i2c: i801: Fix I2C Block Read on 8-Series/C220 and later

[platform/kernel/linux-starfive.git] / drivers / i2c / busses / i2c-i801.c

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 26298af..eb3627f 100644 (file)
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -64,6 +64,7 @@
  * Broxton (SOC)               0x5ad4  32      hard    yes     yes     yes
  * Lewisburg (PCH)             0xa1a3  32      hard    yes     yes     yes
  * Lewisburg Supersku (PCH)    0xa223  32      hard    yes     yes     yes
+ * Kaby Lake PCH-H (PCH)       0xa2a3  32      hard    yes     yes     yes
  *
  * Features supported by this driver:
  * Software PEC                                no
@@ -145,6 +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
@@ -226,6 +228,7 @@
 #define PCI_DEVICE_ID_INTEL_SUNRISEPOINT_H_SMBUS       0xa123
 #define PCI_DEVICE_ID_INTEL_LEWISBURG_SMBUS            0xa1a3
 #define PCI_DEVICE_ID_INTEL_LEWISBURG_SSKU_SMBUS       0xa223
+#define PCI_DEVICE_ID_INTEL_KABYLAKE_PCH_H_SMBUS       0xa2a3
 
 struct i801_mux_config {
        char *gpio_chip;
@@ -863,9 +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 */
@@ -1006,6 +1016,7 @@ static const struct pci_device_id i801_ids[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BROXTON_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_LEWISBURG_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_LEWISBURG_SSKU_SMBUS) },
+       { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_KABYLAKE_PCH_H_SMBUS) },
        { 0, }
 };
 
@@ -1482,6 +1493,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
        case PCI_DEVICE_ID_INTEL_LEWISBURG_SMBUS:
        case PCI_DEVICE_ID_INTEL_LEWISBURG_SSKU_SMBUS:
        case PCI_DEVICE_ID_INTEL_DNV_SMBUS:
+       case PCI_DEVICE_ID_INTEL_KABYLAKE_PCH_H_SMBUS:
                priv->features |= FEATURE_I2C_BLOCK_READ;
                priv->features |= FEATURE_IRQ;
                priv->features |= FEATURE_SMBUS_PEC;
@@ -1569,6 +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))
@@ -1615,7 +1629,6 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
                "SMBus I801 adapter at %04lx", priv->smba);
        err = i2c_add_adapter(&priv->adapter);
        if (err) {
-               dev_err(&dev->dev, "Failed to add SMBus adapter\n");
                i801_acpi_remove(priv);
                return err;
        }