Subject: Re: [net-next PATCH v2 1/3] device property: Introduce phy related fwnode functions

From: Russell King - ARM Linux admin <[email-masked]>
Date: Mon, 27 Apr 2020 14:36:55 +0100

On Mon, Apr 27, 2020 at 06:54:07PM +0530, Calvin Johnson wrote:
> Define fwnode_phy_find_device() to iterate an mdiobus and find the
> phy device of the provided phy fwnode. Additionally define
> device_phy_find_device() to find phy device of provided device.
> 
> Define fwnode_get_phy_node() to get phy_node using named reference.
> 
> Signed-off-by: Calvin Johnson <[email-masked]>
> ---
> 
> Changes in v2:
>   move phy code from base/property.c to net/phy/phy_device.c
>   replace acpi & of code to get phy-handle with fwnode_find_reference
> 
>  drivers/net/phy/phy_device.c | 55 ++++++++++++++++++++++++++++++++++++
>  include/linux/phy.h          |  3 ++
>  2 files changed, 58 insertions(+)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 7e1ddd5745d2..a2f3dbba8a3c 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -31,6 +31,7 @@
>  #include <linux/mdio.h>
>  #include <linux/io.h>
>  #include <linux/uaccess.h>
> +#include <linux/property.h>
>  
>  MODULE_DESCRIPTION("PHY library");
>  MODULE_AUTHOR("Andy Fleming");
> @@ -2436,6 +2437,60 @@ static bool phy_drv_supports_irq(struct phy_driver *phydrv)
>  	return phydrv->config_intr && phydrv->ack_interrupt;
>  }
>  
> +/**
> + * fwnode_phy_find_device - Find phy_device on the mdiobus for the provided
> + * phy_fwnode.
> + * @phy_fwnode: Pointer to the phy's fwnode.
> + *
> + * If successful, returns a pointer to the phy_device with the embedded
> + * struct device refcount incremented by one, or NULL on failure.
> + */
> +struct phy_device *fwnode_phy_find_device(struct fwnode_handle *phy_fwnode)
> +{
> +	struct device *d;
> +	struct mdio_device *mdiodev;
> +
> +	if (!phy_fwnode)
> +		return NULL;
> +
> +	d = bus_find_device_by_fwnode(&mdio_bus_type, phy_fwnode);
> +	if (d) {
> +		mdiodev = to_mdio_device(d);
> +		if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY)
> +			return to_phy_device(d);
> +		put_device(d);
> +	}
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL(fwnode_phy_find_device);
> +
> +/**
> + * device_phy_find_device - For the given device, get the phy_device
> + * @dev: Pointer to the given device
> + *
> + * If successful, returns a pointer to the phy_device with the embedded
> + * struct device refcount incremented by one, or NULL on failure.
> + */
> +struct phy_device *device_phy_find_device(struct device *dev)
> +{
> +	return fwnode_phy_find_device(dev_fwnode(dev));
> +}
> +EXPORT_SYMBOL_GPL(device_phy_find_device);
> +
> +/**
> + * fwnode_get_phy_node - Get the phy_node using the named reference.
> + * @fwnode: Pointer to fwnode from which phy_node has to be obtained.
> + *
> + * Returns pointer to the phy fwnode, or ERR_PTR. Caller is responsible to
> + * call fwnode_handle_put() on the returned phy fwnode pointer.
> + */
> +struct fwnode_handle *fwnode_get_phy_node(struct fwnode_handle *fwnode)
> +{
> +	return fwnode_find_reference(fwnode, "phy-handle", 0);
> +}
> +EXPORT_SYMBOL_GPL(fwnode_get_phy_node);
> +
>  /**
>   * 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 e2bfb9240587..f0450ef2dc9b 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -1328,6 +1328,9 @@ void phy_set_asym_pause(struct phy_device *phydev, bool rx, bool tx);
>  bool phy_validate_pause(struct phy_device *phydev,
>  			struct ethtool_pauseparam *pp);
>  void phy_get_pause(struct phy_device *phydev, bool *tx_pause, bool *rx_pause);
> +struct phy_device *fwnode_phy_find_device(struct fwnode_handle *phy_fwnode);
> +struct phy_device *device_phy_find_device(struct device *dev);
> +struct fwnode_handle *fwnode_get_phy_node(struct fwnode_handle *fwnode);
>  void phy_resolve_pause(unsigned long *local_adv, unsigned long *partner_adv,
>  		       bool *tx_pause, bool *rx_pause);
>  

I think you can find a better location in this file to places these
function prototypes - putting them in the middle of a set of prototypes
for pause-related functions looks like you printed the file out, and
played "pin the tail on the donkey" to select somewhere to put them!

I think putting them near the get_phy_device() prototype would be
sensible.  Also, consider the case where CONFIG_PHYLIB is not set.
Do we need stub implementations of these functions to avoid ifdefs
in C code?

Thanks.

-- 
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