Re: [PATCH v6 2/2] phy: rockchip-inno-usb2: add a new driver for Rockchip usb2phy

[Frank Wang]

Hi Guenter,

On 2016/6/17 21:20, Guenter Roeck wrote:
> Hi Frank,
>
> On 06/16/2016 11:43 PM, Frank Wang wrote:
> > Hi Guenter,
> >
> > On 2016/6/17 12:59, Guenter Roeck wrote:
> > > On 06/16/2016 07:09 PM, Frank Wang wrote:
> > > > The newer SoCs (rk3366, rk3399) take a different usb-phy IP block
> > > > than rk3288 and before, and most of phy-related registers are also
> > > > different from the past, so a new phy driver is required necessarily.
> > > >
> > > > Signed-off-by: Frank Wang <frank.wang@xxxxxxxxxxxxxx>
> > > > Suggested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > > > Suggested-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> > > > Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
> > > > Tested-by: Heiko Stuebner <heiko@xxxxxxxxx>
> > > > ---
> > >
> > > [ ... ]
> > >
> > > > +
> > > > +static int rockchip_usb2phy_resume(struct phy *phy)
> > > > +{
> > > > +    struct rockchip_usb2phy_port *rport = phy_get_drvdata(phy);
> > > > +    struct rockchip_usb2phy *rphy = dev_get_drvdata(phy->dev.parent);
> > > > +    int ret;
> > > > +
> > > > +    dev_dbg(&rport->phy->dev, "port resume\n");
> > > > +
> > > > +    ret = clk_prepare_enable(rphy->clk480m);
> > > > +    if (ret)
> > > > +        return ret;
> > > > +
> > > If suspend can be called multiple times, resume can be called
> > > multiple times as well. Doesn't this cause a clock imbalance
> > > if you call clk_prepare_enable() multiple times on resume,
> > > but clk_disable_unprepare() only once on suspend ?
> >
> > Well, what you said is reasonable, How does something like below?
> >
> > @@ -307,6 +307,9 @@ static int rockchip_usb2phy_resume(struct phy *phy)
> >
> >          dev_dbg(&rport->phy->dev, "port resume\n");
> >
> > +       if (!rport->suspended)
> > +               return 0;
> > +
> >          ret = clk_prepare_enable(rphy->clk480m);
> >          if (ret)
> >                  return ret;
> > @@ -327,12 +330,16 @@ static int rockchip_usb2phy_suspend(struct phy 
> > *phy)
> >
> >          dev_dbg(&rport->phy->dev, "port suspend\n");
> >
> > +       if (rport->suspended)
> > +               return 0;
> > +
> >          ret = property_enable(rphy, &rport->port_cfg->phy_sus, true);
> >          if (ret)
> >                  return ret;
> >
> >          rport->suspended = true;
> >          clk_disable_unprepare(rphy->clk480m);
> > +
> >          return 0;
> >   }
> >
> > @@ -485,6 +492,7 @@ static int rockchip_usb2phy_host_port_init(struct 
> > rockchip_usb2phy *rphy,
> >
> >          rport->port_id = USB2PHY_PORT_HOST;
> >          rport->port_cfg = &rphy->phy_cfg->port_cfgs[USB2PHY_PORT_HOST];
> > +       rport->suspended = true;
>
> Why does it start in suspended mode ? That seems odd.

This is an initialization. Using above design which make 'suspended' as 
a condition both in *_usb2phy_resume and *_usb2phy_suspend, I believe if 
it is not initialized as suspended mode, the first resume process will 
be skipped. Theoretically, the phy-port in suspended mode make sense 
when it is at start time, then the upper layer controller will invoke 
phy_power_on (See phy-core.c), and it further call back *_usb2phy_resume 
to make phy-port work properly.

So could you tell me what make you feeling odd or would you like to give 
another appropriate way please? :-)

BR.
Frank

> >          mutex_init(&rport->mutex);
> >          INIT_DELAYED_WORK(&rport->sm_work, rockchip_usb2phy_sm_work);