In order to support half-duplex operation at 10M and 100M link speeds, the
PHY collision detection signal (COL) should be routed to ICSSG
GPIO pin (PRGx_PRU0/1_GPI10) so that firmware can detect collision signal
and apply the CSMA/CD algorithm applicable for half duplex operation. A DT
property, "ti,half-duplex-capable" is introduced for this purpose. If
board has PHY COL pin conencted to PRGx_PRU1_GPIO10, this DT property can
be added to eth node of ICSSG, MII port to support half duplex operation at
that port.

Reviewed-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
---
 Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml b/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
index 311c570165f9..bba17d4d5874 100644
--- a/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
+++ b/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
@@ -106,6 +106,13 @@ properties:
               phandle to system controller node and register offset
               to ICSSG control register for RGMII transmit delay
 
+          ti,half-duplex-capable:
+            type: boolean
+            description:
+              Enable half duplex operation on ICSSG MII port. This requires
+              PHY output pin (COL) to be routed to ICSSG GPIO pin
+              (PRGx_PRU0/1_GPIO10) as input.
+
         required:
           - reg
     anyOf:
-- 
2.34.1

On Mon, Sep 11, 2023 at 11:31:59AM +0530, MD Danish Anwar wrote:
> In order to support half-duplex operation at 10M and 100M link speeds, the
> PHY collision detection signal (COL) should be routed to ICSSG
> GPIO pin (PRGx_PRU0/1_GPI10) so that firmware can detect collision signal
> and apply the CSMA/CD algorithm applicable for half duplex operation. A DT
> property, "ti,half-duplex-capable" is introduced for this purpose. If
> board has PHY COL pin conencted to PRGx_PRU1_GPIO10, this DT property can

nit: connected

...

On Mon, Sep 11, 2023 at 11:31:59AM +0530, MD Danish Anwar wrote:
> In order to support half-duplex operation at 10M and 100M link speeds, the
> PHY collision detection signal (COL) should be routed to ICSSG
> GPIO pin (PRGx_PRU0/1_GPI10) so that firmware can detect collision signal
> and apply the CSMA/CD algorithm applicable for half duplex operation. A DT
> property, "ti,half-duplex-capable" is introduced for this purpose. If
> board has PHY COL pin conencted to PRGx_PRU1_GPIO10, this DT property can
> be added to eth node of ICSSG, MII port to support half duplex operation at
> that port.
> 
> Reviewed-by: Roger Quadros <rogerq@kernel.org>
> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
> ---
>  Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml b/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
> index 311c570165f9..bba17d4d5874 100644
> --- a/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
> +++ b/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
> @@ -106,6 +106,13 @@ properties:
>                phandle to system controller node and register offset
>                to ICSSG control register for RGMII transmit delay
>  
> +          ti,half-duplex-capable:
> +            type: boolean
> +            description:
> +              Enable half duplex operation on ICSSG MII port. This requires

Still have capable vs. enable confusion. Please reword the description.

> +              PHY output pin (COL) to be routed to ICSSG GPIO pin
> +              (PRGx_PRU0/1_GPIO10) as input.
> +
>          required:
>            - reg
>      anyOf:
> -- 
> 2.34.1
>

On 11/09/23 22:16, Rob Herring wrote:
> On Mon, Sep 11, 2023 at 11:31:59AM +0530, MD Danish Anwar wrote:
>> In order to support half-duplex operation at 10M and 100M link speeds, the
>> PHY collision detection signal (COL) should be routed to ICSSG
>> GPIO pin (PRGx_PRU0/1_GPI10) so that firmware can detect collision signal
>> and apply the CSMA/CD algorithm applicable for half duplex operation. A DT
>> property, "ti,half-duplex-capable" is introduced for this purpose. If
>> board has PHY COL pin conencted to PRGx_PRU1_GPIO10, this DT property can
>> be added to eth node of ICSSG, MII port to support half duplex operation at
>> that port.
>>
>> Reviewed-by: Roger Quadros <rogerq@kernel.org>
>> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
>> ---
>>  Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml b/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
>> index 311c570165f9..bba17d4d5874 100644
>> --- a/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
>> +++ b/Documentation/devicetree/bindings/net/ti,icssg-prueth.yaml
>> @@ -106,6 +106,13 @@ properties:
>>                phandle to system controller node and register offset
>>                to ICSSG control register for RGMII transmit delay
>>  
>> +          ti,half-duplex-capable:
>> +            type: boolean
>> +            description:
>> +              Enable half duplex operation on ICSSG MII port. This requires
> 
> Still have capable vs. enable confusion. Please reword the description.
> 

Sure Rob, I will change the description to below.

    description:
      Indicates that the PHY output pin (COL) is routed to ICSSG GPIO
      pin (PRGx_PRU0/1_GPIO10) as input and ICSSG MII port is capable
      of half duplex operations.

Please let me know if this looks OK or if any other change is required.

>> +              PHY output pin (COL) to be routed to ICSSG GPIO pin
>> +              (PRGx_PRU0/1_GPIO10) as input.
>> +
>>          required:
>>            - reg
>>      anyOf:
>> -- 
>> 2.34.1
>>

-- 
Thanks and Regards,
Danish

> Sure Rob, I will change the description to below.
> 
>     description:
>       Indicates that the PHY output pin (COL) is routed to ICSSG GPIO

The PHY has multiple output pins, so i would not put COL in brackets,
but make it explicit which pin you are referring to.

>       pin (PRGx_PRU0/1_GPIO10) as input and ICSSG MII port is capable
>       of half duplex operations.

"input and so the ICSSG MII port is"

       Andrew

On 12/09/23 20:46, Andrew Lunn wrote:
>> Sure Rob, I will change the description to below.
>>
>>     description:
>>       Indicates that the PHY output pin (COL) is routed to ICSSG GPIO
> 
> The PHY has multiple output pins, so i would not put COL in brackets,
> but make it explicit which pin you are referring to.
> 

Sure, I will remove the brackets and make it explicit.

>>       pin (PRGx_PRU0/1_GPIO10) as input and ICSSG MII port is capable
>>       of half duplex operations.
> 
> "input and so the ICSSG MII port is"
> 

I think "input so that the ICSSG MII port is" will be better.

The description would look something like below,

  description:
    Indicates that the PHY output pin COL is routed to ICSSG GPIO pin
    (PRGx_PRU0/1_GPIO10) as input so that the ICSSG MII port is
    capable of half duplex operations.

I will post the next version with this change.

>        Andrew

-- 
Thanks and Regards,
Danish