Am 2013-12-05 18:40, schrieb Stephen Warren:

On 12/05/2013 10:43 AM, Stefan Agner wrote:

quoted

Am 2013-12-05 18:06, schrieb Stephen Warren:
<snip>

quoted

quoted

@@ -493,13 +527,12 @@ static int tps6586x_i2c_probe(struct i2c_client *client,
 		return -EIO;
 	}

-	dev_info(&client->dev, "VERSIONCRC is %02x\n", ret);
-
 	tps6586x = devm_kzalloc(&client->dev, sizeof(*tps6586x), GFP_KERNEL);
-	if (tps6586x == NULL) {
-		dev_err(&client->dev, "memory for tps6586x alloc failed\n");
+	if (!tps6586x)
 		return -ENOMEM;
-	}
+
+	tps6586x->version = ret;

I have to say, I dislike this version of the patch. Separating the
reading of the version register from the assignment to tps6586x->version
doesn't make any sense, especially given that the version value is
stored in a variable named "ret"; that name isn't remotely related to
what's stored there. What if someone comes along later and adds more
code that assigns to ret between where it's repurposed for the version
value and where it's assigned to tps6586x->version? It'd be extremely
difficult for a patch reviewer to spot that given the limited context in
a diff, and quite non-obvious to the person changing the code too..

The value comes from the return value of i2c_smbus_read_byte_data. If
the value is below zero its an EIO error.

I could add a variable "version", but for me it felt strange because we
check if version is below zero. This feels like its a wrong version
rather than a transmit error. So I would prefer ret over version. But I
agree, when one just reads the patch, its not obvious what exactly
happens.

In my opinion, using a variable named "version" here would be
preferable. Testing that against <0 is just the way the I2C API works,
so the same argument could be applied to any I2C access.

Hm, I try the empiric way:

$ grep -r -e i2c_smbus_read_byte_data | grep "ret =" | wc -l
139
$ grep -r -e i2c_smbus_read_byte_data | grep "version =" | wc -l
3

Ok, thats not fair at all, version is usage specific whilst ret is not.

$ grep -r -e i2c_smbus_read_byte_data | grep " = " | wc -l
703

On the other hand is the additional variable. But I think the compiler
will optimize that anyway, so this might not be an argument at all :-)

I see your point... Should I create another patch revision? Lee, is the
patch already merged?