Subject: Re: [PATCHv4 2/5] net: phy: extend fixed driver with fixed_phy_register()

From: Sergei Shtylyov <[email-masked]>
Date: Thu, 3 Sep 2015 22:35:12 +0300

Hello.

On 09/03/2015 10:23 PM, Florian Fainelli wrote:

>>> The existing fixed_phy_add() function has several drawbacks that
>>> prevents it from being used as is for OF-based declaration of fixed
>>> PHYs:
>>>
>>>    * The address of the PHY on the fake bus needs to be passed, while a
>>>      dynamic allocation is desired.
>>>
>>>    * Since the phy_device instantiation is post-poned until the next
>>>      mdiobus scan, there is no way to associate the fixed PHY with its
>>>      OF node, which later prevents of_phy_connect() from finding this
>>>      fixed PHY from a given OF node.
>>>
>>> To solve this, this commit introduces fixed_phy_register(), which will
>>> allocate an available PHY address, add the PHY using fixed_phy_add()
>>> and instantiate the phy_device structure associated with the provided
>>> OF node.
>>>
>>> Signed-off-by: Thomas Petazzoni <[email-masked]>
>>> Acked-by: Florian Fainelli <[email-masked]>
>>> Acked-by: Grant Likely <[email-masked]>
>>> ---
>>>    drivers/net/phy/fixed.c   | 61
>>> +++++++++++++++++++++++++++++++++++++++++++++++
>>>    include/linux/phy_fixed.h | 11 +++++++++
>>>    2 files changed, 72 insertions(+)
>>>
>>> diff --git a/drivers/net/phy/fixed.c b/drivers/net/phy/fixed.c
>>> index e41546d..d60d875 100644
>>> --- a/drivers/net/phy/fixed.c
>>> +++ b/drivers/net/phy/fixed.c
>> [...]
>>> @@ -203,6 +204,66 @@ err_regs:
>> [...]
>>> +int 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;
>>> +    int phy_addr;
>>> +    int ret;
>>> +
>>> +    /* Get the next available PHY address, up to PHY_MAX_ADDR */
>>> +    spin_lock(&phy_fixed_addr_lock);
>>> +    if (phy_fixed_addr == PHY_MAX_ADDR) {
>>> +        spin_unlock(&phy_fixed_addr_lock);
>>> +        return -ENOSPC;
>>> +    }
>>> +    phy_addr = phy_fixed_addr++;
>>> +    spin_unlock(&phy_fixed_addr_lock);
>>> +
>>> +    ret = fixed_phy_add(PHY_POLL, phy_addr, status);
>>
>>     Was rummaging in the fixed_phy driver and a bug sprang right at me:
>> 'phy' should have been passed here, not PHY_POLL. Luckily, all callers
>> pass PHY_POLL anyway...

> Are we looking at the same header file for the prototype of fixed_phy_add()?

    Probably not. I was looking at Linus' tree, yours is probably net-next. :-)

> extern int fixed_phy_add(unsigned int irq, int phy_id,
>                           struct fixed_phy_status *status,
>                           int link_gpio);

> First argument is correct here..

    No, fixed_phy_register() gets 'irq' passed to it and it should in its turn 
call fixed_phy_add() with this argument, not PHY_POLL; otherwise the 'irq' 
parameter gets completely ignored...

> at any rate, if something needs fixing, just go ahead and submit a patch.

    OK.

> --
> Florian

MBR, Sergei