[RFC, 2.6.26.3-rc1] i2c: Fix NULL pointer dereference in i2c_new_probed_device

[Oliver Pinter <oliver.pntr@gmail.com>]

>From b25b791b13aaa336b56c4f9bd417ff126363f80b Mon Sep 17 00:00:00 2001
It is an RFC for sending this patch for stable, when this patch needed, then send ACK and CC stable,
 if not then send NAK.

---

From: Hans Verkuil <hverkuil@xs4all.nl>
Date: Sun, 10 Aug 2008 22:56:15 +0200
Subject: [PATCH] i2c: Fix NULL pointer dereference in i2c_new_probed_device

Fix a NULL pointer dereference that happened when calling
i2c_new_probed_device on one of the addresses for which we use byte
reads instead of quick write for detection purpose (that is: 0x30-0x37
and 0x50-0x5f).

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
CC: Oliver Pinter <oliver.pntr@gmail.com>

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 7bf38c4..c16dcad 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1451,9 +1451,11 @@ i2c_new_probed_device(struct i2c_adapter *adap,
 		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, NULL) >= 0)
+					   I2C_SMBUS_BYTE, &data) >= 0)
 				break;
 		} else {
 			if (i2c_smbus_xfer(adap, addr_list[i], 0,