Re: [PATCH net-next 2/2] net: phy: air_en8811h: Add the Airoha EN8811H PHY driver

[Eric Woudstra <ericwouds@gmail.com>]

Hi Russell,

>> Searching the driver for "air_buckpbus_reg_read", there are four
>> instances where you read-modify-write, and only one instance which is
>> just a read.
>>
>> I wonder whether it would make more sense to structure the accessors as
>>
>> 	__air_buckpbus_set_address(phydev, addr)
>> 	__air_buckpbus_read(phydev, *data)
>> 	__air_buckpbus_write(phydev, data)
>>
>> which would make implementing reg_read, reg_write and reg_modify()
>> easier, and the addition of reg_modify() means that (a) there are less
>> bus cycles (through having to set the address twice) and (b) ensures
>> that the read-modify-write can be done atomically on the bus. This
>> assumes that reading data doesn't auto-increment the address (which
>> you would need to check.)
> 
> I will see if I can change the code to:
> 
>         __air_buckpbus_set_address(phydev, addr)
>         __air_buckpbus_read(phydev, *data)
>         __air_buckpbus_write(phydev, data)
>         air_buckpbus_reg_read()
>         air_buckpbus_reg_write()
>         air_buckpbus_reg_modify()
> 
> While not changing (except if (saved_page >= 0)):
> 
>         __air_write_buf()
>         air_write_buf()
> 

I just remember, the address register for write, is a different
register from the address register for read. So we always have
to write to address registers twice.

I can still implement an atomic air_buckpbus_reg_modify() though.

Best regards,

Eric Woudstra