[alsa-devel] [PATCH v2 5/5] ASoC: WM8903: Add device tree binding

Stephen Warren swarren at nvidia.com
Tue Dec 6 19:22:24 CET 2011

Stephen Warren wrote at Friday, December 02, 2011 3:09 PM:
> Document the device tree binding for the WM8903 codec, and modify the
> driver to extract platform data from the device tree, if present.


I just realized that when I was re-organizing all the WM8903 patches, I
dropped the part that added the of_match table to the driver:

+static const struct of_device_id wm8903_of_match[] __devinitconst = {
+	{ .compatible = "wlf,wm8903", },
+	{},
+MODULE_DEVICE_TABLE(of, wm8903_of_match);

Now, everything still works without this. Looking at the Linux OF code,
it works by retrieving the compatible property, taking everything after
the comma if present, and then creating an i2c_board_info with that
type, which in this case is "wm8903" and matches wm8903.c's i2c_device_id
table. See drivers/of/of_i2c.c:of_i2c_register_devices() and the call to

So, the question is: Should I go back and add the of_match table, or
is I2C intended to work without it perpetually? I notice that you added
an of_match table for all the other WM codecs.



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