Re: [RFC PATCH 1/3] of: provide a binding for the 'fixed-link' property

[Florian Fainelli <florian@openwrt.org>]

Hello Thomas,

2013/7/15 Thomas Petazzoni <thomas.petazzoni@free-electrons.com>:
> Some Ethernet MACs have a "fixed link", and are not connected to a
> normal MDIO-managed PHY device. For those situations, a Device Tree
> binding allows to describe a "fixed link", as a "fixed-link" property
> of the Ethernet device Device Tree node.
>
> This patch adds:
>
>  * A documentation for the Device Tree property "fixed-link".
>
>  * A of_phy_register_fixed_link() OF helper, which provided an OF node
>    that contains a "fixed-link" property, registers the corresponding
>    fixed PHY.
>
>  * Removes the warning on the of_phy_connect_fixed_link() that says
>    new drivers should not use it, since Grant Likely indicated that
>    this "fixed-link" property is indeed the way to go.

Some minor nitpicks below. Other than that:

>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: Florian Fainelli <florian@openwrt.org>

> ---
>  .../devicetree/bindings/net/fixed-link.txt         | 26 ++++++++++++++++
>  drivers/of/of_mdio.c                               | 36 +++++++++++++++++++---
>  include/linux/of_mdio.h                            | 10 ++++++
>  3 files changed, 68 insertions(+), 4 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/net/fixed-link.txt
>
> diff --git a/Documentation/devicetree/bindings/net/fixed-link.txt b/Documentation/devicetree/bindings/net/fixed-link.txt
> new file mode 100644
> index 0000000..25a009a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/fixed-link.txt
> @@ -0,0 +1,26 @@
> +Fixed link Device Tree binding
> +------------------------------
> +
> +Some Ethernet MACs have a "fixed link", and are not connected to a
> +normal MDIO-managed PHY device. For those situations, a Device Tree
> +binding allows to describe a "fixed link".

You could also add the following:

"this might be the case when using an Ethernet switch whose management
interface is not accessible using the MDIO bus, or for specific PHYs
where the control path of the PHY might be separated from its data
path".

> +
> +Such a fixed link situation is described within an Ethernet device
> +Device Tree node using a 'fixed-link' property, composed of 5
> +elements:
> +
> + 1. A fake PHY ID, which must be unique accross all fixed-link PHYs in
> +    the system.

You might want to detail that will be used to fake PHY identification
registers 2 & 3.

> + 2. The duplex (1 for full-duplex, 0 for half-duplex)
> + 3. The speed (10, 100, 1000)
> + 4. The pause setting (1 for enabled, 0 for disabled)
> + 5. The asym pause setting (1 for enabled, 0 for disabled)
> +
> +Example:
> +
> +ethernet@0 {
> +       ...
> +       fixed-link = <1 1 1000 0 0>;
> +       ...
> +};
> +
> diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
> index d5a57a9..66d5591 100644
> --- a/drivers/of/of_mdio.c
> +++ b/drivers/of/of_mdio.c
> @@ -14,6 +14,7 @@
>  #include <linux/netdevice.h>
>  #include <linux/err.h>
>  #include <linux/phy.h>
> +#include <linux/phy_fixed.h>
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_mdio.h>
> @@ -215,10 +216,6 @@ EXPORT_SYMBOL(of_phy_connect);
>   * @dev: pointer to net_device claiming the phy
>   * @hndlr: Link state callback for the network device
>   * @iface: PHY data interface type
> - *
> - * This function is a temporary stop-gap and will be removed soon.  It is
> - * only to support the fs_enet, ucc_geth and gianfar Ethernet drivers.  Do
> - * not call this function from new drivers.
>   */
>  struct phy_device *of_phy_connect_fixed_link(struct net_device *dev,
>                                              void (*hndlr)(struct net_device *),
> @@ -247,3 +244,34 @@ struct phy_device *of_phy_connect_fixed_link(struct net_device *dev,
>         return IS_ERR(phy) ? NULL : phy;
>  }
>  EXPORT_SYMBOL(of_phy_connect_fixed_link);
> +
> +#if defined(CONFIG_FIXED_PHY)
> +/**
> + * of_phy_register_fixed_link - Parse fixed-link property and register a dummy phy
> + * @np: pointer to the OF device node that contains the "fixed-link"
> + * property for which a dummy phy should be registered.
> + */
> +#define FIXED_LINK_PROPERTIES_COUNT 5
> +int of_phy_register_fixed_link(struct device_node *np)
> +{
> +       struct fixed_phy_status status = {};
> +       u32 fixed_link_props[FIXED_LINK_PROPERTIES_COUNT];
> +       int ret;
> +
> +       ret = of_property_read_u32_array(np, "fixed-link",
> +                                        fixed_link_props,
> +                                        FIXED_LINK_PROPERTIES_COUNT);
> +       if (ret < 0)
> +               return ret;
> +
> +       status.link       = 1;
> +       status.duplex     = fixed_link_props[1];
> +       status.speed      = fixed_link_props[2];
> +       status.pause      = fixed_link_props[3];
> +       status.asym_pause = fixed_link_props[4];
> +
> +       return fixed_phy_add(PHY_POLL, fixed_link_props[0],
> +                            &status);
> +}
> +EXPORT_SYMBOL(of_phy_register_fixed_link);
> +#endif
> diff --git a/include/linux/of_mdio.h b/include/linux/of_mdio.h
> index 8163107..bf6efea 100644
> --- a/include/linux/of_mdio.h
> +++ b/include/linux/of_mdio.h
> @@ -57,4 +57,14 @@ static inline struct mii_bus *of_mdio_find_bus(struct device_node *mdio_np)
>  }
>  #endif /* CONFIG_OF */
>
> +#if defined(CONFIG_OF) && defined(CONFIG_FIXED_PHY)
> +extern int of_phy_register_fixed_link(struct device_node *np);
> +#else
> +static inline int of_phy_register_fixed_link(struct device_node *np)
> +{
> +       return -ENOSYS;
> +}
> +#endif
> +
> +
>  #endif /* __LINUX_OF_MDIO_H */
> --
> 1.8.1.2
>



--
Florian