[PATCH 1/2] net: phy: micrel: Discern KSZ8051 and KSZ8795 PHYs

[PATCH 1/2] net: phy: micrel: Discern KSZ8051 and KSZ8795 PHYs

[Marek Vasut]

The KSZ8051 PHY and the KSZ8794/KSZ8795/KSZ8765 switch share exactly the
same PHY ID. Since KSZ8051 is higher in the ksphy_driver[] list of PHYs
in the micrel PHY driver, it is used even with the KSZ87xx switch. This
is wrong, since the KSZ8051 configures registers of the PHY which are
not present on the simplified KSZ87xx switch PHYs and misconfigures
other registers of the KSZ87xx switch PHYs.

Fortunatelly, it is possible to tell apart the KSZ8051 PHY from the
KSZ87xx switch by checking the Basic Status register Bit 0, which is
read-only and indicates presence of the Extended Capability Registers.
The KSZ8051 PHY has those registers while the KSZ87xx switch does not.

This patch implements simple check for the presence of this bit for
both the KSZ8051 PHY and KSZ87xx switch, to let both use the correct
PHY driver instance.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: David S. Miller <davem@davemloft.net>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: George McCollister <george.mccollister@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Cc: Woojung Huh <woojung.huh@microchip.com>
---
NOTE: It was also suggested to populate phydev->dev_flags to discern
      the PHY from the switch, this does not work for setups where
      the switch is used as a PHY without a DSA driver. Checking the
      BMSR Bit 0 for Extended Capability Register works for both DSA
      and non-DSA usecase.
---
 drivers/net/phy/micrel.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 2fea5541c35a..54d483de024f 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -341,6 +341,22 @@ static int ksz8041_config_aneg(struct phy_device *phydev)
 	return genphy_config_aneg(phydev);
 }
 
+static int ksz8051_match_phy_device(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = phy_read(phydev, MII_BMSR);
+	if (ret < 0)
+		return ret;
+
+	/* KSZ8051 PHY and KSZ8794/KSZ8795/KSZ8765 switch share the same
+	 * exact PHY ID. However, they can be told apart by the extended
+	 * capability registers presence. The KSZ8051 PHY has them while
+	 * the switch does not.
+	 */
+	return ret & BMSR_ERCAP;
+}
+
 static int ksz8081_config_init(struct phy_device *phydev)
 {
 	/* KSZPHY_OMSO_FACTORY_TEST is set at de-assertion of the reset line
@@ -364,6 +380,18 @@ static int ksz8061_config_init(struct phy_device *phydev)
 	return kszphy_config_init(phydev);
 }
 
+static int ksz8795_match_phy_device(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = phy_read(phydev, MII_BMSR);
+	if (ret < 0)
+		return ret;
+
+	/* See comment in ksz8051_match_phy_device() for details. */
+	return !(ret & BMSR_ERCAP);
+}
+
 static int ksz9021_load_values_from_of(struct phy_device *phydev,
 				       const struct device_node *of_node,
 				       u16 reg,
@@ -1029,6 +1057,7 @@ static struct phy_driver ksphy_driver[] = {
 	.get_sset_count = kszphy_get_sset_count,
 	.get_strings	= kszphy_get_strings,
 	.get_stats	= kszphy_get_stats,
+	.match_phy_device = ksz8051_match_phy_device,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 }, {
@@ -1148,6 +1177,7 @@ static struct phy_driver ksphy_driver[] = {
 	.config_init	= kszphy_config_init,
 	.config_aneg	= ksz8873mll_config_aneg,
 	.read_status	= ksz8873mll_read_status,
+	.match_phy_device = ksz8795_match_phy_device,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 }, {
-- 
2.23.0

[PATCH 2/2] net: phy: micrel: Update KSZ87xx PHY name

[Marek Vasut]

The KSZ8795 PHY ID is in fact used by KSZ8794/KSZ8795/KSZ8765 switches.
Update the PHY ID and name to reflect that, as this family of switches
is commonly refered to as KSZ87xx

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: David S. Miller <davem@davemloft.net>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: George McCollister <george.mccollister@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Cc: Woojung Huh <woojung.huh@microchip.com>
---
 drivers/net/phy/micrel.c   | 4 ++--
 include/linux/micrel_phy.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 54d483de024f..e6be7b2516f3 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -1170,9 +1170,9 @@ static struct phy_driver ksphy_driver[] = {
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 }, {
-	.phy_id		= PHY_ID_KSZ8795,
+	.phy_id		= PHY_ID_KSZ87XX,
 	.phy_id_mask	= MICREL_PHY_ID_MASK,
-	.name		= "Micrel KSZ8795",
+	.name		= "Micrel KSZ87XX Switch",
 	/* PHY_BASIC_FEATURES */
 	.config_init	= kszphy_config_init,
 	.config_aneg	= ksz8873mll_config_aneg,
diff --git a/include/linux/micrel_phy.h b/include/linux/micrel_phy.h
index ad24554f11f9..75f880c25bb8 100644
--- a/include/linux/micrel_phy.h
+++ b/include/linux/micrel_phy.h
@@ -31,7 +31,7 @@
 #define PHY_ID_KSZ886X		0x00221430
 #define PHY_ID_KSZ8863		0x00221435
 
-#define PHY_ID_KSZ8795		0x00221550
+#define PHY_ID_KSZ87XX		0x00221550
 
 #define	PHY_ID_KSZ9477		0x00221631
 
-- 
2.23.0

Re: [PATCH 1/2] net: phy: micrel: Discern KSZ8051 and KSZ8795 PHYs

[Heiner Kallweit]

On 10.10.2019 21:12, Marek Vasut wrote:
> The KSZ8051 PHY and the KSZ8794/KSZ8795/KSZ8765 switch share exactly the
> same PHY ID. Since KSZ8051 is higher in the ksphy_driver[] list of PHYs
> in the micrel PHY driver, it is used even with the KSZ87xx switch. This
> is wrong, since the KSZ8051 configures registers of the PHY which are
> not present on the simplified KSZ87xx switch PHYs and misconfigures
> other registers of the KSZ87xx switch PHYs.
> 
> Fortunatelly, it is possible to tell apart the KSZ8051 PHY from the
> KSZ87xx switch by checking the Basic Status register Bit 0, which is
> read-only and indicates presence of the Extended Capability Registers.
> The KSZ8051 PHY has those registers while the KSZ87xx switch does not.
> 
> This patch implements simple check for the presence of this bit for
> both the KSZ8051 PHY and KSZ87xx switch, to let both use the correct
> PHY driver instance.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Andrew Lunn <andrew@lunn.ch>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Florian Fainelli <f.fainelli@gmail.com>
> Cc: George McCollister <george.mccollister@gmail.com>
> Cc: Heiner Kallweit <hkallweit1@gmail.com>
> Cc: Tristram Ha <Tristram.Ha@microchip.com>
> Cc: Woojung Huh <woojung.huh@microchip.com>
> ---
> NOTE: It was also suggested to populate phydev->dev_flags to discern
>       the PHY from the switch, this does not work for setups where
>       the switch is used as a PHY without a DSA driver. Checking the
>       BMSR Bit 0 for Extended Capability Register works for both DSA
>       and non-DSA usecase.
> ---
>  drivers/net/phy/micrel.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> index 2fea5541c35a..54d483de024f 100644
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -341,6 +341,22 @@ static int ksz8041_config_aneg(struct phy_device *phydev)
>  	return genphy_config_aneg(phydev);
>  }
>  
> +static int ksz8051_match_phy_device(struct phy_device *phydev)
> +{
> +	int ret;
> +
> +	ret = phy_read(phydev, MII_BMSR);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* KSZ8051 PHY and KSZ8794/KSZ8795/KSZ8765 switch share the same
> +	 * exact PHY ID. However, they can be told apart by the extended
> +	 * capability registers presence. The KSZ8051 PHY has them while
> +	 * the switch does not.
> +	 */
> +	return ret & BMSR_ERCAP;

Idea and approach are right, but as-is could result in this driver
matching any (even non-Micrel) PHY devices with this bit set. You have
to check the PHY ID too. See Realtek PHY driver for an example.

> +}
> +
>  static int ksz8081_config_init(struct phy_device *phydev)
>  {
>  	/* KSZPHY_OMSO_FACTORY_TEST is set at de-assertion of the reset line
> @@ -364,6 +380,18 @@ static int ksz8061_config_init(struct phy_device *phydev)
>  	return kszphy_config_init(phydev);
>  }
>  
> +static int ksz8795_match_phy_device(struct phy_device *phydev)
> +{
> +	int ret;
> +
> +	ret = phy_read(phydev, MII_BMSR);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* See comment in ksz8051_match_phy_device() for details. */
> +	return !(ret & BMSR_ERCAP);
> +}
> +
>  static int ksz9021_load_values_from_of(struct phy_device *phydev,
>  				       const struct device_node *of_node,
>  				       u16 reg,
> @@ -1029,6 +1057,7 @@ static struct phy_driver ksphy_driver[] = {
>  	.get_sset_count = kszphy_get_sset_count,
>  	.get_strings	= kszphy_get_strings,
>  	.get_stats	= kszphy_get_stats,
> +	.match_phy_device = ksz8051_match_phy_device,

If callback match_phy_device is implemented, then you can remove
phy_id and phy_id_mask. Check phy_bus_match().

>  	.suspend	= genphy_suspend,
>  	.resume		= genphy_resume,
>  }, {
> @@ -1148,6 +1177,7 @@ static struct phy_driver ksphy_driver[] = {
>  	.config_init	= kszphy_config_init,
>  	.config_aneg	= ksz8873mll_config_aneg,
>  	.read_status	= ksz8873mll_read_status,
> +	.match_phy_device = ksz8795_match_phy_device,
>  	.suspend	= genphy_suspend,
>  	.resume		= genphy_resume,
>  }, {
> 

Re: [PATCH 1/2] net: phy: micrel: Discern KSZ8051 and KSZ8795 PHYs

[David Miller]

Please respin with a proper cover letter and appropriate Fixes:
tag(s).

Thank you.