[PATCH] i2c: core: make it possible to match a pure device tree driver

[Linus Walleij]

On Mon, May 13, 2013 at 9:16 AM, Sascha Hauer <s.hauer at pengutronix.de> wrote:

>> -     status = driver->probe(client, i2c_match_id(driver->id_table, client));
>> +     if (dev->driver->of_match_table)
>> +             /* Device tree matching */
>> +             status = driver->probe(client, NULL);
>> +     else
>> +             /* Fall back to matching the id_table */
>> +             status = driver->probe(client, i2c_match_id(driver->id_table, client));
>
> If you correctly register a device with "vendor,product" in the devicetree
> the driver can already fetch the of_device_id using of_match_device(dt_ids, &client->dev)
> just like a platform driver would do aswell.

Yes, this is what I write in the commit message:

  "(...) If the driver wants to deduce secondary info
  from the struct of_device_id .data field, it has to call
  of_match_device() on its own match table in the probe function
  device tree probe path."

> i2c_match_id will return a NULL pointer if called with "vendor,product",
> because nothing matches in the drivers id_table, so for this case you
> change nothing.
>
> If anything, you introduce the problem that a devicetree capable driver
> no longer gets a i2c_device_id if the device was instantiated with
> i2c_board_info.

Hm, you're right there, what about this:

+     if (dev->of_node)
+             /* Device tree matching */
+             status = driver->probe(client, NULL);
+     else
+             /* Fall back to matching the id_table */
+             status = driver->probe(client,
i2c_match_id(driver->id_table, client));

If the device has an of_node it surely should not be using the
id_table and it'd be correct to pass NULL, right?

Yours,
Linus Walleij