linux-kernel - Re: [PATCH v3 1/2] phy: add new phy_notify

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Message-ID: <CADrjBPpaJdzDSe3kjk=zrODusH3LnwhaBn9-NDCJwEy3ymwvew@mail.gmail.com>
Date: Thu, 11 Sep 2025 13:23:37 +0100
From: Peter Griffin <peter.griffin@...aro.org>
To: Vinod Koul <vkoul@...nel.org>
Cc: Kishon Vijay Abraham I <kishon@...nel.org>, André Draszik <andre.draszik@...aro.org>, 
	Tudor Ambarus <tudor.ambarus@...aro.org>, Alim Akhtar <alim.akhtar@...sung.com>, 
	Krzysztof Kozlowski <krzk@...nel.org>, linux-phy@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-samsung-soc@...r.kernel.org, kernel-team@...roid.com, 
	William Mcvicker <willmcvicker@...gle.com>, Manivannan Sadhasivam <mani@...nel.org>, neil.armstrong@...aro.org
Subject: Re: [PATCH v3 1/2] phy: add new phy_notify_state() api

Hi Vinod,

Thanks for your review feedback.

On Wed, 20 Aug 2025 at 17:34, Vinod Koul <vkoul@...nel.org> wrote:
>
> On 13-08-25, 16:00, Peter Griffin wrote:
> > Add a new phy_notify_state() api that notifies and configures a phy for a
> > given state transition.
> >
> > This is intended to be by phy drivers which need to do some runtime
>                     ^^^^^^^^^^
> Missing 'used' possibly?

Yes your right, good spot, will fix.

>
> > configuration of parameters that can't be handled by phy_calibrate() or
> > phy_power_{on|off}().
> >
> > The first usage of this API is in the Samsung UFS phy that needs to issue
> > some register writes when entering and exiting the hibernate link state.
> >
> > Signed-off-by: Peter Griffin <peter.griffin@...aro.org>
> > ---
> >  drivers/phy/phy-core.c  | 25 +++++++++++++++++++++++++
> >  include/linux/phy/phy.h | 19 +++++++++++++++++++
> >  2 files changed, 44 insertions(+)
> >
> > diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> > index 04a5a34e7a950ae94fae915673c25d476fc071c1..60be8af984bf06649ef00e695d0ed4ced597cdb9 100644
> > --- a/drivers/phy/phy-core.c
> > +++ b/drivers/phy/phy-core.c
> > @@ -520,6 +520,31 @@ int phy_notify_disconnect(struct phy *phy, int port)
> >  }
> >  EXPORT_SYMBOL_GPL(phy_notify_disconnect);
> >
> > +/**
> > + * phy_notify_state() - phy state notification
> > + * @phy: the PHY returned by phy_get()
> > + * @state: the PHY state
> > + *
> > + * Notify the PHY of a state transition. Used to notify and
> > + * configure the PHY accordingly.
> > + *
> > + * Returns: %0 if successful, a negative error code otherwise
> > + */
> > +int phy_notify_state(struct phy *phy, union phy_notify state)
> > +{
> > +     int ret;
> > +
> > +     if (!phy || !phy->ops->notify_phystate)
> > +             return 0;
> > +
> > +     mutex_lock(&phy->mutex);
> > +     ret = phy->ops->notify_phystate(phy, state);
> > +     mutex_unlock(&phy->mutex);
> > +
> > +     return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(phy_notify_state);
> > +
> >  /**
> >   * phy_configure() - Changes the phy parameters
> >   * @phy: the phy returned by phy_get()
> > diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
> > index 13add0c2c40721fe9ca3f0350d13c035cd25af45..664d0864c3a5042949cb121e982368fe0a97827f 100644
> > --- a/include/linux/phy/phy.h
> > +++ b/include/linux/phy/phy.h
> > @@ -53,6 +53,15 @@ enum phy_media {
> >       PHY_MEDIA_DAC,
> >  };
> >
> > +enum phy_ufs_state {
> > +     PHY_UFS_HIBERN8_ENTER,
> > +     PHY_UFS_HIBERN8_EXIT,
> > +};
> > +
> > +union phy_notify {
> > +     enum phy_ufs_state ufs_state;
> > +};
> > +
> >  /**
> >   * union phy_configure_opts - Opaque generic phy configuration
> >   *
> > @@ -83,6 +92,7 @@ union phy_configure_opts {
> >   * @set_speed: set the speed of the phy (optional)
> >   * @reset: resetting the phy
> >   * @calibrate: calibrate the phy
> > + * @notify_phystate: notify and configure the phy for a particular state
> >   * @release: ops to be performed while the consumer relinquishes the PHY
> >   * @owner: the module owner containing the ops
> >   */
> > @@ -132,6 +142,7 @@ struct phy_ops {
> >       int     (*connect)(struct phy *phy, int port);
> >       int     (*disconnect)(struct phy *phy, int port);
> >
> > +     int     (*notify_phystate)(struct phy *phy, union phy_notify state);
> >       void    (*release)(struct phy *phy);
> >       struct module *owner;
> >  };
> > @@ -255,6 +266,7 @@ int phy_reset(struct phy *phy);
> >  int phy_calibrate(struct phy *phy);
> >  int phy_notify_connect(struct phy *phy, int port);
> >  int phy_notify_disconnect(struct phy *phy, int port);
> > +int phy_notify_state(struct phy *phy, union phy_notify state);
> >  static inline int phy_get_bus_width(struct phy *phy)
> >  {
> >       return phy->attrs.bus_width;
> > @@ -412,6 +424,13 @@ static inline int phy_notify_disconnect(struct phy *phy, int index)
> >       return -ENOSYS;
> >  }
> >
> > +static inline int phy_notify_phystate(struct phy *phy, union phy_notify state)
> > +{
> > +     if (!phy)
> > +             return 0;
> > +     return -ENOSYS;
>
> Should be -ENOSYS either way, right?

I initially thought the same, but I followed the pattern that is used
by many of the other phy API calls like phy_init/exit,
phy_power_on/off phy_calibrate, phy_notify_connect in
include/linux/phy/phy.h. I can update it if you like, but I was trying
to keep it consistent.

The only API I can see (that isn't a *phy_get* or *phy_create*) which
returns -ENOSYS unconditionally is phy_get_bus_width()

Thanks,

Peter