Re: [net-next: PATCH v4 1/7] device property: Introduce fwnode_get_mac_address()

[Rafael J. Wysocki]

On Thu, Jan 18, 2018 at 1:31 PM, Marcin Wojtas <mw@xxxxxxxxxxxx> wrote:
> Until now there were two almost identical functions for
> obtaining MAC address - of_get_mac_address() and, more generic,
> device_get_mac_address(). However it is not uncommon,
> that the network interface is represented as a child
> of the actual controller, hence it is not associated
> directly to any struct device, required by the latter
> routine.
>
> This commit allows for getting the MAC address for
> children nodes in the ACPI world by introducing a new function -
> fwnode_get_mac_address(). This commit also changes
> device_get_mac_address() routine to be its wrapper, in order
> to prevent unnecessary duplication.
>
> Signed-off-by: Marcin Wojtas <mw@xxxxxxxxxxxx>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
>  drivers/base/property.c  | 28 ++++++++++++++------
>  include/linux/property.h |  2 ++
>  2 files changed, 22 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index 851b1b6..f261d1a 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -1153,11 +1153,11 @@ int device_get_phy_mode(struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(device_get_phy_mode);
>
> -static void *device_get_mac_addr(struct device *dev,
> +static void *fwnode_get_mac_addr(struct fwnode_handle *fwnode,
>                                  const char *name, char *addr,
>                                  int alen)
>  {
> -       int ret = device_property_read_u8_array(dev, name, addr, alen);
> +       int ret = fwnode_property_read_u8_array(fwnode, name, addr, alen);
>
>         if (ret == 0 && alen == ETH_ALEN && is_valid_ether_addr(addr))
>                 return addr;
> @@ -1165,8 +1165,8 @@ static void *device_get_mac_addr(struct device *dev,
>  }
>
>  /**
> - * device_get_mac_address - Get the MAC for a given device
> - * @dev:       Pointer to the device
> + * fwnode_get_mac_address - Get the MAC from the firmware node
> + * @fwnode:    Pointer to the firmware node
>   * @addr:      Address of buffer to store the MAC in
>   * @alen:      Length of the buffer pointed to by addr, should be ETH_ALEN
>   *
> @@ -1187,19 +1187,31 @@ static void *device_get_mac_addr(struct device *dev,
>   * In this case, the real MAC is in 'local-mac-address', and 'mac-address'
>   * exists but is all zeros.
>  */
> -void *device_get_mac_address(struct device *dev, char *addr, int alen)
> +void *fwnode_get_mac_address(struct fwnode_handle *fwnode, char *addr, int alen)
>  {
>         char *res;
>
> -       res = device_get_mac_addr(dev, "mac-address", addr, alen);
> +       res = fwnode_get_mac_addr(fwnode, "mac-address", addr, alen);
>         if (res)
>                 return res;
>
> -       res = device_get_mac_addr(dev, "local-mac-address", addr, alen);
> +       res = fwnode_get_mac_addr(fwnode, "local-mac-address", addr, alen);
>         if (res)
>                 return res;
>
> -       return device_get_mac_addr(dev, "address", addr, alen);
> +       return fwnode_get_mac_addr(fwnode, "address", addr, alen);
> +}
> +EXPORT_SYMBOL(fwnode_get_mac_address);

That should be EXPORT_SYMBOL_GPL().

I have overlooked that previously, sorry about that.

> +
> +/**
> + * device_get_mac_address - Get the MAC for a given device
> + * @dev:       Pointer to the device
> + * @addr:      Address of buffer to store the MAC in
> + * @alen:      Length of the buffer pointed to by addr, should be ETH_ALEN
> + */
> +void *device_get_mac_address(struct device *dev, char *addr, int alen)
> +{
> +       return fwnode_get_mac_address(dev_fwnode(dev), addr, alen);
>  }
>  EXPORT_SYMBOL(device_get_mac_address);

Same here.

Generally speaking, you should use EXPORT_SYMBOL_GPL() everywhere
unless there's a specific reason for not doing that in which cases
that specific reason has to be clearly spelled out at least in the
changelog of the patch, but really better in a code comment.

>
> diff --git a/include/linux/property.h b/include/linux/property.h
> index f6189a3..35620e0 100644
> --- a/include/linux/property.h
> +++ b/include/linux/property.h
> @@ -279,6 +279,8 @@ int device_get_phy_mode(struct device *dev);
>
>  void *device_get_mac_address(struct device *dev, char *addr, int alen);
>
> +void *fwnode_get_mac_address(struct fwnode_handle *fwnode,
> +                            char *addr, int alen);
>  struct fwnode_handle *fwnode_graph_get_next_endpoint(
>         const struct fwnode_handle *fwnode, struct fwnode_handle *prev);
>  struct fwnode_handle *
> --