Re: [net-next PATCH v7 02/16] net: phy: Introduce fwnode_mdio_find_device()

[Saravana Kannan]

On Wed, Mar 10, 2021 at 10:21 PM Calvin Johnson
<calvin.johnson@xxxxxxxxxxx> wrote:
>
> Define fwnode_mdio_find_device() to get a pointer to the
> mdio_device from fwnode passed to the function.
>
> Refactor of_mdio_find_device() to use fwnode_mdio_find_device().
>
> Signed-off-by: Calvin Johnson <calvin.johnson@xxxxxxxxxxx>
> ---
>
> Changes in v7:
> - correct fwnode_mdio_find_device() description
>
> Changes in v6:
> - fix warning for function parameter of fwnode_mdio_find_device()
>
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
>
>  drivers/net/mdio/of_mdio.c   | 11 +----------
>  drivers/net/phy/phy_device.c | 23 +++++++++++++++++++++++
>  include/linux/phy.h          |  6 ++++++
>  3 files changed, 30 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/mdio/of_mdio.c b/drivers/net/mdio/of_mdio.c
> index ea9d5855fb52..d5e0970b2561 100644
> --- a/drivers/net/mdio/of_mdio.c
> +++ b/drivers/net/mdio/of_mdio.c
> @@ -347,16 +347,7 @@ EXPORT_SYMBOL(of_mdiobus_register);
>   */
>  struct mdio_device *of_mdio_find_device(struct device_node *np)
>  {
> -       struct device *d;
> -
> -       if (!np)
> -               return NULL;
> -
> -       d = bus_find_device_by_of_node(&mdio_bus_type, np);
> -       if (!d)
> -               return NULL;
> -
> -       return to_mdio_device(d);
> +       return fwnode_mdio_find_device(of_fwnode_handle(np));
>  }
>  EXPORT_SYMBOL(of_mdio_find_device);
>
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index cc38e326405a..daabb17bba00 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -2819,6 +2819,29 @@ static bool phy_drv_supports_irq(struct phy_driver *phydrv)
>         return phydrv->config_intr && phydrv->handle_interrupt;
>  }
>
> +/**
> + * fwnode_mdio_find_device - Given a fwnode, find the mdio_device
> + * @fwnode: pointer to the mdio_device's fwnode
> + *
> + * If successful, returns a pointer to the mdio_device with the embedded
> + * struct device refcount incremented by one, or NULL on failure.
> + * The caller should call put_device() on the mdio_device after its use.
> + */
> +struct mdio_device *fwnode_mdio_find_device(struct fwnode_handle *fwnode)
> +{
> +       struct device *d;
> +
> +       if (!fwnode)
> +               return NULL;
> +
> +       d = bus_find_device_by_fwnode(&mdio_bus_type, fwnode);

Sorry about the late review, but can you look into using
get_dev_from_fwnode()? As long as you aren't registering two devices
for the same fwnode, it's an O(1) operation instead of having to loop
through a list of devices in a bus. You can check the returned
device's bus type if you aren't sure about not registering two devices
with the same fw_node and then fall back to this looping.

-Saravana

> +       if (!d)
> +               return NULL;
> +
> +       return to_mdio_device(d);
> +}
> +EXPORT_SYMBOL(fwnode_mdio_find_device);
> +
>  /**
>   * phy_probe - probe and init a PHY device
>   * @dev: device to probe and init
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 1a12e4436b5b..f5eb1e3981a1 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -1366,11 +1366,17 @@ struct phy_device *phy_device_create(struct mii_bus *bus, int addr, u32 phy_id,
>                                      bool is_c45,
>                                      struct phy_c45_device_ids *c45_ids);
>  #if IS_ENABLED(CONFIG_PHYLIB)
> +struct mdio_device *fwnode_mdio_find_device(struct fwnode_handle *fwnode);
>  struct phy_device *get_phy_device(struct mii_bus *bus, int addr, bool is_c45);
>  int phy_device_register(struct phy_device *phy);
>  void phy_device_free(struct phy_device *phydev);
>  #else
>  static inline
> +struct mdio_device *fwnode_mdio_find_device(struct fwnode_handle *fwnode)
> +{
> +       return 0;
> +}
> +static inline
>  struct phy_device *get_phy_device(struct mii_bus *bus, int addr, bool is_c45)
>  {
>         return NULL;
> --
> 2.17.1
>