[1/3] net: phy: add minimal support for QSGMII PHY

This commit adds the necessary definitions for the PHY layer to
recognize "qsgmii" as a valid PHY interface. A QSMII interface, as
defined at
http://en.wikipedia.org/wiki/Media_Independent_Interface#Quad_Serial_Gigabit_Media_Independent_Interface,
is "is a method of combining four SGMII lines into a 5Gbit/s
interface. QSGMII, like SGMII, uses LVDS signalling for the TX and RX
data and a single LVDS clock signal. QSGMII uses significantly fewer
signal lines than four SGMII busses."

This type of MAC <-> PHY connection might require special handling on
the MAC driver side, so it should be possible to express this type of
MAC <-> PHY connection, for example in the Device Tree.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: devicetree@vger.kernel.org
---
 Documentation/devicetree/bindings/net/ethernet.txt | 2 +-
 include/linux/phy.h                                | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

2014-04-15 6:50 GMT-07:00 Thomas Petazzoni
<thomas.petazzoni@free-electrons.com>:
> This commit adds the necessary definitions for the PHY layer to
> recognize "qsgmii" as a valid PHY interface. A QSMII interface, as
> defined at
> http://en.wikipedia.org/wiki/Media_Independent_Interface#Quad_Serial_Gigabit_Media_Independent_Interface,
> is "is a method of combining four SGMII lines into a 5Gbit/s
> interface. QSGMII, like SGMII, uses LVDS signalling for the TX and RX
> data and a single LVDS clock signal. QSGMII uses significantly fewer
> signal lines than four SGMII busses."
>
> This type of MAC <-> PHY connection might require special handling on
> the MAC driver side, so it should be possible to express this type of
> MAC <-> PHY connection, for example in the Device Tree.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

> Cc: devicetree@vger.kernel.org
> ---
>  Documentation/devicetree/bindings/net/ethernet.txt | 2 +-
>  include/linux/phy.h                                | 3 +++
>  2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/net/ethernet.txt b/Documentation/devicetree/bindings/net/ethernet.txt
> index 9ecd43d..3fc3605 100644
> --- a/Documentation/devicetree/bindings/net/ethernet.txt
> +++ b/Documentation/devicetree/bindings/net/ethernet.txt
> @@ -10,7 +10,7 @@ The following properties are common to the Ethernet controllers:
>  - max-frame-size: number, maximum transfer unit (IEEE defined MTU), rather than
>    the maximum frame size (there's contradiction in ePAPR).
>  - phy-mode: string, operation mode of the PHY interface; supported values are
> -  "mii", "gmii", "sgmii", "tbi", "rev-mii", "rmii", "rgmii", "rgmii-id",
> +  "mii", "gmii", "sgmii", "qsgmii", "tbi", "rev-mii", "rmii", "rgmii", "rgmii-id",
>    "rgmii-rxid", "rgmii-txid", "rtbi", "smii", "xgmii"; this is now a de-facto
>    standard property;
>  - phy-connection-type: the same as "phy-mode" property but described in ePAPR;
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 24126c4..4d0221f 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -75,6 +75,7 @@ typedef enum {
>         PHY_INTERFACE_MODE_SMII,
>         PHY_INTERFACE_MODE_XGMII,
>         PHY_INTERFACE_MODE_MOCA,
> +       PHY_INTERFACE_MODE_QSGMII,
>         PHY_INTERFACE_MODE_MAX,
>  } phy_interface_t;
>
> @@ -116,6 +117,8 @@ static inline const char *phy_modes(phy_interface_t interface)
>                 return "xgmii";
>         case PHY_INTERFACE_MODE_MOCA:
>                 return "moca";
> +       case PHY_INTERFACE_MODE_QSGMII:
> +               return "qsgmii";
>         default:
>                 return "unknown";
>         }
> --
> 1.8.3.2
>
>
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