13 insertions, 3 deletions

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 08847e8b8998..eb3627f35d12 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -146,6 +146,7 @@
 #define SMBHSTCFG_HST_EN        1
 #define SMBHSTCFG_SMB_SMI_EN    2
 #define SMBHSTCFG_I2C_EN        4
+#define SMBHSTCFG_SPD_WD        0x10
 
 /* TCO configuration bits for TCOCTL */
 #define TCOCTL_EN               0x0100
@@ -865,9 +866,16 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
                 block = 1;
                 break;
         case I2C_SMBUS_I2C_BLOCK_DATA:
-                /* NB: page 240 of ICH5 datasheet shows that the R/#W
-                 * bit should be cleared here, even when reading */
-                outb_p((addr & 0x7f) << 1, SMBHSTADD(priv));
+                /*
+                 * NB: page 240 of ICH5 datasheet shows that the R/#W
+                 * bit should be cleared here, even when reading.
+                 * However if SPD Write Disable is set (Lynx Point and later),
+                 * the read will fail if we don't set the R/#W bit.
+                 */
+                outb_p(((addr & 0x7f) << 1) |
+                       ((priv->original_hstcfg & SMBHSTCFG_SPD_WD) ?
+                        (read_write & 0x01) : 0),
+                       SMBHSTADD(priv));
                 if (read_write == I2C_SMBUS_READ) {
                         /* NB: page 240 of ICH5 datasheet also shows
                          * that DATA1 is the cmd field when reading */
@@ -1573,6 +1581,8 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
                 /* Disable SMBus interrupt feature if SMBus using SMI# */
                 priv->features &= ~FEATURE_IRQ;
         }
+        if (temp & SMBHSTCFG_SPD_WD)
+                dev_info(&dev->dev, "SPD Write Disable is set\n");
 
         /* Clear special mode bits */
         if (priv->features & (FEATURE_SMBUS_PEC | FEATURE_BLOCK_BUFFER))