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[net-next,v5,0/3] Add phylib support to smsc95xx

Message ID 20200826111717.405305-1-andre.edich@microchip.com
Headers show
Series Add phylib support to smsc95xx | expand

Message

Andre Edich Aug. 26, 2020, 11:17 a.m. UTC
To allow to probe external PHY drivers, this patch series adds use of
phylib to the smsc95xx driver.

Changes in v5:
- Removed all phy_read calls from the smsc95xx driver.

Changes in v4:
- Removed useless inline type qualifier.

Changes in v3:
- Moved all MDI-X functionality to the corresponding phy driver;
- Removed field internal_phy from a struct smsc95xx_priv;
- Initialized field is_internal of a struct phy_device;
- Kconfig: Added selection of PHYLIB and SMSC_PHY for USB_NET_SMSC95XX.

Changes in v2:
- Moved 'net' patches from here to the separate patch series;
- Removed redundant call of the phy_start_aneg after phy_start;
- Removed netif_dbg tracing "speed, duplex, lcladv, and rmtadv";
- mdiobus: added dependency from the usbnet device;
- Moved making of the MII address from 'phy_id' and 'idx' into the
  function mii_address;
- Moved direct MDIO accesses under condition 'if (pdata->internal_phy)',
  as they only need for the internal PHY;
- To be sure, that this set of patches is git-bisectable, tested each
  sub-set of patches to be functional for both, internal and external
  PHYs, including suspend/resume test for the 'devices'
  (5.7.8-1-ARCH, Raspberry Pi 3 Model B).

Andre Edich (3):
  smsc95xx: remove redundant function arguments
  smsc95xx: use usbnet->driver_priv
  smsc95xx: add phylib support

 drivers/net/phy/smsc.c     |  67 ++++++
 drivers/net/usb/Kconfig    |   2 +
 drivers/net/usb/smsc95xx.c | 475 +++++++++++++------------------------
 3 files changed, 238 insertions(+), 306 deletions(-)

Comments

Mans Rullgard March 28, 2021, 7:59 p.m. UTC | #1
Andre Edich <andre.edich@microchip.com> writes:

> Generally, each PHY has their own configuration and it can be done

> through an external PHY driver.  The smsc95xx driver uses only the

> hard-coded internal PHY configuration.

>

> This patch adds phylib support to probe external PHY drivers for

> configuring external PHYs.

>

> The MDI-X configuration for the internal PHYs moves from

> drivers/net/usb/smsc95xx.c to drivers/net/phy/smsc.c.

>

> Signed-off-by: Andre Edich <andre.edich@microchip.com>

> ---

>  drivers/net/phy/smsc.c     |  67 +++++++

>  drivers/net/usb/Kconfig    |   2 +

>  drivers/net/usb/smsc95xx.c | 399 +++++++++++++------------------------

>  3 files changed, 203 insertions(+), 265 deletions(-)

>

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

> index 74568ae16125..638e8c3d1f4a 100644

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

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

> @@ -21,6 +21,17 @@

>  #include <linux/netdevice.h>

>  #include <linux/smscphy.h>

>

> +/* Vendor-specific PHY Definitions */

> +/* EDPD NLP / crossover time configuration */

> +#define PHY_EDPD_CONFIG			16

> +#define PHY_EDPD_CONFIG_EXT_CROSSOVER_	0x0001

> +

> +/* Control/Status Indication Register */

> +#define SPECIAL_CTRL_STS		27

> +#define SPECIAL_CTRL_STS_OVRRD_AMDIX_	0x8000

> +#define SPECIAL_CTRL_STS_AMDIX_ENABLE_	0x4000

> +#define SPECIAL_CTRL_STS_AMDIX_STATE_	0x2000

> +

>  struct smsc_hw_stat {

>  	const char *string;

>  	u8 reg;

> @@ -96,6 +107,54 @@ static int lan911x_config_init(struct phy_device *phydev)

>  	return smsc_phy_ack_interrupt(phydev);

>  }

>

> +static int lan87xx_config_aneg(struct phy_device *phydev)

> +{

> +	int rc;

> +	int val;

> +

> +	switch (phydev->mdix_ctrl) {

> +	case ETH_TP_MDI:

> +		val = SPECIAL_CTRL_STS_OVRRD_AMDIX_;

> +		break;

> +	case ETH_TP_MDI_X:

> +		val = SPECIAL_CTRL_STS_OVRRD_AMDIX_ |

> +			SPECIAL_CTRL_STS_AMDIX_STATE_;

> +		break;

> +	case ETH_TP_MDI_AUTO:

> +		val = SPECIAL_CTRL_STS_AMDIX_ENABLE_;

> +		break;

> +	default:

> +		return genphy_config_aneg(phydev);

> +	}

> +

> +	rc = phy_read(phydev, SPECIAL_CTRL_STS);

> +	if (rc < 0)

> +		return rc;

> +

> +	rc &= ~(SPECIAL_CTRL_STS_OVRRD_AMDIX_ |

> +		SPECIAL_CTRL_STS_AMDIX_ENABLE_ |

> +		SPECIAL_CTRL_STS_AMDIX_STATE_);

> +	rc |= val;

> +	phy_write(phydev, SPECIAL_CTRL_STS, rc);

> +

> +	phydev->mdix = phydev->mdix_ctrl;

> +	return genphy_config_aneg(phydev);

> +}

> +

> +static int lan87xx_config_aneg_ext(struct phy_device *phydev)

> +{

> +	int rc;

> +

> +	/* Extend Manual AutoMDIX timer */

> +	rc = phy_read(phydev, PHY_EDPD_CONFIG);

> +	if (rc < 0)

> +		return rc;

> +

> +	rc |= PHY_EDPD_CONFIG_EXT_CROSSOVER_;

> +	phy_write(phydev, PHY_EDPD_CONFIG, rc);

> +	return lan87xx_config_aneg(phydev);

> +}

> +

>  /*

>   * The LAN87xx suffers from rare absence of the ENERGYON-bit when Ethernet cable

>   * plugs in while LAN87xx is in Energy Detect Power-Down mode. This leads to

> @@ -250,6 +309,9 @@ static struct phy_driver smsc_phy_driver[] = {

>  	.suspend	= genphy_suspend,

>  	.resume		= genphy_resume,

>  }, {

> +	/* This covers internal PHY (phy_id: 0x0007C0C3) for

> +	 * LAN9500 (PID: 0x9500), LAN9514 (PID: 0xec00), LAN9505 (PID: 0x9505)

> +	 */

>  	.phy_id		= 0x0007c0c0, /* OUI=0x00800f, Model#=0x0c */

>  	.phy_id_mask	= 0xfffffff0,

>  	.name		= "SMSC LAN8700",

> @@ -262,6 +324,7 @@ static struct phy_driver smsc_phy_driver[] = {

>  	.read_status	= lan87xx_read_status,

>  	.config_init	= smsc_phy_config_init,

>  	.soft_reset	= smsc_phy_reset,

> +	.config_aneg	= lan87xx_config_aneg,

>

>  	/* IRQ related */

>  	.ack_interrupt	= smsc_phy_ack_interrupt,

> @@ -293,6 +356,9 @@ static struct phy_driver smsc_phy_driver[] = {

>  	.suspend	= genphy_suspend,

>  	.resume		= genphy_resume,

>  }, {

> +	/* This covers internal PHY (phy_id: 0x0007C0F0) for

> +	 * LAN9500A (PID: 0x9E00), LAN9505A (PID: 0x9E01)

> +	 */

>  	.phy_id		= 0x0007c0f0, /* OUI=0x00800f, Model#=0x0f */

>  	.phy_id_mask	= 0xfffffff0,

>  	.name		= "SMSC LAN8710/LAN8720",

> @@ -306,6 +372,7 @@ static struct phy_driver smsc_phy_driver[] = {

>  	.read_status	= lan87xx_read_status,

>  	.config_init	= smsc_phy_config_init,

>  	.soft_reset	= smsc_phy_reset,

> +	.config_aneg	= lan87xx_config_aneg_ext,

>

>  	/* IRQ related */

>  	.ack_interrupt	= smsc_phy_ack_interrupt,


This change seems to be causing some trouble I'm seeing with a LAN8710A.
Specifically lan87xx_config_aneg_ext() writes to register 16 which is
not documented for LAN8710A (nor for LAN8720A).  The effect is somewhat
random.  Sometimes, the device drops to 10 Mbps while the kernel still
reports the link speed as 100 Mbps.  Other times, it doesn't work at
all.  Everything works if I change config_aneg to lan87xx_config_aneg,
like this:

diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index 10722fed666d..07c0a7e4a350 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -408,7 +408,7 @@ static struct phy_driver smsc_phy_driver[] = {
        .read_status    = lan87xx_read_status,
        .config_init    = smsc_phy_config_init,
        .soft_reset     = smsc_phy_reset,
-       .config_aneg    = lan87xx_config_aneg_ext,
+       .config_aneg    = lan87xx_config_aneg,
 
        /* IRQ related */
        .ack_interrupt  = smsc_phy_ack_interrupt,

The internal phy of the LAN9500A does have a register 16 with
documentation matching the usage in this patch.  Unfortunately, there
doesn't seem to be any way of distinguishing this from the LAN8710A
based on register values.  Anyone got any clever ideas?

-- 
Måns Rullgård
Heiner Kallweit March 28, 2021, 8:31 p.m. UTC | #2
On 28.03.2021 21:59, Måns Rullgård wrote:
> Andre Edich <andre.edich@microchip.com> writes:

> 

>> Generally, each PHY has their own configuration and it can be done

>> through an external PHY driver.  The smsc95xx driver uses only the

>> hard-coded internal PHY configuration.

>>

>> This patch adds phylib support to probe external PHY drivers for

>> configuring external PHYs.

>>

>> The MDI-X configuration for the internal PHYs moves from

>> drivers/net/usb/smsc95xx.c to drivers/net/phy/smsc.c.

>>

>> Signed-off-by: Andre Edich <andre.edich@microchip.com>

>> ---

>>  drivers/net/phy/smsc.c     |  67 +++++++

>>  drivers/net/usb/Kconfig    |   2 +

>>  drivers/net/usb/smsc95xx.c | 399 +++++++++++++------------------------

>>  3 files changed, 203 insertions(+), 265 deletions(-)

>>

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

>> index 74568ae16125..638e8c3d1f4a 100644

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

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

>> @@ -21,6 +21,17 @@

>>  #include <linux/netdevice.h>

>>  #include <linux/smscphy.h>

>>

>> +/* Vendor-specific PHY Definitions */

>> +/* EDPD NLP / crossover time configuration */

>> +#define PHY_EDPD_CONFIG			16

>> +#define PHY_EDPD_CONFIG_EXT_CROSSOVER_	0x0001

>> +

>> +/* Control/Status Indication Register */

>> +#define SPECIAL_CTRL_STS		27

>> +#define SPECIAL_CTRL_STS_OVRRD_AMDIX_	0x8000

>> +#define SPECIAL_CTRL_STS_AMDIX_ENABLE_	0x4000

>> +#define SPECIAL_CTRL_STS_AMDIX_STATE_	0x2000

>> +

>>  struct smsc_hw_stat {

>>  	const char *string;

>>  	u8 reg;

>> @@ -96,6 +107,54 @@ static int lan911x_config_init(struct phy_device *phydev)

>>  	return smsc_phy_ack_interrupt(phydev);

>>  }

>>

>> +static int lan87xx_config_aneg(struct phy_device *phydev)

>> +{

>> +	int rc;

>> +	int val;

>> +

>> +	switch (phydev->mdix_ctrl) {

>> +	case ETH_TP_MDI:

>> +		val = SPECIAL_CTRL_STS_OVRRD_AMDIX_;

>> +		break;

>> +	case ETH_TP_MDI_X:

>> +		val = SPECIAL_CTRL_STS_OVRRD_AMDIX_ |

>> +			SPECIAL_CTRL_STS_AMDIX_STATE_;

>> +		break;

>> +	case ETH_TP_MDI_AUTO:

>> +		val = SPECIAL_CTRL_STS_AMDIX_ENABLE_;

>> +		break;

>> +	default:

>> +		return genphy_config_aneg(phydev);

>> +	}

>> +

>> +	rc = phy_read(phydev, SPECIAL_CTRL_STS);

>> +	if (rc < 0)

>> +		return rc;

>> +

>> +	rc &= ~(SPECIAL_CTRL_STS_OVRRD_AMDIX_ |

>> +		SPECIAL_CTRL_STS_AMDIX_ENABLE_ |

>> +		SPECIAL_CTRL_STS_AMDIX_STATE_);

>> +	rc |= val;

>> +	phy_write(phydev, SPECIAL_CTRL_STS, rc);

>> +

>> +	phydev->mdix = phydev->mdix_ctrl;

>> +	return genphy_config_aneg(phydev);

>> +}

>> +

>> +static int lan87xx_config_aneg_ext(struct phy_device *phydev)

>> +{

>> +	int rc;

>> +

>> +	/* Extend Manual AutoMDIX timer */

>> +	rc = phy_read(phydev, PHY_EDPD_CONFIG);

>> +	if (rc < 0)

>> +		return rc;

>> +

>> +	rc |= PHY_EDPD_CONFIG_EXT_CROSSOVER_;

>> +	phy_write(phydev, PHY_EDPD_CONFIG, rc);

>> +	return lan87xx_config_aneg(phydev);

>> +}

>> +

>>  /*

>>   * The LAN87xx suffers from rare absence of the ENERGYON-bit when Ethernet cable

>>   * plugs in while LAN87xx is in Energy Detect Power-Down mode. This leads to

>> @@ -250,6 +309,9 @@ static struct phy_driver smsc_phy_driver[] = {

>>  	.suspend	= genphy_suspend,

>>  	.resume		= genphy_resume,

>>  }, {

>> +	/* This covers internal PHY (phy_id: 0x0007C0C3) for

>> +	 * LAN9500 (PID: 0x9500), LAN9514 (PID: 0xec00), LAN9505 (PID: 0x9505)

>> +	 */

>>  	.phy_id		= 0x0007c0c0, /* OUI=0x00800f, Model#=0x0c */

>>  	.phy_id_mask	= 0xfffffff0,

>>  	.name		= "SMSC LAN8700",

>> @@ -262,6 +324,7 @@ static struct phy_driver smsc_phy_driver[] = {

>>  	.read_status	= lan87xx_read_status,

>>  	.config_init	= smsc_phy_config_init,

>>  	.soft_reset	= smsc_phy_reset,

>> +	.config_aneg	= lan87xx_config_aneg,

>>

>>  	/* IRQ related */

>>  	.ack_interrupt	= smsc_phy_ack_interrupt,

>> @@ -293,6 +356,9 @@ static struct phy_driver smsc_phy_driver[] = {

>>  	.suspend	= genphy_suspend,

>>  	.resume		= genphy_resume,

>>  }, {

>> +	/* This covers internal PHY (phy_id: 0x0007C0F0) for

>> +	 * LAN9500A (PID: 0x9E00), LAN9505A (PID: 0x9E01)

>> +	 */

>>  	.phy_id		= 0x0007c0f0, /* OUI=0x00800f, Model#=0x0f */

>>  	.phy_id_mask	= 0xfffffff0,

>>  	.name		= "SMSC LAN8710/LAN8720",

>> @@ -306,6 +372,7 @@ static struct phy_driver smsc_phy_driver[] = {

>>  	.read_status	= lan87xx_read_status,

>>  	.config_init	= smsc_phy_config_init,

>>  	.soft_reset	= smsc_phy_reset,

>> +	.config_aneg	= lan87xx_config_aneg_ext,

>>

>>  	/* IRQ related */

>>  	.ack_interrupt	= smsc_phy_ack_interrupt,

> 

> This change seems to be causing some trouble I'm seeing with a LAN8710A.

> Specifically lan87xx_config_aneg_ext() writes to register 16 which is

> not documented for LAN8710A (nor for LAN8720A).  The effect is somewhat

> random.  Sometimes, the device drops to 10 Mbps while the kernel still

> reports the link speed as 100 Mbps.  Other times, it doesn't work at

> all.  Everything works if I change config_aneg to lan87xx_config_aneg,

> like this:

> 

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

> index 10722fed666d..07c0a7e4a350 100644

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

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

> @@ -408,7 +408,7 @@ static struct phy_driver smsc_phy_driver[] = {

>         .read_status    = lan87xx_read_status,

>         .config_init    = smsc_phy_config_init,

>         .soft_reset     = smsc_phy_reset,

> -       .config_aneg    = lan87xx_config_aneg_ext,

> +       .config_aneg    = lan87xx_config_aneg,

>  

>         /* IRQ related */

>         .ack_interrupt  = smsc_phy_ack_interrupt,

> 

> The internal phy of the LAN9500A does have a register 16 with

> documentation matching the usage in this patch.  Unfortunately, there

> doesn't seem to be any way of distinguishing this from the LAN8710A

> based on register values.  Anyone got any clever ideas?

> 

After reading register PHY_EDPD_CONFIG you could check whether the
read value is plausible. On the PHY's not supporting this register,
what is the read value? 0x00 or 0xff? And is this value plausible
for PHY's supporting this register?

Currently the PHY driver doesn't check the revision number
(last four bits of PHY ID). Maybe they differ.
Mans Rullgard March 28, 2021, 9:33 p.m. UTC | #3
Heiner Kallweit <hkallweit1@gmail.com> writes:

> On 28.03.2021 21:59, Måns Rullgård wrote:

>> Andre Edich <andre.edich@microchip.com> writes:

>> 

>>> Generally, each PHY has their own configuration and it can be done

>>> through an external PHY driver.  The smsc95xx driver uses only the

>>> hard-coded internal PHY configuration.

>>>

>>> This patch adds phylib support to probe external PHY drivers for

>>> configuring external PHYs.

>>>

>>> The MDI-X configuration for the internal PHYs moves from

>>> drivers/net/usb/smsc95xx.c to drivers/net/phy/smsc.c.

>>>

>>> Signed-off-by: Andre Edich <andre.edich@microchip.com>

>>> ---

>>>  drivers/net/phy/smsc.c     |  67 +++++++

>>>  drivers/net/usb/Kconfig    |   2 +

>>>  drivers/net/usb/smsc95xx.c | 399 +++++++++++++------------------------

>>>  3 files changed, 203 insertions(+), 265 deletions(-)

>>>

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

>>> index 74568ae16125..638e8c3d1f4a 100644

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

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

>>> @@ -21,6 +21,17 @@

>>>  #include <linux/netdevice.h>

>>>  #include <linux/smscphy.h>

>>>

>>> +/* Vendor-specific PHY Definitions */

>>> +/* EDPD NLP / crossover time configuration */

>>> +#define PHY_EDPD_CONFIG			16

>>> +#define PHY_EDPD_CONFIG_EXT_CROSSOVER_	0x0001

>>> +

>>> +/* Control/Status Indication Register */

>>> +#define SPECIAL_CTRL_STS		27

>>> +#define SPECIAL_CTRL_STS_OVRRD_AMDIX_	0x8000

>>> +#define SPECIAL_CTRL_STS_AMDIX_ENABLE_	0x4000

>>> +#define SPECIAL_CTRL_STS_AMDIX_STATE_	0x2000

>>> +

>>>  struct smsc_hw_stat {

>>>  	const char *string;

>>>  	u8 reg;

>>> @@ -96,6 +107,54 @@ static int lan911x_config_init(struct phy_device *phydev)

>>>  	return smsc_phy_ack_interrupt(phydev);

>>>  }

>>>

>>> +static int lan87xx_config_aneg(struct phy_device *phydev)

>>> +{

>>> +	int rc;

>>> +	int val;

>>> +

>>> +	switch (phydev->mdix_ctrl) {

>>> +	case ETH_TP_MDI:

>>> +		val = SPECIAL_CTRL_STS_OVRRD_AMDIX_;

>>> +		break;

>>> +	case ETH_TP_MDI_X:

>>> +		val = SPECIAL_CTRL_STS_OVRRD_AMDIX_ |

>>> +			SPECIAL_CTRL_STS_AMDIX_STATE_;

>>> +		break;

>>> +	case ETH_TP_MDI_AUTO:

>>> +		val = SPECIAL_CTRL_STS_AMDIX_ENABLE_;

>>> +		break;

>>> +	default:

>>> +		return genphy_config_aneg(phydev);

>>> +	}

>>> +

>>> +	rc = phy_read(phydev, SPECIAL_CTRL_STS);

>>> +	if (rc < 0)

>>> +		return rc;

>>> +

>>> +	rc &= ~(SPECIAL_CTRL_STS_OVRRD_AMDIX_ |

>>> +		SPECIAL_CTRL_STS_AMDIX_ENABLE_ |

>>> +		SPECIAL_CTRL_STS_AMDIX_STATE_);

>>> +	rc |= val;

>>> +	phy_write(phydev, SPECIAL_CTRL_STS, rc);

>>> +

>>> +	phydev->mdix = phydev->mdix_ctrl;

>>> +	return genphy_config_aneg(phydev);

>>> +}

>>> +

>>> +static int lan87xx_config_aneg_ext(struct phy_device *phydev)

>>> +{

>>> +	int rc;

>>> +

>>> +	/* Extend Manual AutoMDIX timer */

>>> +	rc = phy_read(phydev, PHY_EDPD_CONFIG);

>>> +	if (rc < 0)

>>> +		return rc;

>>> +

>>> +	rc |= PHY_EDPD_CONFIG_EXT_CROSSOVER_;

>>> +	phy_write(phydev, PHY_EDPD_CONFIG, rc);

>>> +	return lan87xx_config_aneg(phydev);

>>> +}

>>> +

>>>  /*

>>>   * The LAN87xx suffers from rare absence of the ENERGYON-bit when Ethernet cable

>>>   * plugs in while LAN87xx is in Energy Detect Power-Down mode. This leads to

>>> @@ -250,6 +309,9 @@ static struct phy_driver smsc_phy_driver[] = {

>>>  	.suspend	= genphy_suspend,

>>>  	.resume		= genphy_resume,

>>>  }, {

>>> +	/* This covers internal PHY (phy_id: 0x0007C0C3) for

>>> +	 * LAN9500 (PID: 0x9500), LAN9514 (PID: 0xec00), LAN9505 (PID: 0x9505)

>>> +	 */

>>>  	.phy_id		= 0x0007c0c0, /* OUI=0x00800f, Model#=0x0c */

>>>  	.phy_id_mask	= 0xfffffff0,

>>>  	.name		= "SMSC LAN8700",

>>> @@ -262,6 +324,7 @@ static struct phy_driver smsc_phy_driver[] = {

>>>  	.read_status	= lan87xx_read_status,

>>>  	.config_init	= smsc_phy_config_init,

>>>  	.soft_reset	= smsc_phy_reset,

>>> +	.config_aneg	= lan87xx_config_aneg,

>>>

>>>  	/* IRQ related */

>>>  	.ack_interrupt	= smsc_phy_ack_interrupt,

>>> @@ -293,6 +356,9 @@ static struct phy_driver smsc_phy_driver[] = {

>>>  	.suspend	= genphy_suspend,

>>>  	.resume		= genphy_resume,

>>>  }, {

>>> +	/* This covers internal PHY (phy_id: 0x0007C0F0) for

>>> +	 * LAN9500A (PID: 0x9E00), LAN9505A (PID: 0x9E01)

>>> +	 */

>>>  	.phy_id		= 0x0007c0f0, /* OUI=0x00800f, Model#=0x0f */

>>>  	.phy_id_mask	= 0xfffffff0,

>>>  	.name		= "SMSC LAN8710/LAN8720",

>>> @@ -306,6 +372,7 @@ static struct phy_driver smsc_phy_driver[] = {

>>>  	.read_status	= lan87xx_read_status,

>>>  	.config_init	= smsc_phy_config_init,

>>>  	.soft_reset	= smsc_phy_reset,

>>> +	.config_aneg	= lan87xx_config_aneg_ext,

>>>

>>>  	/* IRQ related */

>>>  	.ack_interrupt	= smsc_phy_ack_interrupt,

>> 

>> This change seems to be causing some trouble I'm seeing with a LAN8710A.

>> Specifically lan87xx_config_aneg_ext() writes to register 16 which is

>> not documented for LAN8710A (nor for LAN8720A).  The effect is somewhat

>> random.  Sometimes, the device drops to 10 Mbps while the kernel still

>> reports the link speed as 100 Mbps.  Other times, it doesn't work at

>> all.  Everything works if I change config_aneg to lan87xx_config_aneg,

>> like this:

>> 

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

>> index 10722fed666d..07c0a7e4a350 100644

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

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

>> @@ -408,7 +408,7 @@ static struct phy_driver smsc_phy_driver[] = {

>>         .read_status    = lan87xx_read_status,

>>         .config_init    = smsc_phy_config_init,

>>         .soft_reset     = smsc_phy_reset,

>> -       .config_aneg    = lan87xx_config_aneg_ext,

>> +       .config_aneg    = lan87xx_config_aneg,

>>  

>>         /* IRQ related */

>>         .ack_interrupt  = smsc_phy_ack_interrupt,

>> 

>> The internal phy of the LAN9500A does have a register 16 with

>> documentation matching the usage in this patch.  Unfortunately, there

>> doesn't seem to be any way of distinguishing this from the LAN8710A

>> based on register values.  Anyone got any clever ideas?

>> 

> After reading register PHY_EDPD_CONFIG you could check whether the

> read value is plausible. On the PHY's not supporting this register,

> what is the read value? 0x00 or 0xff? And is this value plausible

> for PHY's supporting this register?


On the LAN8710A I have here, it reads as 0x40.  That bit is "reserved"
without a specified value on the LAN9500A.  On LAN8740A (which also has
a different ID value), it controls Energy Efficient Ethernet

> Currently the PHY driver doesn't check the revision number (last four

> bits of PHY ID). Maybe they differ.


Even if they are different today (I don't seem to have a LAN9500A to
check), nothing guarantees that this will remain the case with future
versions of the chips.

-- 
Måns Rullgård