On 05/04/2024 16:46, Frank Li wrote:
> On Fri, Apr 05, 2024 at 08:41:59AM +0200, Krzysztof Kozlowski wrote:
>> On 04/04/2024 18:19, Frank Li wrote:
>>> imx8qxp-mek use two kind audio codec, wm8960 and wm8962. Using dummy gpio
>>> i2c bus mux to connect both i2c devices. One will probe failure and other
>>> will probe success when devices driver check whoami. So one dtb can cover
>>> both board configuration.
>>
>> I don't understand it. Either you add real device or not. If one board
>> has two devices, then why do you need to check for failures?
>>
>> Anyway, don't add fake stuff to DTS.
>
> NAK can't resolve the problem. It should be common problem for long time
> cycle boards. Some chipes will be out life cycle. such as some sensor. So
> chips on boards have been replace by some pin to pin compatible sensor. For
> example:
> old boards: use sensor A with address 0x1a
> new bench: use sensor B with address 0x1b.
>
> You can treat it as two kind boards, RevA or RevB. But most user want to
> use one dtb to handle such small differences. For this case, it should be
> simple. Just add a super set.
> i2c
> {
> sensorA@1a
> {
> }
> sensorB@1b
> {
> }
> }
>
> It also depend on whoami check by i2c devices. Only A or B will probe.
>
> wm8960 and wm8962 are more complex example. wm8960 is out of life. But
> wm8962 and wm8960 have the same i2c address. The current i2c frame can't
> allow the same i2c address in one i2c bus.
>
> You are feel to NAK my method, but I hope you also provide constructive
> solution to help resolve the problem.
Yes, we resolved it long time ago. Your bootloader can (usually easily)
detect revision of the board and load appropriate DTS or DTS+DTSO.
Best regards,
Krzysztof
