[PATCH v5 1/1] dt-bindings: net: dwmac: Document STM32 property st,ext-phyclk

[Christophe ROULLIER]

On 3/30/24 19:40, Krzysztof Kozlowski wrote:
> On 28/03/2024 15:08, Christophe Roullier wrote:
>> The Linux kernel dwmac-stm32 driver currently supports three DT
>> properties used to configure whether PHY clock are generated by
>> the MAC or supplied to the MAC from the PHY.
>>
>> Originally there were two properties, st,eth-clk-sel and
>> st,eth-ref-clk-sel, each used to configure MAC clocking in
>> different bus mode and for different MAC clock frequency.
>> Since it is possible to determine the MAC 'eth-ck' clock
>> frequency from the clock subsystem and PHY bus mode from
>> the 'phy-mode' property, two disparate DT properties are
>> no longer required to configure MAC clocking.
>>
>> Linux kernel commit 1bb694e20839 ("net: ethernet: stmmac: simplify phy modes management for stm32")
>> introduced a third, unified, property st,ext-phyclk. This property
>> covers both use cases of st,eth-clk-sel and st,eth-ref-clk-sel DT
>> properties, as well as a new use case for 25 MHz clock generated
>> by the MAC.
>>
>> The third property st,ext-phyclk is so far undocumented,
>> document it.
>>
>> Below table summarizes the clock requirement and clock sources for
>> supported PHY interface modes.
>>   __________________________________________________________________________
>> |PHY_MODE | Normal | PHY wo crystal|   PHY wo crystal   |No 125Mhz from PHY|
>> |         |        |      25MHz    |        50MHz       |                  |
>>
>> ---------------------------------------------------------------------------
>> |  MII    |    -   |     eth-ck    |        n/a         |       n/a        |
>> |         |        | st,ext-phyclk |                    |                  |
>>
>> ---------------------------------------------------------------------------
>> |  GMII   |    -   |     eth-ck    |        n/a         |       n/a        |
>> |         |        | st,ext-phyclk |                    |                  |
>>
>> ---------------------------------------------------------------------------
>> | RGMII   |    -   |     eth-ck    |        n/a         |      eth-ck      |
>> |         |        | st,ext-phyclk |                    | st,eth-clk-sel or|
>> |         |        |               |                    | st,ext-phyclk    |
>>
>> ---------------------------------------------------------------------------
>> | RMII    |    -   |     eth-ck    |      eth-ck        |       n/a        |
>> |         |        | st,ext-phyclk | st,eth-ref-clk-sel |                  |
>> |         |        |               | or st,ext-phyclk   |                  |
>>
>> ---------------------------------------------------------------------------
>>
>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski at linaro.org>
>> Signed-off-by: Christophe Roullier <christophe.roullier at foss.st.com>
> Can you please start testing patches *before* sending them?
Yes sorry, when I removed patch with phy-supply property (1/2), I had 
conflict merge and I did not pay attention that my commit was modified :-(
>
> Best regards,
> Krzysztof
>