Re: [PATCH net-next v12 07/14] dpll: zl3073x: Add clock_id field

[Jiri Pirko]

Wed, Jul 02, 2025 at 01:43:38PM +0200, ivecera@xxxxxxxxxx wrote:
>
>On 02. 07. 25 12:31 odp., Jiri Pirko wrote:
>> Sun, Jun 29, 2025 at 09:10:42PM +0200, ivecera@xxxxxxxxxx wrote:
>> > Add .clock_id to zl3073x_dev structure that will be used by later
>> > commits introducing DPLL feature. The clock ID is required for DPLL
>> > device registration.
>> > 
>> > To generate this ID, use chip ID read during device initialization.
>> > In case where multiple zl3073x based chips are present, the chip ID
>> > is shifted and lower bits are filled by an unique value - using
>> > the I2C device address for I2C connections and the chip-select value
>> > for SPI connections.
>> 
>> You say that multiple chips may have the same chip ID? How is that
>> possible? Isn't it supposed to be unique?
>> I understand clock ID to be invariant regardless where you plug your
>> device. When you construct it from i2c address, sounds wrong.
>
>The chip id is not like serial number but it is like device id under
>PCI. So if you will have multiple chips with this chip id you have to
>distinguish somehow between them, this is the reason why I2C address
>is added into the final value.
>
>Anyway this device does not have any attribute that corresponds to
>clock id (as per our previous discussion) and it will be better to NOT
>require clock id from DPLL core side.

Yes, better not to require it comparing to having it wrong.

>
>Ivan
>
>