Re: [PATCH v1 05/20] ARM: dts: imx6qdl: use enet_clk_ref instead of enet_out for the FEC node

[Peng Fan <peng.fan@oss.nxp.com>]

On 1/16/2023 1:26 PM, Oleksij Rempel wrote:
> On Mon, Jan 16, 2023 at 09:01:08AM +0800, Peng Fan wrote:
>> Hi Oleksij,
>>
>> On 1/13/2023 10:27 PM, Oleksij Rempel wrote:
>>> Old imx6q machine code makes RGMII/RMII clock direction decision based on
>>> configuration of "ptp" clock. "enet_out" is not used and make no real
>>> sense, since we can't configure it as output or use it as clock
>>> provider.
>>>
>>> Instead of "enet_out" use "enet_clk_ref" which is actual selector to
>>> choose between internal and external clock source:
>>>
>>> FEC MAC <---------- enet_clk_ref <--------- SoC PLL
>>>                            \
>>> 			  ^------<-> refclock PAD (bi directional)
>>>
>>> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
>>> ---
>>>    arch/arm/boot/dts/imx6qdl.dtsi | 4 ++--
>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
>>> index ff1e0173b39b..71522263031a 100644
>>> --- a/arch/arm/boot/dts/imx6qdl.dtsi
>>> +++ b/arch/arm/boot/dts/imx6qdl.dtsi
>>> @@ -1050,8 +1050,8 @@ fec: ethernet@2188000 {
>>>    				clocks = <&clks IMX6QDL_CLK_ENET>,
>>>    					 <&clks IMX6QDL_CLK_ENET>,
>>>    					 <&clks IMX6QDL_CLK_ENET_REF>,
>>> -					 <&clks IMX6QDL_CLK_ENET_REF>;
>>> -				clock-names = "ipg", "ahb", "ptp", "enet_out";
>>> +					 <&clks IMX6QDL_CLK_ENET_REF_SEL>;
>>> +				clock-names = "ipg", "ahb", "ptp", "enet_clk_ref";
>>
>>
>> Please also update fec binding, otherwise there will be dtbs check error.
> 
> Hm, there is no restriction on enet_clk_ref use or requirements to use
> enet_out in Documentation/devicetree/bindings/net/fsl,fec.yaml
> 
> Do I missing something?

After check, seems using enet_out would trigger dtbs_check error, using
enet_clk_ref would not as what you did in this patch. So your patch is fine.

   clock-names:
     minItems: 2
     maxItems: 5
     items:
       enum:
         - ipg
         - ahb
         - ptp
         - enet_clk_ref
         - enet_out
         - enet_2x_txclk

Regards,
Peng.


> 
> Regards,
> Oleksij