Subject: Re: [PATCH net-next 1/2] dt-bindings: net: dp83822: Add TI dp83822 phy

From: Andrew Lunn <[email-masked]>
Date: Thu, 14 May 2020 20:39:12 +0200

On Thu, May 14, 2020 at 12:30:54PM -0500, Dan Murphy wrote:
> Add a dt binding for the TI dp83822 ethernet phy device.
> 
> CC: Rob Herring <[email-masked]>
> Signed-off-by: Dan Murphy <[email-masked]>
> ---
>  .../devicetree/bindings/net/ti,dp83822.yaml   | 49 +++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/ti,dp83822.yaml
> 
> diff --git a/Documentation/devicetree/bindings/net/ti,dp83822.yaml b/Documentation/devicetree/bindings/net/ti,dp83822.yaml
> new file mode 100644
> index 000000000000..60afd43ad3b6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/ti,dp83822.yaml
> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
> +# Copyright (C) 2020 Texas Instruments Incorporated
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/net/ti,dp83822.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: TI DP83822 ethernet PHY
> +
> +allOf:
> +  - $ref: "ethernet-controller.yaml#"
> +
> +maintainers:
> +  - Dan Murphy <[email-masked]>
> +
> +description: |
> +  The DP83822 is a low-power, single-port, 10/100 Mbps Ethernet PHY. It
> +  provides all of the physical layer functions needed to transmit and receive
> +  data over standard, twisted-pair cables or to connect to an external,
> +  fiber-optic transceiver. Additionally, the DP83822 provides flexibility to
> +  connect to a MAC through a standard MII, RMII, or RGMII interface

Hi Dan

You say 10/100 Mbps Ethernet PHY, but then list RGMII?

> +
> +  Specifications about the charger can be found at:
> +    http://www.ti.com/lit/ds/symlink/dp83822i.pdf
> +
> +properties:
> +  reg:
> +    maxItems: 1
> +
> +  ti,signal-polarity-low:
> +    type: boolean
> +    description: |
> +       DP83822 PHY in Fiber mode only.
> +       Sets the DP83822 to detect a link drop condition when the signal goes
> +       high.  If not set then link drop will occur when the signal goes low.

Are we talking about the LOS line from the SFP cage? In the SFF/SFP
binding we have:

- los-gpios : GPIO phandle and a specifier of the Receiver Loss of Signal
  Indication input gpio signal, active (signal lost) high

It would be nice to have a consistent naming.

Is it required the LOS signal is connected to the PHY? Russell King
has some patches which allows the Marvell PHY to be used as a media
converter. In that setting, i think the SFP signals are connected to
GPIOs not the PHY. The SFP core can then control the transmit disable,
module insertion detection etc. So i'm wondering if you need a
property to indicate the LOS is not connected to the PHY?

	 Andrew