Re: cs42xxc-i2c: i2c device and driver not connected through deivce-tree

[Peter Bergin <peter@xxxxxxxxxxxxxxxx>]

On 2022-10-17 23:19, Peter Bergin wrote:
> Hi,
>
> on my system I have a cs42448 chip connected on a i2c bus to a 
> i.Mx8mp. The chip is connected on i2c-2 with address 0x48 and I can 
> detect it and read registers with help of i2c-tools. Running kernel 
> v6.0 and having problem as the device and driver is not connected in 
> my system. The probe function (cs42xx8_i2c_probe) is never called 
> during initialization. The module is loaded in the kernel.
>
> Here is a snippet from the dtb file:
>
>     codec: cs42xx8@48 {
>         compatible = "cirrus,cs42448";
>         reg = <0x48>;
>         reset-gpios = <&gpio4 9 GPIO_ACTIVE_LOW>;
>         #sound-dai-cells = <0>;
>         clocks = <&audio_blk_ctrl IMX8MP_CLK_AUDIOMIX_SAI3_MCLK1>;
>         clock-names = "mclk";
>         VA-supply = <&reg_audio_pwr_5v0>;
>         VD-supply = <&reg_audio_pwr_3v3>;
>         VLS-supply = <&reg_audio_pwr_3v3>;
>         VLC-supply = <&reg_audio_pwr_3v3>;
>     };
>
> Tried to dig in to the code and understand why the device and the 
> driver is not connected with each other. I assumed that they should be 
> connected through device-tree.
>
> In sound/soc/codec/snd-soc-cs42xx8-i2c.mod.c:
>
> MODULE_ALIAS("i2c:cs42448");
> MODULE_ALIAS("i2c:cs42888");
>
> So there are no alias to of: in that file.
>
> Do I have the wrong assumption about connecting the device with the 
> driver through the device-tree? Something wrong in my dts snippet 
> above? Great if someone could help out with some ideas around this.
My problem is solved and I can connect device and driver with this patch:

diff --git a/sound/soc/codecs/cs42xx8-i2c.c b/sound/soc/codecs/cs42xx8-i2c.c
index cb06a06d48b0..6e8ee28d01f8 100644
--- a/sound/soc/codecs/cs42xx8-i2c.c
+++ b/sound/soc/codecs/cs42xx8-i2c.c
@@ -37,6 +37,13 @@ static int cs42xx8_i2c_remove(struct i2c_client *i2c)
        return 0;
 }

+const struct of_device_id cs42xx8_of_match[] = {
+       { .compatible = "cirrus,cs42448", .data = &cs42448_data, },
+       { .compatible = "cirrus,cs42888", .data = &cs42888_data, },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, cs42xx8_of_match);
+
 static struct i2c_device_id cs42xx8_i2c_id[] = {
        {"cs42448", (kernel_ulong_t)&cs42448_data},
        {"cs42888", (kernel_ulong_t)&cs42888_data},

That information is already present and copied from 
sound/soc/codecs/cs42xx8.c. Is this a suitable solution to the problem? 
Something that can be applied upstream?

Thanks,
/Peter