Re: [PATCH 4/4] dt-bindings: Document the DT bindings for lan78xx

[Phil Elwell <phil@raspberrypi.org>]

On 16/04/2018 20:22, Rob Herring wrote:
> On Thu, Apr 12, 2018 at 02:55:36PM +0100, Phil Elwell wrote:
>> The Microchip LAN78XX family of devices are Ethernet controllers with
>> a USB interface. Despite being discoverable devices it can be useful to
>> be able to configure them from Device Tree, particularly in low-cost
>> applications without an EEPROM or programmed OTP.
>>
>> Document the supported properties in a bindings file, adding it to
>> MAINTAINERS at the same time.
>>
>> Signed-off-by: Phil Elwell <phil@raspberrypi.org>
>> ---
>>  .../devicetree/bindings/net/microchip,lan78xx.txt  | 44 ++++++++++++++++++++++
>>  MAINTAINERS                                        |  1 +
>>  2 files changed, 45 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/net/microchip,lan78xx.txt
>>
>> diff --git a/Documentation/devicetree/bindings/net/microchip,lan78xx.txt b/Documentation/devicetree/bindings/net/microchip,lan78xx.txt
>> new file mode 100644
>> index 0000000..e7d7850
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/net/microchip,lan78xx.txt
>> @@ -0,0 +1,44 @@
>> +Microchip LAN78xx Gigabit Ethernet controller
>> +
>> +The LAN78XX devices are usually configured by programming their OTP or with
>> +an external EEPROM, but some platforms (e.g. Raspberry Pi 3 B+) have neither.
>> +
>> +Please refer to ethernet.txt for a description of common Ethernet bindings.
>> +
>> +Optional properties:
>> +- microchip,eee-enabled: if present, enable Energy Efficient Ethernet support;
> 
> I see we have some flags for broken EEE, but nothing already defined to 
> enable EEE. Seems like this should either be a user option (therefore 
> not in DT) or we should use the broken EEE properties if this is h/w 
> dependent.

In the downstream Raspberry Pi kernel we use DT as a way of passing user settings
to drivers - it's more powerful than the command line. I understand that this is
not the done thing here so I'm withdrawing this element of the patch series.

Apologies for the noise.

>> +- microchip,led-modes: a two-element vector, with each element configuring
>> +  the operating mode of an LED. The values supported by the device are;
>> +  0: Link/Activity
>> +  1: Link1000/Activity
>> +  2: Link100/Activity
>> +  3: Link10/Activity
>> +  4: Link100/1000/Activity
>> +  5: Link10/1000/Activity
>> +  6: Link10/100/Activity
>> +  7: RESERVED
>> +  8: Duplex/Collision
>> +  9: Collision
>> +  10: Activity
>> +  11: RESERVED
>> +  12: Auto-negotiation Fault
>> +  13: RESERVED
>> +  14: Off
>> +  15: On
>> +- microchip,tx-lpi-timer: the delay (in microseconds) between the TX fifo
>> +  becoming empty and invoking Low Power Idles (default 600).
> 
> Needs a unit suffix as defined in property-units.txt.
> 
>> +
>> +Example:
>> +
>> +	/* Standard configuration for a Raspberry Pi 3 B+ */
>> +	ethernet: usbether@1 {
>> +		compatible = "usb424,7800";
>> +		reg = <1>;
>> +		microchip,eee-enabled;
>> +		microchip,tx-lpi-timer = <600>;
>> +		/*
>> +		 * led0 = 1:link1000/activity
>> +		 * led1 = 6:link10/100/activity
>> +		 */
>> +		microchip,led-modes = <1 6>;
>> +	};
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 2328eed..b637aad 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -14482,6 +14482,7 @@ M:	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
>>  L:	netdev@vger.kernel.org
>>  S:	Maintained
>>  F:	drivers/net/usb/lan78xx.*
>> +F:	Documentation/devicetree/bindings/net/microchip,lan78xx.txt
>>  
>>  USB MASS STORAGE DRIVER
>>  M:	Alan Stern <stern@rowland.harvard.edu>
>> -- 
>> 2.7.4
>>