Subject: Re: [PATCH net-next] net: phy: adjust fixed_phy_register() return value

From: Florian Fainelli <[email-masked]>
Date: Wed, 01 Oct 2014 17:33:20 -0700

On 10/01/2014 03:16 PM, Petri Gynther wrote:
> Hi Florian,
> 
> On Wed, Oct 1, 2014 at 2:56 PM, Florian Fainelli <[email-masked]> wrote:
>> On 10/01/2014 02:45 PM, Petri Gynther wrote:
>>> Adjust fixed_phy_register() to return struct phy_device *, so that
>>> it becomes easy to use fixed PHYs without device tree support:
>>>
>>>   phydev = fixed_phy_register(PHY_POLL, &fixed_phy_status, NULL);
>>>   fixed_phy_set_link_update(phydev, fixed_phy_link_update);
>>>   phy_connect_direct(netdev, phydev, handler_fn, phy_interface);
>>>
>>> This change is a prerequisite for modifying bcmgenet driver to work
>>> without a device tree on Broadcom's MIPS-based 7xxx platforms.
>>
>> Without a Device Tree enabled platform, you still have the
>> fixed_phy_add() API to register a fixed PHY at a known location (the
>> second parameter), did we someone broke that with Thomas' patches?
>>
> 
> If a driver uses fixed_phy_add() directly, it then has to call
> get_phy_device() and phy_device_register() as well. But, all that is
> already handled nicely inside fixed_phy_register(). And,
> fixed_phy_register() also handles the fixed PHY address allocation
> automatically.

Sure, the usual model we had before Thomas' patches was to specifically
format phy_id to make sure we would bind to the "fixed-0" MDIO bus
instead of another one, see drivers/net/ethernet/ti/cpmac.c for instance.

> 
> In my opinion, this change makes it really easy to use fixed PHYs from
> non-OF code, as I showed in the change description.

Agreed, and I think it will allow us to get rid of the manual allocation
API eventually.

I let Thomas comment on whether he likes this or not.

> 
> -- Petri
> 
>> You could for instance register a fixed PHY at address 1 for the
>> GENET/MoCA instance to find it.
>>
>> Other than that, I am not opposed to the change, since it allows us to
>> eventually get rid of fixed_phy_add() in the future.
>>
>> Thanks!
>>
>>>
>>> Signed-off-by: Petri Gynther <[email-masked]>
>>> ---
>>>  drivers/net/phy/fixed.c   | 16 ++++++++--------
>>>  drivers/of/of_mdio.c      |  7 +++++--
>>>  include/linux/phy_fixed.h | 14 +++++++-------
>>>  3 files changed, 20 insertions(+), 17 deletions(-)
>>>
>>> diff --git a/drivers/net/phy/fixed.c b/drivers/net/phy/fixed.c
>>> index 5b19fbb..47872caa 100644
>>> --- a/drivers/net/phy/fixed.c
>>> +++ b/drivers/net/phy/fixed.c
>>> @@ -233,9 +233,9 @@ EXPORT_SYMBOL_GPL(fixed_phy_del);
>>>  static int phy_fixed_addr;
>>>  static DEFINE_SPINLOCK(phy_fixed_addr_lock);
>>>
>>> -int fixed_phy_register(unsigned int irq,
>>> -                    struct fixed_phy_status *status,
>>> -                    struct device_node *np)
>>> +struct phy_device *fixed_phy_register(unsigned int irq,
>>> +                                   struct fixed_phy_status *status,
>>> +                                   struct device_node *np)
>>>  {
>>>       struct fixed_mdio_bus *fmb = &platform_fmb;
>>>       struct phy_device *phy;
>>> @@ -246,19 +246,19 @@ int fixed_phy_register(unsigned int irq,
>>>       spin_lock(&phy_fixed_addr_lock);
>>>       if (phy_fixed_addr == PHY_MAX_ADDR) {
>>>               spin_unlock(&phy_fixed_addr_lock);
>>> -             return -ENOSPC;
>>> +             return ERR_PTR(-ENOSPC);
>>>       }
>>>       phy_addr = phy_fixed_addr++;
>>>       spin_unlock(&phy_fixed_addr_lock);
>>>
>>>       ret = fixed_phy_add(PHY_POLL, phy_addr, status);
>>>       if (ret < 0)
>>> -             return ret;
>>> +             return ERR_PTR(ret);
>>>
>>>       phy = get_phy_device(fmb->mii_bus, phy_addr, false);
>>>       if (!phy || IS_ERR(phy)) {
>>>               fixed_phy_del(phy_addr);
>>> -             return -EINVAL;
>>> +             return ERR_PTR(-EINVAL);
>>>       }
>>>
>>>       of_node_get(np);
>>> @@ -269,10 +269,10 @@ int fixed_phy_register(unsigned int irq,
>>>               phy_device_free(phy);
>>>               of_node_put(np);
>>>               fixed_phy_del(phy_addr);
>>> -             return ret;
>>> +             return ERR_PTR(ret);
>>>       }
>>>
>>> -     return 0;
>>> +     return phy;
>>>  }
>>>
>>>  static int __init fixed_mdio_bus_init(void)
>>> diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
>>> index a85d800..907baa9 100644
>>> --- a/drivers/of/of_mdio.c
>>> +++ b/drivers/of/of_mdio.c
>>> @@ -286,6 +286,7 @@ int of_phy_register_fixed_link(struct device_node *np)
>>>       struct device_node *fixed_link_node;
>>>       const __be32 *fixed_link_prop;
>>>       int len;
>>> +     struct phy_device *phy;
>>>
>>>       /* New binding */
>>>       fixed_link_node = of_get_child_by_name(np, "fixed-link");
>>> @@ -299,7 +300,8 @@ int of_phy_register_fixed_link(struct device_node *np)
>>>               status.asym_pause = of_property_read_bool(fixed_link_node,
>>>                                                         "asym-pause");
>>>               of_node_put(fixed_link_node);
>>> -             return fixed_phy_register(PHY_POLL, &status, np);
>>> +             phy = fixed_phy_register(PHY_POLL, &status, np);
>>> +             return (!phy || IS_ERR(phy));
>>>       }
>>>
>>>       /* Old binding */
>>> @@ -310,7 +312,8 @@ int of_phy_register_fixed_link(struct device_node *np)
>>>               status.speed = be32_to_cpu(fixed_link_prop[2]);
>>>               status.pause = be32_to_cpu(fixed_link_prop[3]);
>>>               status.asym_pause = be32_to_cpu(fixed_link_prop[4]);
>>> -             return fixed_phy_register(PHY_POLL, &status, np);
>>> +             phy = fixed_phy_register(PHY_POLL, &status, np);
>>> +             return (!phy || IS_ERR(phy));
>>>       }
>>>
>>>       return -ENODEV;
>>> diff --git a/include/linux/phy_fixed.h b/include/linux/phy_fixed.h
>>> index 9411386..f2ca1b4 100644
>>> --- a/include/linux/phy_fixed.h
>>> +++ b/include/linux/phy_fixed.h
>>> @@ -14,9 +14,9 @@ struct device_node;
>>>  #ifdef CONFIG_FIXED_PHY
>>>  extern int fixed_phy_add(unsigned int irq, int phy_id,
>>>                        struct fixed_phy_status *status);
>>> -extern int fixed_phy_register(unsigned int irq,
>>> -                           struct fixed_phy_status *status,
>>> -                           struct device_node *np);
>>> +extern struct phy_device *fixed_phy_register(unsigned int irq,
>>> +                                          struct fixed_phy_status *status,
>>> +                                          struct device_node *np);
>>>  extern void fixed_phy_del(int phy_addr);
>>>  extern int fixed_phy_set_link_update(struct phy_device *phydev,
>>>                       int (*link_update)(struct net_device *,
>>> @@ -27,11 +27,11 @@ static inline int fixed_phy_add(unsigned int irq, int phy_id,
>>>  {
>>>       return -ENODEV;
>>>  }
>>> -static inline int fixed_phy_register(unsigned int irq,
>>> -                                  struct fixed_phy_status *status,
>>> -                                  struct device_node *np)
>>> +static inline struct phy_device *fixed_phy_register(unsigned int irq,
>>> +                                             struct fixed_phy_status *status,
>>> +                                             struct device_node *np)
>>>  {
>>> -     return -ENODEV;
>>> +     return ERR_PTR(-ENODEV);
>>>  }
>>>  static inline int fixed_phy_del(int phy_addr)
>>>  {
>>>
>>