[v2,1/3] netdev/of/phy: New function: of_mdio_find_bus().

Add of_mdio_find_bus() which allows an mii_bus to be located given its
associated the device tree node.

This is needed by the follow-on patch to add a driver for MDIO bus
multiplexers.

The of_mdiobus_register() function is modified so that the device tree
node is recorded in the mii_bus.  Then we can find it again by
iterating over all mdio_bus_class devices.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: "David S. Miller" <davem@davemloft.net>
---
 drivers/net/phy/mdio_bus.c |    3 ++-
 drivers/of/of_mdio.c       |   26 ++++++++++++++++++++++++++
 include/linux/of_mdio.h    |    2 ++
 include/linux/phy.h        |    1 +
 4 files changed, 31 insertions(+), 1 deletions(-)

On Tue, Sep 27, 2011 at 04:26:53PM -0700, David Daney wrote:
> Add of_mdio_find_bus() which allows an mii_bus to be located given its
> associated the device tree node.
> 
> This is needed by the follow-on patch to add a driver for MDIO bus
> multiplexers.
> 
> The of_mdiobus_register() function is modified so that the device tree
> node is recorded in the mii_bus.  Then we can find it again by
> iterating over all mdio_bus_class devices.
> 
> Signed-off-by: David Daney <david.daney@cavium.com>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Cc: "David S. Miller" <davem@davemloft.net>
> ---
>  drivers/net/phy/mdio_bus.c |    3 ++-
>  drivers/of/of_mdio.c       |   26 ++++++++++++++++++++++++++
>  include/linux/of_mdio.h    |    2 ++
>  include/linux/phy.h        |    1 +
>  4 files changed, 31 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
> index 6c58da2..227a060 100644
> --- a/drivers/net/phy/mdio_bus.c
> +++ b/drivers/net/phy/mdio_bus.c
> @@ -70,10 +70,11 @@ static void mdiobus_release(struct device *d)
>  	kfree(bus);
>  }
>  
> -static struct class mdio_bus_class = {
> +struct class mdio_bus_class = {
>  	.name		= "mdio_bus",
>  	.dev_release	= mdiobus_release,
>  };
> +EXPORT_SYMBOL(mdio_bus_class);

Instead of exporting this, move the iterator into this file. Assuming
Andy and David are okay with it, I don't see any reason to continue to
keep the MDIO DT support outside of drivers/net/phy.

Bonus points if you craft a patch to move the existing MDIO DT
support code.

Otherwise, the patch looks good.

g.

>  
>  /**
>   * mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
> diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
> index d35e300..7c28e8c 100644
> --- a/drivers/of/of_mdio.c
> +++ b/drivers/of/of_mdio.c
> @@ -45,6 +45,8 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
>  		for (i=0; i<PHY_MAX_ADDR; i++)
>  			mdio->irq[i] = PHY_POLL;
>  
> +	mdio->dev.of_node = np;
> +
>  	/* Register the MDIO bus */
>  	rc = mdiobus_register(mdio);
>  	if (rc)
> @@ -189,3 +191,27 @@ 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);
> +
> +/**
> + * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
> + * @mdio_np: Pointer to the mii_bus.
> + *
> + * Returns a pointer to the mii_bus, or NULL if none found.
> + *
> + * Because the association of a device_node and mii_bus is made via
> + * of_mdiobus_register(), the mii_bus cannot be found before it is
> + * registered with of_mdiobus_register().
> + *
> + */
> +struct mii_bus *of_mdio_find_bus(struct device_node *mdio_np)
> +{
> +	struct device *d;
> +
> +	if (!mdio_np)
> +		return NULL;
> +
> +	d = class_find_device(&mdio_bus_class, NULL,  mdio_np, of_phy_match);
> +
> +	return d ? to_mii_bus(d) : NULL;
> +}
> +EXPORT_SYMBOL(of_mdio_find_bus);
> diff --git a/include/linux/of_mdio.h b/include/linux/of_mdio.h
> index 53b94e0..912c27a 100644
> --- a/include/linux/of_mdio.h
> +++ b/include/linux/of_mdio.h
> @@ -22,4 +22,6 @@ extern struct phy_device *of_phy_connect_fixed_link(struct net_device *dev,
>  					 void (*hndlr)(struct net_device *),
>  					 phy_interface_t iface);
>  
> +extern struct mii_bus *of_mdio_find_bus(struct device_node *mdio_np);
> +
>  #endif /* __LINUX_OF_MDIO_H */
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 54fc413..e4c3844 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -528,4 +528,5 @@ int __init mdio_bus_init(void);
>  void mdio_bus_exit(void);
>  
>  extern struct bus_type mdio_bus_type;
> +extern struct class mdio_bus_class;
>  #endif /* __PHY_H */
> -- 
> 1.7.2.3
> 
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