1 files changed, 40 insertions, 40 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index e0f833cca3f1..f744f73e3ff5 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1277,6 +1277,41 @@ EXPORT_SYMBOL(i2c_master_recv);
  * ----------------------------------------------------
  */
 
+/*
+ * Legacy default probe function, mostly relevant for SMBus. The default
+ * probe method is a quick write, but it is known to corrupt the 24RF08
+ * EEPROMs due to a state machine bug, and could also irreversibly
+ * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
+ * we use a short byte read instead. Also, some bus drivers don't implement
+ * quick write, so we fallback to a byte read in that case too.
+ * On x86, there is another special case for FSC hardware monitoring chips,
+ * which want regular byte reads (address 0x73.) Fortunately, these are the
+ * only known chips using this I2C address on PC hardware.
+ * Returns 1 if probe succeeded, 0 if not.
+ */
+static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
+{
+        int err;
+        union i2c_smbus_data dummy;
+
+#ifdef CONFIG_X86
+        if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
+         && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
+                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
+                                     I2C_SMBUS_BYTE_DATA, &dummy);
+        else
+#endif
+        if ((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50
+         || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
+                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
+                                     I2C_SMBUS_BYTE, &dummy);
+        else
+                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
+                                     I2C_SMBUS_QUICK, NULL);
+
+        return err >= 0;
+}
+
 static int i2c_detect_address(struct i2c_client *temp_client,
                               struct i2c_driver *driver)
 {
@@ -1297,23 +1332,8 @@ static int i2c_detect_address(struct i2c_client *temp_client,
                 return 0;
 
         /* Make sure there is something at this address */
-        if (addr == 0x73 && (adapter->class & I2C_CLASS_HWMON)) {
-                /* Special probe for FSC hwmon chips */
-                union i2c_smbus_data dummy;
-
-                if (i2c_smbus_xfer(adapter, addr, 0, I2C_SMBUS_READ, 0,
-                                   I2C_SMBUS_BYTE_DATA, &dummy) < 0)
-                        return 0;
-        } else {
-                if (i2c_smbus_xfer(adapter, addr, 0, I2C_SMBUS_WRITE, 0,
-                                   I2C_SMBUS_QUICK, NULL) < 0)
-                        return 0;
-
-                /* Prevent 24RF08 corruption */
-                if ((addr & ~0x0f) == 0x50)
-                        i2c_smbus_xfer(adapter, addr, 0, I2C_SMBUS_WRITE, 0,
-                                       I2C_SMBUS_QUICK, NULL);
-        }
+        if (!i2c_default_probe(adapter, addr))
+                return 0;
 
         /* Finally call the custom detection function */
         memset(&info, 0, sizeof(struct i2c_board_info));
@@ -1420,29 +1440,9 @@ i2c_new_probed_device(struct i2c_adapter *adap,
                         continue;
                 }
 
-                /* Test address responsiveness
-                   The default probe method is a quick write, but it is known
-                   to corrupt the 24RF08 EEPROMs due to a state machine bug,
-                   and could also irreversibly write-protect some EEPROMs, so
-                   for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte
-                   read instead. Also, some bus drivers don't implement
-                   quick write, so we fallback to a byte read it that case
-                   too. */
-                if ((addr_list[i] & ~0x07) == 0x30
-                 || (addr_list[i] & ~0x0f) == 0x50
-                 || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) {
-                        union i2c_smbus_data data;
-
-                        if (i2c_smbus_xfer(adap, addr_list[i], 0,
-                                           I2C_SMBUS_READ, 0,
-                                           I2C_SMBUS_BYTE, &data) >= 0)
-                                break;
-                } else {
-                        if (i2c_smbus_xfer(adap, addr_list[i], 0,
-                                           I2C_SMBUS_WRITE, 0,
-                                           I2C_SMBUS_QUICK, NULL) >= 0)
-                                break;
-                }
+                /* Test address responsiveness */
+                if (i2c_default_probe(adap, addr_list[i]))
+                        break;
         }
 
         if (addr_list[i] == I2C_CLIENT_END) {