Re: [PATCH v1 1/2] dt-bindings: i2c: exynos5: Add samsung,exynos8895-hsi2c compatible

[Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>]

On 12/17/24 11:43, Krzysztof Kozlowski wrote:
> On 17/12/2024 10:31, Ivaylo Ivanov wrote:
>> On 12/17/24 11:26, Krzysztof Kozlowski wrote:
>>> On 17/12/2024 10:08, Ivaylo Ivanov wrote:
>>>>>>>>        - items:
>>>>>>>>            - enum:
>>>>>>>> @@ -94,9 +95,28 @@ allOf:
>>>>>>>>          - clock-names
>>>>>>>>  
>>>>>>>>      else:
>>>>>>>> -      properties:
>>>>>>>> -        clocks:
>>>>>>>> -          maxItems: 1
>>>>>>>> +      if:
>>>>>>>> +        properties:
>>>>>>>> +          compatible:
>>>>>>>> +            contains:
>>>>>>>> +              enum:
>>>>>>>> +                - samsung,exynos8895-hsi2c
>>>>>>>> +
>>>>>>>> +      then:
>>>>>>>> +        properties:
>>>>>>>> +          clocks:
>>>>>>> Missing minItems
>>>>>>>
>>>>>>>> +            maxItems: 2
>>>>>>>> +
>>>>>>>> +          clock-names:
>>>>>>> Ditto
>>>>>>>
>>>>>>>> +            maxItems: 2
>>>>>>>> +
>>>>>>>> +        required:
>>>>>>>> +          - clock-names
>>>>>>> I don't understand why do you need second, same branch in if, basically
>>>>>> Because, as I stated in the commit message, we have HSI2C controllers
>>>>>> both implemented in USIv1 blocks and outside. These that are a part of
>>>>> On Exynos8895? Where? With the same compatible?
>>>> hsi2c_0 which has a clock from BUSC and hsi2c_1 to hsi2c_4 which use clocks
>>>> from PERIC1 (CLK_GOUT_PERIC1_HSI2C_CAM{0,1,2,3}_IPCLK). Why would
>>>> they need a different compatible though? It's functionally the same i2c design
>>>> as the one implemented in USIv1 blocks.
>>> If one block is part of USI and other not, they might not be the same
>>> I2C blocks, even if interface is similar. If they were the same or even
>>> functionally the same, they would have the same clock inputs. However
>> I see, so in such case I should make samsung,exynos8895-hsi2c-nonusi or
>> something like that?
>>
>>> user manual also suggests that there is only one clock, not two (for
>>> both cases), so they could be functionally equivalent but then number of
>>> clocks looks incorrect.
>> That'd be weird. Both according to downstream and upstream clk driver,
>> for the USI-implemented i2cs we have a pclk and an sclk_usi.
> Something is not precise here, as usually with Samsung clock topology.
>
> First, the non-USI instances have the IPCLK as well, e.g. things like
> PERIC1_UID_HSI2C_CAM1_IPCLKPORT_iPCLK
>
> USI have BLK_PERIC0_UID_USI03_IPCLKPORT_i_SCLK_USI, but that's USI
> clock, not HSI2C in USI. Datasheet mentions this is UART and SPI special
> clock, but not I2C.

That's weird. Don't we need the clock enabled in order for the
USIv1's HSI2C to work?

Best regards,
Ivo

>  The PCLK is used for HSI2C iPCLK.
>
>
> Best regards,
> Krzysztof