diff mbox series

[V3,net-next,3/4] net: phy: realtek: add dt property to enable ALDPS mode

Message ID 20210608031535.3651-4-qiangqing.zhang@nxp.com
State Superseded
Headers show
Series net: phy: add dt property for realtek phy | expand

Commit Message

Joakim Zhang June 8, 2021, 3:15 a.m. UTC 
If enable Advance Link Down Power Saving (ALDPS) mode, it will change
crystal/clock behavior, which cause RXC clock stop for dozens to hundreds
of miliseconds. This is comfirmed by Realtek engineer. For some MACs, it
needs RXC clock to support RX logic, after this patch, PHY can generate
continuous RXC clock during auto-negotiation.

ALDPS default is disabled after hardware reset, it's more reasonable to
add a property to enable this feature, since ALDPS would introduce side effect.
This patch adds dt property "realtek,aldps-enable" to enable ALDPS mode
per users' requirement.

Jisheng Zhang enables this feature, changes the default behavior. Since
mine patch breaks the rule that new implementation should not break
existing design, so Cc'ed let him know to see if it can be accepted.

Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
---
 drivers/net/phy/realtek.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

Comments

Jisheng Zhang June 8, 2021, 9:51 a.m. UTC | #1 
On Tue,  8 Jun 2021 11:15:34 +0800
Joakim Zhang <qiangqing.zhang@nxp.com> wrote:


> 
> 
> If enable Advance Link Down Power Saving (ALDPS) mode, it will change
> crystal/clock behavior, which cause RXC clock stop for dozens to hundreds
> of miliseconds. This is comfirmed by Realtek engineer. For some MACs, it
> needs RXC clock to support RX logic, after this patch, PHY can generate
> continuous RXC clock during auto-negotiation.
> 
> ALDPS default is disabled after hardware reset, it's more reasonable to
> add a property to enable this feature, since ALDPS would introduce side effect.
> This patch adds dt property "realtek,aldps-enable" to enable ALDPS mode
> per users' requirement.
> 
> Jisheng Zhang enables this feature, changes the default behavior. Since
> mine patch breaks the rule that new implementation should not break
> existing design, so Cc'ed let him know to see if it can be accepted.
> 
> Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> ---
>  drivers/net/phy/realtek.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> index ca258f2a9613..79dc55bb4091 100644
> --- a/drivers/net/phy/realtek.c
> +++ b/drivers/net/phy/realtek.c
> @@ -76,6 +76,7 @@ MODULE_AUTHOR("Johnson Leung");
>  MODULE_LICENSE("GPL");
> 
>  struct rtl821x_priv {
> +       u16 phycr1;
>         u16 phycr2;
>  };
> 
> @@ -98,6 +99,14 @@ static int rtl821x_probe(struct phy_device *phydev)
>         if (!priv)
>                 return -ENOMEM;
> 
> +       priv->phycr1 = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR1);
> +       if (priv->phycr1 < 0)
> +               return priv->phycr1;
> +
> +       priv->phycr1 &= (RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF);

priv->phycr1 is 0 by default, so above 5 LoCs can be removed

> +       if (of_property_read_bool(dev->of_node, "realtek,aldps-enable"))
> +               priv->phycr1 |= RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF;
> +
>         priv->phycr2 = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR2);
>         if (priv->phycr2 < 0)
>                 return priv->phycr2;
> @@ -324,11 +333,16 @@ static int rtl8211f_config_init(struct phy_device *phydev)
>         struct rtl821x_priv *priv = phydev->priv;
>         struct device *dev = &phydev->mdio.dev;
>         u16 val_txdly, val_rxdly;
> -       u16 val;
>         int ret;
> 
> -       val = RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_XTAL_OFF;
> -       phy_modify_paged_changed(phydev, 0xa43, RTL8211F_PHYCR1, val, val);
> +       ret = phy_modify_paged_changed(phydev, 0xa43, RTL8211F_PHYCR1,
> +                                      RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF,
> +                                      priv->phycr1);
> +       if (ret < 0) {
> +               dev_err(dev, "aldps mode  configuration failed: %pe\n",
> +                       ERR_PTR(ret));
> +               return ret;
> +       }
> 
>         switch (phydev->interface) {
>         case PHY_INTERFACE_MODE_RGMII:
> --
> 2.17.1
>
Jisheng Zhang June 9, 2021, 1:56 a.m. UTC | #2 
On Tue, 8 Jun 2021 10:14:40 +0000
Joakim Zhang <qiangqing.zhang@nxp.com> wrote:


> 

> 

> Hi Jisheng,


Hi,

> 

> > -----Original Message-----

> > From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> > Sent: 2021年6月8日 17:51

> > To: Joakim Zhang <qiangqing.zhang@nxp.com>

> > Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;

> > andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;

> > f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;

> > netdev@vger.kernel.org; devicetree@vger.kernel.org;

> > linux-kernel@vger.kernel.org

> > Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt property to

> > enable ALDPS mode

> >

> > On Tue,  8 Jun 2021 11:15:34 +0800

> > Joakim Zhang <qiangqing.zhang@nxp.com> wrote:

> >

> >  

> > >

> > >

> > > If enable Advance Link Down Power Saving (ALDPS) mode, it will change

> > > crystal/clock behavior, which cause RXC clock stop for dozens to

> > > hundreds of miliseconds. This is comfirmed by Realtek engineer. For

> > > some MACs, it needs RXC clock to support RX logic, after this patch,

> > > PHY can generate continuous RXC clock during auto-negotiation.

> > >

> > > ALDPS default is disabled after hardware reset, it's more reasonable

> > > to add a property to enable this feature, since ALDPS would introduce side  

> > effect.  

> > > This patch adds dt property "realtek,aldps-enable" to enable ALDPS

> > > mode per users' requirement.

> > >

> > > Jisheng Zhang enables this feature, changes the default behavior.

> > > Since mine patch breaks the rule that new implementation should not

> > > break existing design, so Cc'ed let him know to see if it can be accepted.

> > >

> > > Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> > > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>

> > > ---

> > >  drivers/net/phy/realtek.c | 20 +++++++++++++++++---

> > >  1 file changed, 17 insertions(+), 3 deletions(-)

> > >

> > > diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c

> > > index ca258f2a9613..79dc55bb4091 100644

> > > --- a/drivers/net/phy/realtek.c

> > > +++ b/drivers/net/phy/realtek.c

> > > @@ -76,6 +76,7 @@ MODULE_AUTHOR("Johnson Leung");

> > > MODULE_LICENSE("GPL");

> > >

> > >  struct rtl821x_priv {

> > > +       u16 phycr1;

> > >         u16 phycr2;

> > >  };

> > >

> > > @@ -98,6 +99,14 @@ static int rtl821x_probe(struct phy_device *phydev)

> > >         if (!priv)

> > >                 return -ENOMEM;

> > >

> > > +       priv->phycr1 = phy_read_paged(phydev, 0xa43,  

> > RTL8211F_PHYCR1);  

> > > +       if (priv->phycr1 < 0)

> > > +               return priv->phycr1;

> > > +

> > > +       priv->phycr1 &= (RTL8211F_ALDPS_PLL_OFF |

> > > + RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF); 


I believe your intention is

priv->phycr1 &= ~(RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF); 
However, this is not necessary. See below.

> >

> > priv->phycr1 is 0 by default, so above 5 LoCs can be removed  

> 

> The intention of this is to take bootloader into account. Such as uboot configure the PHY before.


The last param "set" of phy_modify_paged_changed() means *bit mask of bits to set*
If we don't want to enable ALDPS, 0 is enough.

Even if uboot configured the PHY before linux, I believe phy_modify_paged_changed()
can clear ALDPS bits w/o above 5 LoCs. 

Thanks

> 

> Best Regards,

> Joakim Zhang

> > > +       if (of_property_read_bool(dev->of_node, "realtek,aldps-enable"))

> > > +               priv->phycr1 |= RTL8211F_ALDPS_PLL_OFF |

> > > + RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF;

> > > +

> > >         priv->phycr2 = phy_read_paged(phydev, 0xa43,  

> > RTL8211F_PHYCR2);  

> > >         if (priv->phycr2 < 0)

> > >                 return priv->phycr2;

> > > @@ -324,11 +333,16 @@ static int rtl8211f_config_init(struct phy_device  

> > *phydev)  

> > >         struct rtl821x_priv *priv = phydev->priv;

> > >         struct device *dev = &phydev->mdio.dev;

> > >         u16 val_txdly, val_rxdly;

> > > -       u16 val;

> > >         int ret;

> > >

> > > -       val = RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_PLL_OFF |  

> > RTL8211F_ALDPS_XTAL_OFF;  

> > > -       phy_modify_paged_changed(phydev, 0xa43, RTL8211F_PHYCR1, val,  

> > val);  

> > > +       ret = phy_modify_paged_changed(phydev, 0xa43,  

> > RTL8211F_PHYCR1,  

> > > +                                      RTL8211F_ALDPS_PLL_OFF |  

> > RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF,  

> > > +                                      priv->phycr1);

> > > +       if (ret < 0) {

> > > +               dev_err(dev, "aldps mode  configuration failed: %pe\n",

> > > +                       ERR_PTR(ret));

> > > +               return ret;

> > > +       }

> > >

> > >         switch (phydev->interface) {

> > >         case PHY_INTERFACE_MODE_RGMII:

> > > --

> > > 2.17.1

> > >  

>
Joakim Zhang June 9, 2021, 2:51 a.m. UTC | #3 
Hi Jisheng,

> -----Original Message-----

> From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> Sent: 2021年6月9日 9:57

> To: Joakim Zhang <qiangqing.zhang@nxp.com>

> Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;

> andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;

> f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;

> netdev@vger.kernel.org; devicetree@vger.kernel.org;

> linux-kernel@vger.kernel.org

> Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt property to

> enable ALDPS mode

> 

> On Tue, 8 Jun 2021 10:14:40 +0000

> Joakim Zhang <qiangqing.zhang@nxp.com> wrote:

> 

> 

> >

> >

> > Hi Jisheng,

> 

> Hi,

> 

> >

> > > -----Original Message-----

> > > From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> > > Sent: 2021年6月8日 17:51

> > > To: Joakim Zhang <qiangqing.zhang@nxp.com>

> > > Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;

> > > andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;

> > > f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;

> > > netdev@vger.kernel.org; devicetree@vger.kernel.org;

> > > linux-kernel@vger.kernel.org

> > > Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt

> > > property to enable ALDPS mode

> > >

> > > On Tue,  8 Jun 2021 11:15:34 +0800

> > > Joakim Zhang <qiangqing.zhang@nxp.com> wrote:

> > >

> > >

> > > >

> > > >

> > > > If enable Advance Link Down Power Saving (ALDPS) mode, it will

> > > > change crystal/clock behavior, which cause RXC clock stop for

> > > > dozens to hundreds of miliseconds. This is comfirmed by Realtek

> > > > engineer. For some MACs, it needs RXC clock to support RX logic,

> > > > after this patch, PHY can generate continuous RXC clock during

> auto-negotiation.

> > > >

> > > > ALDPS default is disabled after hardware reset, it's more

> > > > reasonable to add a property to enable this feature, since ALDPS

> > > > would introduce side

> > > effect.

> > > > This patch adds dt property "realtek,aldps-enable" to enable ALDPS

> > > > mode per users' requirement.

> > > >

> > > > Jisheng Zhang enables this feature, changes the default behavior.

> > > > Since mine patch breaks the rule that new implementation should

> > > > not break existing design, so Cc'ed let him know to see if it can be

> accepted.

> > > >

> > > > Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> > > > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>

> > > > ---

> > > >  drivers/net/phy/realtek.c | 20 +++++++++++++++++---

> > > >  1 file changed, 17 insertions(+), 3 deletions(-)

> > > >

> > > > diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c

> > > > index ca258f2a9613..79dc55bb4091 100644

> > > > --- a/drivers/net/phy/realtek.c

> > > > +++ b/drivers/net/phy/realtek.c

> > > > @@ -76,6 +76,7 @@ MODULE_AUTHOR("Johnson Leung");

> > > > MODULE_LICENSE("GPL");

> > > >

> > > >  struct rtl821x_priv {

> > > > +       u16 phycr1;

> > > >         u16 phycr2;

> > > >  };

> > > >

> > > > @@ -98,6 +99,14 @@ static int rtl821x_probe(struct phy_device

> *phydev)

> > > >         if (!priv)

> > > >                 return -ENOMEM;

> > > >

> > > > +       priv->phycr1 = phy_read_paged(phydev, 0xa43,

> > > RTL8211F_PHYCR1);

> > > > +       if (priv->phycr1 < 0)

> > > > +               return priv->phycr1;

> > > > +

> > > > +       priv->phycr1 &= (RTL8211F_ALDPS_PLL_OFF |

> > > > + RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF);

> 

> I believe your intention is

> 

> priv->phycr1 &= ~(RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE |

> priv->RTL8211F_ALDPS_XTAL_OFF);

> However, this is not necessary. See below.


No, mine intention is to read back this three bits what the register contained.

> > >

> > > priv->phycr1 is 0 by default, so above 5 LoCs can be removed

> >

> > The intention of this is to take bootloader into account. Such as uboot

> configure the PHY before.

> 

> The last param "set" of phy_modify_paged_changed() means *bit mask of bits

> to set* If we don't want to enable ALDPS, 0 is enough.

> 

> Even if uboot configured the PHY before linux, I believe

> phy_modify_paged_changed() can clear ALDPS bits w/o above 5 LoCs.


The logic is:
1) read back these three bits from the register.
2) if linux set "realtek,aldps-enable", assert these three bit; if not, keep these three bits read before.
3) call phy_modify_paged_changed() to configure, "mask" parameter to clear these three bits first, "set" parameter to assert these three bits per the result of step 2.

So, if step 1 read back the value is that these three bits are asserted, then in step 3, it will first clear these three bits and assert these three bits again. The result is ALDPS is enabled even without " realtek,aldps-enable " in DT.

Best Regards,
Joakim Zhang
> Thanks

> 

> >

> > Best Regards,

> > Joakim Zhang

> > > > +       if (of_property_read_bool(dev->of_node,

> "realtek,aldps-enable"))

> > > > +               priv->phycr1 |= RTL8211F_ALDPS_PLL_OFF |

> > > > + RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF;

> > > > +

> > > >         priv->phycr2 = phy_read_paged(phydev, 0xa43,

> > > RTL8211F_PHYCR2);

> > > >         if (priv->phycr2 < 0)

> > > >                 return priv->phycr2; @@ -324,11 +333,16 @@ static

> > > > int rtl8211f_config_init(struct phy_device

> > > *phydev)

> > > >         struct rtl821x_priv *priv = phydev->priv;

> > > >         struct device *dev = &phydev->mdio.dev;

> > > >         u16 val_txdly, val_rxdly;

> > > > -       u16 val;

> > > >         int ret;

> > > >

> > > > -       val = RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_PLL_OFF |

> > > RTL8211F_ALDPS_XTAL_OFF;

> > > > -       phy_modify_paged_changed(phydev, 0xa43, RTL8211F_PHYCR1,

> val,

> > > val);

> > > > +       ret = phy_modify_paged_changed(phydev, 0xa43,

> > > RTL8211F_PHYCR1,

> > > > +

> RTL8211F_ALDPS_PLL_OFF |

> > > RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF,

> > > > +                                      priv->phycr1);

> > > > +       if (ret < 0) {

> > > > +               dev_err(dev, "aldps mode  configuration

> failed: %pe\n",

> > > > +                       ERR_PTR(ret));

> > > > +               return ret;

> > > > +       }

> > > >

> > > >         switch (phydev->interface) {

> > > >         case PHY_INTERFACE_MODE_RGMII:

> > > > --

> > > > 2.17.1

> > > >

> >
Jisheng Zhang June 9, 2021, 3:04 a.m. UTC | #4 
On Wed, 9 Jun 2021 02:51:11 +0000
Joakim Zhang <qiangqing.zhang@nxp.com> wrote:

> CAUTION: Email originated externally, do not click links or open attachments unless you recognize the sender and know the content is safe.
> 
> 
> Hi Jisheng,
> 
> > -----Original Message-----
> > From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> > Sent: 2021年6月9日 9:57
> > To: Joakim Zhang <qiangqing.zhang@nxp.com>
> > Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;
> > andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;
> > f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;
> > netdev@vger.kernel.org; devicetree@vger.kernel.org;
> > linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt property to
> > enable ALDPS mode
> >
> > On Tue, 8 Jun 2021 10:14:40 +0000
> > Joakim Zhang <qiangqing.zhang@nxp.com> wrote:
> >
> >  
> > >
> > >
> > > Hi Jisheng,  
> >
> > Hi,
> >  
> > >  
> > > > -----Original Message-----
> > > > From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> > > > Sent: 2021年6月8日 17:51
> > > > To: Joakim Zhang <qiangqing.zhang@nxp.com>
> > > > Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;
> > > > andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;
> > > > f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;
> > > > netdev@vger.kernel.org; devicetree@vger.kernel.org;
> > > > linux-kernel@vger.kernel.org
> > > > Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt
> > > > property to enable ALDPS mode
> > > >
> > > > On Tue,  8 Jun 2021 11:15:34 +0800
> > > > Joakim Zhang <qiangqing.zhang@nxp.com> wrote:
> > > >
> > > >  
> > > > >
> > > > >
> > > > > If enable Advance Link Down Power Saving (ALDPS) mode, it will
> > > > > change crystal/clock behavior, which cause RXC clock stop for
> > > > > dozens to hundreds of miliseconds. This is comfirmed by Realtek
> > > > > engineer. For some MACs, it needs RXC clock to support RX logic,
> > > > > after this patch, PHY can generate continuous RXC clock during  
> > auto-negotiation.  
> > > > >
> > > > > ALDPS default is disabled after hardware reset, it's more
> > > > > reasonable to add a property to enable this feature, since ALDPS
> > > > > would introduce side  
> > > > effect.  
> > > > > This patch adds dt property "realtek,aldps-enable" to enable ALDPS
> > > > > mode per users' requirement.
> > > > >
> > > > > Jisheng Zhang enables this feature, changes the default behavior.
> > > > > Since mine patch breaks the rule that new implementation should
> > > > > not break existing design, so Cc'ed let him know to see if it can be  
> > accepted.  
> > > > >
> > > > > Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> > > > > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> > > > > ---
> > > > >  drivers/net/phy/realtek.c | 20 +++++++++++++++++---
> > > > >  1 file changed, 17 insertions(+), 3 deletions(-)
> > > > >
> > > > > diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> > > > > index ca258f2a9613..79dc55bb4091 100644
> > > > > --- a/drivers/net/phy/realtek.c
> > > > > +++ b/drivers/net/phy/realtek.c
> > > > > @@ -76,6 +76,7 @@ MODULE_AUTHOR("Johnson Leung");
> > > > > MODULE_LICENSE("GPL");
> > > > >
> > > > >  struct rtl821x_priv {
> > > > > +       u16 phycr1;
> > > > >         u16 phycr2;
> > > > >  };
> > > > >
> > > > > @@ -98,6 +99,14 @@ static int rtl821x_probe(struct phy_device  
> > *phydev)  
> > > > >         if (!priv)
> > > > >                 return -ENOMEM;
> > > > >
> > > > > +       priv->phycr1 = phy_read_paged(phydev, 0xa43,  
> > > > RTL8211F_PHYCR1);  
> > > > > +       if (priv->phycr1 < 0)
> > > > > +               return priv->phycr1;
> > > > > +
> > > > > +       priv->phycr1 &= (RTL8211F_ALDPS_PLL_OFF |
> > > > > + RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF);  
> >
> > I believe your intention is
> >
> > priv->phycr1 &= ~(RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE |
> > priv->RTL8211F_ALDPS_XTAL_OFF);
> > However, this is not necessary. See below.  
> 
> No, mine intention is to read back this three bits what the register contained.
> 
> > > >
> > > > priv->phycr1 is 0 by default, so above 5 LoCs can be removed  
> > >
> > > The intention of this is to take bootloader into account. Such as uboot  
> > configure the PHY before.
> >
> > The last param "set" of phy_modify_paged_changed() means *bit mask of bits
> > to set* If we don't want to enable ALDPS, 0 is enough.
> >
> > Even if uboot configured the PHY before linux, I believe
> > phy_modify_paged_changed() can clear ALDPS bits w/o above 5 LoCs.  
> 
> The logic is:
> 1) read back these three bits from the register.
> 2) if linux set "realtek,aldps-enable", assert these three bit; if not, keep these three bits read before.
> 3) call phy_modify_paged_changed() to configure, "mask" parameter to clear these three bits first, "set" parameter to assert these three bits per the result of step 2.
> 
> So, if step 1 read back the value is that these three bits are asserted, then in step 3, it will first clear these three bits and assert these three bits again. The result is ALDPS is enabled even without " realtek,aldps-enable " in DT.
> 

Aha, I see you want to keep the ALDPS bits(maybe configured by prelinux env) untouched.
If ALDPS has been enabled by prelinux env, even there's no "realtek,aldps-enable"
in DT, the ALDPS may be keep enabled in linux. Thus the ALDPS behavior rely on
the prelinux env. I'm not sure whether this is correct or not.

IMHO, the "realtek,aldps-enable" is a "yes" or "no" bool. If it's set, ALDPS
will be enabled in linux; If it's no, ALDPS will be disabled in linux. We
should not rely on prelinux env.

Thanks
Joakim Zhang June 9, 2021, 3:55 a.m. UTC | #5 
Hi Jisheng,

> -----Original Message-----

> From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> Sent: 2021年6月9日 11:04

> To: Joakim Zhang <qiangqing.zhang@nxp.com>

> Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;

> andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;

> f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;

> netdev@vger.kernel.org; devicetree@vger.kernel.org;

> linux-kernel@vger.kernel.org

> Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt property to

> enable ALDPS mode

> 

> On Wed, 9 Jun 2021 02:51:11 +0000

> Joakim Zhang <qiangqing.zhang@nxp.com> wrote:

> 

> > CAUTION: Email originated externally, do not click links or open attachments

> unless you recognize the sender and know the content is safe.

> >

> >

> > Hi Jisheng,

> >

> > > -----Original Message-----

> > > From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> > > Sent: 2021年6月9日 9:57

> > > To: Joakim Zhang <qiangqing.zhang@nxp.com>

> > > Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;

> > > andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;

> > > f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;

> > > netdev@vger.kernel.org; devicetree@vger.kernel.org;

> > > linux-kernel@vger.kernel.org

> > > Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt

> > > property to enable ALDPS mode

> > >

> > > On Tue, 8 Jun 2021 10:14:40 +0000

> > > Joakim Zhang <qiangqing.zhang@nxp.com> wrote:

> > >

> > >

> > > >

> > > >

> > > > Hi Jisheng,

> > >

> > > Hi,

> > >

> > > >

> > > > > -----Original Message-----

> > > > > From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> > > > > Sent: 2021年6月8日 17:51

> > > > > To: Joakim Zhang <qiangqing.zhang@nxp.com>

> > > > > Cc: davem@davemloft.net; kuba@kernel.org; robh+dt@kernel.org;

> > > > > andrew@lunn.ch; hkallweit1@gmail.com; linux@armlinux.org.uk;

> > > > > f.fainelli@gmail.com; dl-linux-imx <linux-imx@nxp.com>;

> > > > > netdev@vger.kernel.org; devicetree@vger.kernel.org;

> > > > > linux-kernel@vger.kernel.org

> > > > > Subject: Re: [PATCH V3 net-next 3/4] net: phy: realtek: add dt

> > > > > property to enable ALDPS mode

> > > > >

> > > > > On Tue,  8 Jun 2021 11:15:34 +0800 Joakim Zhang

> > > > > <qiangqing.zhang@nxp.com> wrote:

> > > > >

> > > > >

> > > > > >

> > > > > >

> > > > > > If enable Advance Link Down Power Saving (ALDPS) mode, it will

> > > > > > change crystal/clock behavior, which cause RXC clock stop for

> > > > > > dozens to hundreds of miliseconds. This is comfirmed by

> > > > > > Realtek engineer. For some MACs, it needs RXC clock to support

> > > > > > RX logic, after this patch, PHY can generate continuous RXC

> > > > > > clock during

> > > auto-negotiation.

> > > > > >

> > > > > > ALDPS default is disabled after hardware reset, it's more

> > > > > > reasonable to add a property to enable this feature, since

> > > > > > ALDPS would introduce side

> > > > > effect.

> > > > > > This patch adds dt property "realtek,aldps-enable" to enable

> > > > > > ALDPS mode per users' requirement.

> > > > > >

> > > > > > Jisheng Zhang enables this feature, changes the default behavior.

> > > > > > Since mine patch breaks the rule that new implementation

> > > > > > should not break existing design, so Cc'ed let him know to see

> > > > > > if it can be

> > > accepted.

> > > > > >

> > > > > > Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> > > > > > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>

> > > > > > ---

> > > > > >  drivers/net/phy/realtek.c | 20 +++++++++++++++++---

> > > > > >  1 file changed, 17 insertions(+), 3 deletions(-)

> > > > > >

> > > > > > diff --git a/drivers/net/phy/realtek.c

> > > > > > b/drivers/net/phy/realtek.c index ca258f2a9613..79dc55bb4091

> > > > > > 100644

> > > > > > --- a/drivers/net/phy/realtek.c

> > > > > > +++ b/drivers/net/phy/realtek.c

> > > > > > @@ -76,6 +76,7 @@ MODULE_AUTHOR("Johnson Leung");

> > > > > > MODULE_LICENSE("GPL");

> > > > > >

> > > > > >  struct rtl821x_priv {

> > > > > > +       u16 phycr1;

> > > > > >         u16 phycr2;

> > > > > >  };

> > > > > >

> > > > > > @@ -98,6 +99,14 @@ static int rtl821x_probe(struct phy_device

> > > *phydev)

> > > > > >         if (!priv)

> > > > > >                 return -ENOMEM;

> > > > > >

> > > > > > +       priv->phycr1 = phy_read_paged(phydev, 0xa43,

> > > > > RTL8211F_PHYCR1);

> > > > > > +       if (priv->phycr1 < 0)

> > > > > > +               return priv->phycr1;

> > > > > > +

> > > > > > +       priv->phycr1 &= (RTL8211F_ALDPS_PLL_OFF |

> > > > > > + RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF);

> > >

> > > I believe your intention is

> > >

> > > priv->phycr1 &= ~(RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE |

> > > priv->RTL8211F_ALDPS_XTAL_OFF);

> > > However, this is not necessary. See below.

> >

> > No, mine intention is to read back this three bits what the register contained.

> >

> > > > >

> > > > > priv->phycr1 is 0 by default, so above 5 LoCs can be removed

> > > >

> > > > The intention of this is to take bootloader into account. Such as

> > > > uboot

> > > configure the PHY before.

> > >

> > > The last param "set" of phy_modify_paged_changed() means *bit mask

> > > of bits to set* If we don't want to enable ALDPS, 0 is enough.

> > >

> > > Even if uboot configured the PHY before linux, I believe

> > > phy_modify_paged_changed() can clear ALDPS bits w/o above 5 LoCs.

> >

> > The logic is:

> > 1) read back these three bits from the register.

> > 2) if linux set "realtek,aldps-enable", assert these three bit; if not, keep these

> three bits read before.

> > 3) call phy_modify_paged_changed() to configure, "mask" parameter to clear

> these three bits first, "set" parameter to assert these three bits per the result

> of step 2.

> >

> > So, if step 1 read back the value is that these three bits are asserted, then in

> step 3, it will first clear these three bits and assert these three bits again. The

> result is ALDPS is enabled even without " realtek,aldps-enable " in DT.

> >

> 

> Aha, I see you want to keep the ALDPS bits(maybe configured by prelinux env)

> untouched.

> If ALDPS has been enabled by prelinux env, even there's no

> "realtek,aldps-enable"

> in DT, the ALDPS may be keep enabled in linux. Thus the ALDPS behavior rely on

> the prelinux env. I'm not sure whether this is correct or not.

> 

> IMHO, the "realtek,aldps-enable" is a "yes" or "no" bool. If it's set, ALDPS will

> be enabled in linux; If it's no, ALDPS will be disabled in linux. We should not rely

> on prelinux env.


You can refer to below V1 comments, we may not take enough cases into account, others may care about boot loader. 
https://lkml.org/lkml/2021/6/1/264

Anyway, keep the original value in registers should not have side effects. Thanks for your reviewing, and I saw this patch set has been
accepted, if you want to improve this code, I am happy to review and test your patch.

Best Regards,
Joakim Zhang
> Thanks
Andrew Lunn June 9, 2021, 12:17 p.m. UTC | #6 
> Aha, I see you want to keep the ALDPS bits(maybe configured by prelinux env) untouched.

> If ALDPS has been enabled by prelinux env, even there's no "realtek,aldps-enable"

> in DT, the ALDPS may be keep enabled in linux. Thus the ALDPS behavior rely on

> the prelinux env. I'm not sure whether this is correct or not.

> 

> IMHO, the "realtek,aldps-enable" is a "yes" or "no" bool. If it's set, ALDPS

> will be enabled in linux; If it's no, ALDPS will be disabled in linux. We

> should not rely on prelinux env.


If you look at V1 of this patch, you will see i commented that maybe
it needs to be a tristate, not a boolean. Disable it, enable it, leave
it as is. If we do need the third state, we can add it latter.

There is something to be said for not relying on the bootloader. But
the hardware default appears to be ALDPS enabled. So this case seems
reasonably safe.

	   Andrew
diff mbox series

Patch

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index ca258f2a9613..79dc55bb4091 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -76,6 +76,7 @@  MODULE_AUTHOR("Johnson Leung");
 MODULE_LICENSE("GPL");
 
 struct rtl821x_priv {
+	u16 phycr1;
 	u16 phycr2;
 };
 
@@ -98,6 +99,14 @@  static int rtl821x_probe(struct phy_device *phydev)
 	if (!priv)
 		return -ENOMEM;
 
+	priv->phycr1 = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR1);
+	if (priv->phycr1 < 0)
+		return priv->phycr1;
+
+	priv->phycr1 &= (RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF);
+	if (of_property_read_bool(dev->of_node, "realtek,aldps-enable"))
+		priv->phycr1 |= RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF;
+
 	priv->phycr2 = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR2);
 	if (priv->phycr2 < 0)
 		return priv->phycr2;
@@ -324,11 +333,16 @@  static int rtl8211f_config_init(struct phy_device *phydev)
 	struct rtl821x_priv *priv = phydev->priv;
 	struct device *dev = &phydev->mdio.dev;
 	u16 val_txdly, val_rxdly;
-	u16 val;
 	int ret;
 
-	val = RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_XTAL_OFF;
-	phy_modify_paged_changed(phydev, 0xa43, RTL8211F_PHYCR1, val, val);
+	ret = phy_modify_paged_changed(phydev, 0xa43, RTL8211F_PHYCR1,
+				       RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF,
+				       priv->phycr1);
+	if (ret < 0) {
+		dev_err(dev, "aldps mode  configuration failed: %pe\n",
+			ERR_PTR(ret));
+		return ret;
+	}
 
 	switch (phydev->interface) {
 	case PHY_INTERFACE_MODE_RGMII: