netdev - Re: [PATCHv3] Fixed PHY: Add fixed_phy_change

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Date:   Fri, 14 Dec 2018 08:05:38 +0000
From:   Joakim Tjernlund <Joakim.Tjernlund@...inera.com>
To:     "claudiu.manoil@....com" <claudiu.manoil@....com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "andrew@...n.ch" <andrew@...n.ch>
Subject: Re: [PATCHv3] Fixed PHY: Add fixed_phy_change_carrier()

On Thu, 2018-12-13 at 10:48 -0800, Florian Fainelli wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
> 
> 
> Le 12/13/18 à 9:47 AM, Joakim Tjernlund a écrit :
> > Drivers can use this as .ndo_change_carrier() to change carrier
> > via /sys/class/net/ethX/carrier.
> > 
> > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@...inera.com>
> 
> Other than a few
> 
> > ---
> > 
> >  v3 - Moved the logic into fixed PHY to minimize eth driver
> >       impact
> > 
> >  v2 - Only allow carrier changes for Fixed PHYs
> > 
> >  I will follow up with drivers using this next.
> 
> You might as well post them as a patch series that way we can review the
> function and its user(s) in one go. Few nitpicks below, but looking good
> otherwise.

OK, will do.

> 
> >  drivers/net/phy/fixed_phy.c | 23 ++++++++++++++++++++++-
> >  include/linux/phy_fixed.h   |  5 +++++
> >  2 files changed, 27 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c
> > index eb5167210681..aedebc251997 100644
> > --- a/drivers/net/phy/fixed_phy.c
> > +++ b/drivers/net/phy/fixed_phy.c
> > @@ -25,6 +25,7 @@
> >  #include <linux/gpio.h>
> >  #include <linux/seqlock.h>
> >  #include <linux/idr.h>
> > +#include <linux/netdevice.h>
> > 
> >  #include "swphy.h"
> > 
> > @@ -38,6 +39,7 @@ struct fixed_phy {
> >       struct phy_device *phydev;
> >       seqcount_t seqcount;
> >       struct fixed_phy_status status;
> > +     bool no_carrier;
> 
> Any reason why this is used with negative logic instead of positive
> logic and calling that just "carrier"?

Yes, both because I like no_carrier better and because 0 as default does not
require explicit initialization. Are you good with that ?

> 
> >       int (*link_update)(struct net_device *, struct fixed_phy_status *);
> >       struct list_head node;
> >       int link_gpio;
> > @@ -48,9 +50,27 @@ static struct fixed_mdio_bus platform_fmb = {
> >       .phys = LIST_HEAD_INIT(platform_fmb.phys),
> >  };
> > 
> > +int
> > +fixed_phy_change_carrier(struct net_device *dev, bool new_carrier)
> 
> Can you put the return type and function name on the same line?

Done.

> 
> > +{
> > +     struct fixed_mdio_bus *fmb = &platform_fmb;
> > +     struct phy_device *phydev = dev->phydev;
> > +     struct fixed_phy *fp;
> > +
> > +     if (!phydev || !phydev->mdio.bus)
> > +             return -EINVAL;
> > +
> > +     list_for_each_entry(fp, &fmb->phys, node) {
> > +             if (fp->addr == phydev->mdio.addr) {
> > +                     fp->no_carrier = !new_carrier;
> > +                     return 0;
> > +             }
> > +     }
> > +     return -EINVAL;
> > +}
> 
> Missing newline and EXPORT_SYMBOL_GPL() here to make that visible to
> modules.

Done.

> 
> >  static void fixed_phy_update(struct fixed_phy *fp)
> >  {
> > -     if (gpio_is_valid(fp->link_gpio))
> > +     if (!fp->no_carrier && gpio_is_valid(fp->link_gpio))
> >               fp->status.link = !!gpio_get_value_cansleep(fp->link_gpio);
> >  }
> > 
> > @@ -66,6 +86,7 @@ static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
> > 
> >                       do {
> >                               s = read_seqcount_begin(&fp->seqcount);
> > +                             fp->status.link = !fp->no_carrier;
> >                               /* Issue callback if user registered it. */
> >                               if (fp->link_update) {
> >                                       fp->link_update(fp->phydev->attached_dev,
> > diff --git a/include/linux/phy_fixed.h b/include/linux/phy_fixed.h
> > index cf6392de6eb0..a711b41f3e20 100644
> > --- a/include/linux/phy_fixed.h
> > +++ b/include/linux/phy_fixed.h
> > @@ -13,6 +13,7 @@ struct fixed_phy_status {
> >  struct device_node;
> > 
> >  #if IS_ENABLED(CONFIG_FIXED_PHY)
> > +extern int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier);
> >  extern int fixed_phy_add(unsigned int irq, int phy_id,
> >                        struct fixed_phy_status *status,
> >                        int link_gpio);
> > @@ -56,6 +57,10 @@ static inline int fixed_phy_update_state(struct phy_device *phydev,
> >  {
> >       return -ENODEV;
> >  }
> > +static inline int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier)
> > +{
> > +     return -EINVAL;
> > +}
> >  #endif /* CONFIG_FIXED_PHY */
> > 
> >  #endif /* __PHY_FIXED_H */
> > 
> 
> --
> Florian