[PATCH 1/4] i2c: Share the I2C device presence detection code

[Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>]

Use the same I2C device presence detection code for legacy and new
device detection functions. This is more consistent and makes the code
smaller.

Signed-off-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
Cc: Matthieu Castet <castet.matthieu-GANU6spQydw@public.gmane.org>
---
Matthieu, are you happier that way?

 drivers/i2c/i2c-core.c |   33 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

--- linux-2.6.34-rc3.orig/drivers/i2c/i2c-core.c	2010-04-08 09:51:04.000000000 +0200
+++ linux-2.6.34-rc3/drivers/i2c/i2c-core.c	2010-04-08 09:51:08.000000000 +0200
@@ -1277,8 +1277,11 @@ EXPORT_SYMBOL(i2c_master_recv);
  * 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 in that case too.
+ * 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.
+ * 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)
@@ -1286,6 +1289,13 @@ static int i2c_default_probe(struct i2c_
 	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,
@@ -1317,23 +1327,8 @@ static int i2c_detect_address(struct i2c
 		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));


-- 
Jean Delvare