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[RFC,net-next,03/10] net: dsa: microchip: add common 100/10Mbps selection function

Message ID 20220712160308.13253-4-arun.ramadoss@microchip.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: dsa: microchip: add support for phylink mac config and link up | expand

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Commit Message

Arun Ramadoss July 12, 2022, 4:03 p.m. UTC
This patch adds the function for configuring the 100/10Mbps speed
selection for the ksz switches. KSZ8795 switch uses Global control 4
register 0x06 bit 4 for choosing 100/10Mpbs. Other switches uses xMII
control 1 0xN300 for it.
For KSZ8795, if the bit is set then 10Mbps is chosen and if bit is
clear then 100Mbps chosen. For all other switches it is other way
around, if the bit is set then 100Mbps is chosen.
So, this patch add the generic function for ksz switch to select the
100/10Mbps speed selection. While configuring, first it disables the
gigabit functionality and then configure the respective speed.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
---
 drivers/net/dsa/microchip/ksz9477_reg.h  |  1 -
 drivers/net/dsa/microchip/ksz_common.c   | 29 ++++++++++++++++++++++++
 drivers/net/dsa/microchip/ksz_common.h   |  6 +++++
 drivers/net/dsa/microchip/lan937x_main.c | 14 ++++--------
 drivers/net/dsa/microchip/lan937x_reg.h  |  1 -
 5 files changed, 40 insertions(+), 11 deletions(-)

Comments

Vladimir Oltean July 19, 2022, 10:48 a.m. UTC | #1
On Tue, Jul 12, 2022 at 09:33:01PM +0530, Arun Ramadoss wrote:
> This patch adds the function for configuring the 100/10Mbps speed
> selection for the ksz switches. KSZ8795 switch uses Global control 4
> register 0x06 bit 4 for choosing 100/10Mpbs. Other switches uses xMII
> control 1 0xN300 for it.
> For KSZ8795, if the bit is set then 10Mbps is chosen and if bit is
> clear then 100Mbps chosen. For all other switches it is other way
> around, if the bit is set then 100Mbps is chosen.
> So, this patch add the generic function for ksz switch to select the
> 100/10Mbps speed selection. While configuring, first it disables the
> gigabit functionality and then configure the respective speed.
> 
> Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
> ---
>  drivers/net/dsa/microchip/ksz9477_reg.h  |  1 -
>  drivers/net/dsa/microchip/ksz_common.c   | 29 ++++++++++++++++++++++++
>  drivers/net/dsa/microchip/ksz_common.h   |  6 +++++
>  drivers/net/dsa/microchip/lan937x_main.c | 14 ++++--------
>  drivers/net/dsa/microchip/lan937x_reg.h  |  1 -
>  5 files changed, 40 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h b/drivers/net/dsa/microchip/ksz9477_reg.h
> index f23ed4809e47..2649fdf0bae1 100644
> --- a/drivers/net/dsa/microchip/ksz9477_reg.h
> +++ b/drivers/net/dsa/microchip/ksz9477_reg.h
> @@ -1179,7 +1179,6 @@
>  
>  #define PORT_SGMII_SEL			BIT(7)
>  #define PORT_MII_FULL_DUPLEX		BIT(6)
> -#define PORT_MII_100MBIT		BIT(4)
>  #define PORT_GRXC_ENABLE		BIT(0)
>  
>  #define REG_PORT_XMII_CTRL_1		0x0301
> diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
> index 5ebcd87fc531..f41cd2801210 100644
> --- a/drivers/net/dsa/microchip/ksz_common.c
> +++ b/drivers/net/dsa/microchip/ksz_common.c
> @@ -256,6 +256,7 @@ static const u16 ksz8795_regs[] = {
>  	[S_START_CTRL]			= 0x01,
>  	[S_BROADCAST_CTRL]		= 0x06,
>  	[S_MULTICAST_CTRL]		= 0x04,
> +	[P_XMII_CTRL_0]			= 0x06,
>  	[P_XMII_CTRL_1]			= 0x56,
>  };
>  
> @@ -284,6 +285,8 @@ static const u32 ksz8795_masks[] = {
>  static const u8 ksz8795_values[] = {
>  	[P_MII_1GBIT]			= 1,
>  	[P_MII_NOT_1GBIT]		= 0,
> +	[P_MII_100MBIT]			= 0,
> +	[P_MII_10MBIT]			= 1,

Can you namespace P_GMII_1GBIT/P_GMII_NOT_1GBIT separately from
P_MII_100MBIT/P_MII_10MBIT? Otherwise it's not obvious that the first
set writes to regs[P_XMII_CTRL_1] and the other to regs[P_XMII_CTRL_0].

>  };
>  
>  static const u8 ksz8795_shifts[] = {
> @@ -356,6 +359,7 @@ static const u16 ksz9477_regs[] = {
>  	[S_START_CTRL]			= 0x0300,
>  	[S_BROADCAST_CTRL]		= 0x0332,
>  	[S_MULTICAST_CTRL]		= 0x0331,
> +	[P_XMII_CTRL_0]			= 0x0300,
>  	[P_XMII_CTRL_1]			= 0x0301,
>  };
>  
> @@ -371,11 +375,15 @@ static const u8 ksz9477_shifts[] = {
>  static const u8 ksz9477_values[] = {
>  	[P_MII_1GBIT]			= 0,
>  	[P_MII_NOT_1GBIT]		= 1,
> +	[P_MII_100MBIT]			= 1,
> +	[P_MII_10MBIT]			= 0,
>  };
>  
>  static const u8 ksz9893_values[] = {
>  	[P_MII_1GBIT]			= 1,
>  	[P_MII_NOT_1GBIT]		= 0,
> +	[P_MII_100MBIT]			= 1,
> +	[P_MII_10MBIT]			= 0,
>  };
>  
>  static const u32 lan937x_masks[] = {
> @@ -1418,6 +1426,27 @@ void ksz_set_gbit(struct ksz_device *dev, int port, bool gbit)
>  	ksz_pwrite8(dev, port, regs[P_XMII_CTRL_1], data8);
>  }
>  
> +void ksz_set_100_10mbit(struct ksz_device *dev, int port, int speed)
> +{
> +	const u8 *bitval = dev->info->bitval;
> +	const u16 *regs = dev->info->regs;
> +	u8 data8;
> +
> +	ksz_pread8(dev, port, regs[P_XMII_CTRL_0], &data8);
> +
> +	data8 &= ~P_MII_100MBIT_M;
> +
> +	ksz_set_gbit(dev, port, false);
> +
> +	if (speed == SPEED_100)
> +		data8 |= FIELD_PREP(P_MII_100MBIT_M, bitval[P_MII_100MBIT]);
> +	else
> +		data8 |= FIELD_PREP(P_MII_100MBIT_M, bitval[P_MII_10MBIT]);
> +
> +	/* Write the updated value */
> +	ksz_pwrite8(dev, port, regs[P_XMII_CTRL_0], data8);
> +}
> +
>  static void ksz_phylink_mac_link_up(struct dsa_switch *ds, int port,
>  				    unsigned int mode,
>  				    phy_interface_t interface,
> diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
> index a76dfef6309c..f1fa6feca559 100644
> --- a/drivers/net/dsa/microchip/ksz_common.h
> +++ b/drivers/net/dsa/microchip/ksz_common.h
> @@ -172,6 +172,7 @@ enum ksz_regs {
>  	S_START_CTRL,
>  	S_BROADCAST_CTRL,
>  	S_MULTICAST_CTRL,
> +	P_XMII_CTRL_0,
>  	P_XMII_CTRL_1,
>  };
>  
> @@ -215,6 +216,8 @@ enum ksz_shifts {
>  enum ksz_values {
>  	P_MII_1GBIT,
>  	P_MII_NOT_1GBIT,
> +	P_MII_100MBIT,
> +	P_MII_10MBIT,
>  };
>  
>  struct alu_struct {
> @@ -304,6 +307,7 @@ void ksz_r_mib_stats64(struct ksz_device *dev, int port);
>  void ksz_port_stp_state_set(struct dsa_switch *ds, int port, u8 state);
>  bool ksz_get_gbit(struct ksz_device *dev, int port);
>  void ksz_set_gbit(struct ksz_device *dev, int port, bool gbit);
> +void ksz_set_100_10mbit(struct ksz_device *dev, int port, int speed);
>  extern const struct ksz_chip_data ksz_switch_chips[];
>  
>  /* Common register access functions */
> @@ -468,6 +472,8 @@ static inline int is_lan937x(struct ksz_device *dev)
>  #define SW_START			0x01
>  
>  /* xMII configuration */
> +#define P_MII_100MBIT_M			BIT(4)
> +
>  #define P_MII_1GBIT_M			BIT(6)
>  
>  /* Regmap tables generation */
> diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
> index efca96b02e15..37f63110e5bb 100644
> --- a/drivers/net/dsa/microchip/lan937x_main.c
> +++ b/drivers/net/dsa/microchip/lan937x_main.c
> @@ -346,21 +346,18 @@ static void lan937x_config_interface(struct ksz_device *dev, int port,
>  				     int speed, int duplex,
>  				     bool tx_pause, bool rx_pause)
>  {
> -	u8 xmii_ctrl0, xmii_ctrl1;
> +	u8 xmii_ctrl0;
>  
>  	ksz_pread8(dev, port, REG_PORT_XMII_CTRL_0, &xmii_ctrl0);
> -	ksz_pread8(dev, port, REG_PORT_XMII_CTRL_1, &xmii_ctrl1);
>  
> -	xmii_ctrl0 &= ~(PORT_MII_100MBIT | PORT_MII_FULL_DUPLEX |
> -			PORT_MII_TX_FLOW_CTRL | PORT_MII_RX_FLOW_CTRL);
> +	xmii_ctrl0 &= ~(PORT_MII_FULL_DUPLEX | PORT_MII_TX_FLOW_CTRL |
> +			PORT_MII_RX_FLOW_CTRL);
>  
>  	if (speed == SPEED_1000)
>  		ksz_set_gbit(dev, port, true);
> -	else
> -		ksz_set_gbit(dev, port, false);
>  
> -	if (speed == SPEED_100)
> -		xmii_ctrl0 |= PORT_MII_100MBIT;
> +	if (speed == SPEED_100 || speed == SPEED_10)
> +		ksz_set_100_10mbit(dev, port, speed);

Why don't you create a single ksz_port_set_xmii_speed() entry point, and
this decides whether to call ksz_set_gbit() with true or false depending
on whether the speed was 1000, and ksz_set_100_10mbit() as appropriate?

>  
>  	if (duplex)
>  		xmii_ctrl0 |= PORT_MII_FULL_DUPLEX;
> @@ -372,7 +369,6 @@ static void lan937x_config_interface(struct ksz_device *dev, int port,
>  		xmii_ctrl0 |= PORT_MII_RX_FLOW_CTRL;
>  
>  	ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_0, xmii_ctrl0);
> -	ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_1, xmii_ctrl1);

Will these remaining ksz_pwrite8 calls to REG_PORT_XMII_CTRL_0 not
overwrite what ksz_set_gbit() is doing?

>  }
>  
>  void lan937x_phylink_get_caps(struct ksz_device *dev, int port,
> diff --git a/drivers/net/dsa/microchip/lan937x_reg.h b/drivers/net/dsa/microchip/lan937x_reg.h
> index 747295d34411..b9364f6a4f8f 100644
> --- a/drivers/net/dsa/microchip/lan937x_reg.h
> +++ b/drivers/net/dsa/microchip/lan937x_reg.h
> @@ -135,7 +135,6 @@
>  #define PORT_SGMII_SEL			BIT(7)
>  #define PORT_MII_FULL_DUPLEX		BIT(6)
>  #define PORT_MII_TX_FLOW_CTRL		BIT(5)
> -#define PORT_MII_100MBIT		BIT(4)
>  #define PORT_MII_RX_FLOW_CTRL		BIT(3)
>  #define PORT_GRXC_ENABLE		BIT(0)
>  
> -- 
> 2.36.1
>
Arun Ramadoss July 19, 2022, 3:56 p.m. UTC | #2
Hi Vladimir,
On Tue, 2022-07-19 at 13:48 +0300, Vladimir Oltean wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you
> know the content is safe
> 
> On Tue, Jul 12, 2022 at 09:33:01PM +0530, Arun Ramadoss wrote:
> > This patch adds the function for configuring the 100/10Mbps speed
> > selection for the ksz switches. KSZ8795 switch uses Global control
> > 4
> > register 0x06 bit 4 for choosing 100/10Mpbs. Other switches uses
> > xMII
> > control 1 0xN300 for it.
> > For KSZ8795, if the bit is set then 10Mbps is chosen and if bit is
> > clear then 100Mbps chosen. For all other switches it is other way
> > around, if the bit is set then 100Mbps is chosen.
> > So, this patch add the generic function for ksz switch to select
> > the
> > 100/10Mbps speed selection. While configuring, first it disables
> > the
> > gigabit functionality and then configure the respective speed.
> > 
> > Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
> > ---
> >  drivers/net/dsa/microchip/ksz9477_reg.h  |  1 -
> >  drivers/net/dsa/microchip/ksz_common.c   | 29
> > ++++++++++++++++++++++++
> >  drivers/net/dsa/microchip/ksz_common.h   |  6 +++++
> >  drivers/net/dsa/microchip/lan937x_main.c | 14 ++++--------
> >  drivers/net/dsa/microchip/lan937x_reg.h  |  1 -
> >  5 files changed, 40 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h
> > b/drivers/net/dsa/microchip/ksz9477_reg.h
> > index f23ed4809e47..2649fdf0bae1 100644
> > --- a/drivers/net/dsa/microchip/ksz9477_reg.h
> > +++ b/drivers/net/dsa/microchip/ksz9477_reg.h
> > @@ -1179,7 +1179,6 @@
> > 
> >  #define PORT_SGMII_SEL                       BIT(7)
> >  #define PORT_MII_FULL_DUPLEX         BIT(6)
> > -#define PORT_MII_100MBIT             BIT(4)
> >  #define PORT_GRXC_ENABLE             BIT(0)
> > 
> >  #define REG_PORT_XMII_CTRL_1         0x0301
> > diff --git a/drivers/net/dsa/microchip/ksz_common.c
> > b/drivers/net/dsa/microchip/ksz_common.c
> > index 5ebcd87fc531..f41cd2801210 100644
> > --- a/drivers/net/dsa/microchip/ksz_common.c
> > +++ b/drivers/net/dsa/microchip/ksz_common.c
> > @@ -256,6 +256,7 @@ static const u16 ksz8795_regs[] = {
> >       [S_START_CTRL]                  = 0x01,
> >       [S_BROADCAST_CTRL]              = 0x06,
> >       [S_MULTICAST_CTRL]              = 0x04,
> > +     [P_XMII_CTRL_0]                 = 0x06,
> >       [P_XMII_CTRL_1]                 = 0x56,
> >  };
> > 
> > @@ -284,6 +285,8 @@ static const u32 ksz8795_masks[] = {
> >  static const u8 ksz8795_values[] = {
> >       [P_MII_1GBIT]                   = 1,
> >       [P_MII_NOT_1GBIT]               = 0,
> > +     [P_MII_100MBIT]                 = 0,
> > +     [P_MII_10MBIT]                  = 1,
> 
> Can you namespace P_GMII_1GBIT/P_GMII_NOT_1GBIT separately from
> P_MII_100MBIT/P_MII_10MBIT? Otherwise it's not obvious that the first
> set writes to regs[P_XMII_CTRL_1] and the other to
> regs[P_XMII_CTRL_0].

Yes, I can do it.

> 
> >  };
> > 
> >  static const u8 ksz8795_shifts[] = {
> > @@ -356,6 +359,7 @@ static const u16 ksz9477_regs[] = {
> >       [S_START_CTRL]                  = 0x0300,
> >       [S_BROADCAST_CTRL]              = 0x0332,
> >       [S_MULTICAST_CTRL]              = 0x0331,
> > +     [P_XMII_CTRL_0]                 = 0x0300,
> >       [P_XMII_CTRL_1]                 = 0x0301,
> >  };
> > 
> > 
> > diff --git a/drivers/net/dsa/microchip/ksz_common.h
> > b/drivers/net/dsa/microchip/ksz_common.h
> > index a76dfef6309c..f1fa6feca559 100644
> > --- a/drivers/net/dsa/microchip/ksz_common.h
> > +++ b/drivers/net/dsa/microchip/ksz_common.h
> > @@ -172,6 +172,7 @@ enum ksz_regs {
> >       S_START_CTRL,
> >       S_BROADCAST_CTRL,
> >       S_MULTICAST_CTRL,
> > +     P_XMII_CTRL_0,
> >       P_XMII_CTRL_1,
> >  };
> > 
> > 
> >  /* Regmap tables generation */
> > diff --git a/drivers/net/dsa/microchip/lan937x_main.c
> > b/drivers/net/dsa/microchip/lan937x_main.c
> > index efca96b02e15..37f63110e5bb 100644
> > --- a/drivers/net/dsa/microchip/lan937x_main.c
> > +++ b/drivers/net/dsa/microchip/lan937x_main.c
> > @@ -346,21 +346,18 @@ static void lan937x_config_interface(struct
> > ksz_device *dev, int port,
> >                                    int speed, int duplex,
> >                                    bool tx_pause, bool rx_pause)
> >  {
> > -     u8 xmii_ctrl0, xmii_ctrl1;
> > +     u8 xmii_ctrl0;
> > 
> >       ksz_pread8(dev, port, REG_PORT_XMII_CTRL_0, &xmii_ctrl0);
> > -     ksz_pread8(dev, port, REG_PORT_XMII_CTRL_1, &xmii_ctrl1);
> > 
> > -     xmii_ctrl0 &= ~(PORT_MII_100MBIT | PORT_MII_FULL_DUPLEX |
> > -                     PORT_MII_TX_FLOW_CTRL |
> > PORT_MII_RX_FLOW_CTRL);
> > +     xmii_ctrl0 &= ~(PORT_MII_FULL_DUPLEX | PORT_MII_TX_FLOW_CTRL
> > |
> > +                     PORT_MII_RX_FLOW_CTRL);
> > 
> >       if (speed == SPEED_1000)
> >               ksz_set_gbit(dev, port, true);
> > -     else
> > -             ksz_set_gbit(dev, port, false);
> > 
> > -     if (speed == SPEED_100)
> > -             xmii_ctrl0 |= PORT_MII_100MBIT;
> > +     if (speed == SPEED_100 || speed == SPEED_10)
> > +             ksz_set_100_10mbit(dev, port, speed);
> 
> Why don't you create a single ksz_port_set_xmii_speed() entry point,
> and
> this decides whether to call ksz_set_gbit() with true or false
> depending
> on whether the speed was 1000, and ksz_set_100_10mbit() as
> appropriate?

Ok, I will create new function.

> > 
> >       if (duplex)
> >               xmii_ctrl0 |= PORT_MII_FULL_DUPLEX;
> > @@ -372,7 +369,6 @@ static void lan937x_config_interface(struct
> > ksz_device *dev, int port,
> >               xmii_ctrl0 |= PORT_MII_RX_FLOW_CTRL;
> > 
> >       ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_0, xmii_ctrl0);
> > -     ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_1, xmii_ctrl1);
> 
> Will these remaining ksz_pwrite8 calls to REG_PORT_XMII_CTRL_0 not
> overwrite what ksz_set_gbit() is doing?

Yes, this ksz_pwrite8 overwrites the ksz_set_gbit. But the next patch
updates the duplex and flow control separately, I tested the phylink
register configuration only after applying entire series. So I missed
this. Thanks for pointing it.
I will move the reading the xmii_ctrl0 after configuring the
ksz_set_gbit().

> 
> >  }
> > 
> >  void lan937x_phylink_get_caps(struct ksz_device *dev, int port,
> > diff --git a/drivers/net/dsa/microchip/lan937x_reg.h
> > b/drivers/net/dsa/microchip/lan937x_reg.h
> > index 747295d34411..b9364f6a4f8f 100644
> > --- a/drivers/net/dsa/microchip/lan937x_reg.h
> > +++ b/drivers/net/dsa/microchip/lan937x_reg.h
> > @@ -135,7 +135,6 @@
> >  #define PORT_SGMII_SEL                       BIT(7)
> >  #define PORT_MII_FULL_DUPLEX         BIT(6)
> >  #define PORT_MII_TX_FLOW_CTRL                BIT(5)
> > -#define PORT_MII_100MBIT             BIT(4)
> >  #define PORT_MII_RX_FLOW_CTRL                BIT(3)
> >  #define PORT_GRXC_ENABLE             BIT(0)
> > 
> > --
> > 2.36.1
> >
diff mbox series

Patch

diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h b/drivers/net/dsa/microchip/ksz9477_reg.h
index f23ed4809e47..2649fdf0bae1 100644
--- a/drivers/net/dsa/microchip/ksz9477_reg.h
+++ b/drivers/net/dsa/microchip/ksz9477_reg.h
@@ -1179,7 +1179,6 @@ 
 
 #define PORT_SGMII_SEL			BIT(7)
 #define PORT_MII_FULL_DUPLEX		BIT(6)
-#define PORT_MII_100MBIT		BIT(4)
 #define PORT_GRXC_ENABLE		BIT(0)
 
 #define REG_PORT_XMII_CTRL_1		0x0301
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 5ebcd87fc531..f41cd2801210 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -256,6 +256,7 @@  static const u16 ksz8795_regs[] = {
 	[S_START_CTRL]			= 0x01,
 	[S_BROADCAST_CTRL]		= 0x06,
 	[S_MULTICAST_CTRL]		= 0x04,
+	[P_XMII_CTRL_0]			= 0x06,
 	[P_XMII_CTRL_1]			= 0x56,
 };
 
@@ -284,6 +285,8 @@  static const u32 ksz8795_masks[] = {
 static const u8 ksz8795_values[] = {
 	[P_MII_1GBIT]			= 1,
 	[P_MII_NOT_1GBIT]		= 0,
+	[P_MII_100MBIT]			= 0,
+	[P_MII_10MBIT]			= 1,
 };
 
 static const u8 ksz8795_shifts[] = {
@@ -356,6 +359,7 @@  static const u16 ksz9477_regs[] = {
 	[S_START_CTRL]			= 0x0300,
 	[S_BROADCAST_CTRL]		= 0x0332,
 	[S_MULTICAST_CTRL]		= 0x0331,
+	[P_XMII_CTRL_0]			= 0x0300,
 	[P_XMII_CTRL_1]			= 0x0301,
 };
 
@@ -371,11 +375,15 @@  static const u8 ksz9477_shifts[] = {
 static const u8 ksz9477_values[] = {
 	[P_MII_1GBIT]			= 0,
 	[P_MII_NOT_1GBIT]		= 1,
+	[P_MII_100MBIT]			= 1,
+	[P_MII_10MBIT]			= 0,
 };
 
 static const u8 ksz9893_values[] = {
 	[P_MII_1GBIT]			= 1,
 	[P_MII_NOT_1GBIT]		= 0,
+	[P_MII_100MBIT]			= 1,
+	[P_MII_10MBIT]			= 0,
 };
 
 static const u32 lan937x_masks[] = {
@@ -1418,6 +1426,27 @@  void ksz_set_gbit(struct ksz_device *dev, int port, bool gbit)
 	ksz_pwrite8(dev, port, regs[P_XMII_CTRL_1], data8);
 }
 
+void ksz_set_100_10mbit(struct ksz_device *dev, int port, int speed)
+{
+	const u8 *bitval = dev->info->bitval;
+	const u16 *regs = dev->info->regs;
+	u8 data8;
+
+	ksz_pread8(dev, port, regs[P_XMII_CTRL_0], &data8);
+
+	data8 &= ~P_MII_100MBIT_M;
+
+	ksz_set_gbit(dev, port, false);
+
+	if (speed == SPEED_100)
+		data8 |= FIELD_PREP(P_MII_100MBIT_M, bitval[P_MII_100MBIT]);
+	else
+		data8 |= FIELD_PREP(P_MII_100MBIT_M, bitval[P_MII_10MBIT]);
+
+	/* Write the updated value */
+	ksz_pwrite8(dev, port, regs[P_XMII_CTRL_0], data8);
+}
+
 static void ksz_phylink_mac_link_up(struct dsa_switch *ds, int port,
 				    unsigned int mode,
 				    phy_interface_t interface,
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index a76dfef6309c..f1fa6feca559 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -172,6 +172,7 @@  enum ksz_regs {
 	S_START_CTRL,
 	S_BROADCAST_CTRL,
 	S_MULTICAST_CTRL,
+	P_XMII_CTRL_0,
 	P_XMII_CTRL_1,
 };
 
@@ -215,6 +216,8 @@  enum ksz_shifts {
 enum ksz_values {
 	P_MII_1GBIT,
 	P_MII_NOT_1GBIT,
+	P_MII_100MBIT,
+	P_MII_10MBIT,
 };
 
 struct alu_struct {
@@ -304,6 +307,7 @@  void ksz_r_mib_stats64(struct ksz_device *dev, int port);
 void ksz_port_stp_state_set(struct dsa_switch *ds, int port, u8 state);
 bool ksz_get_gbit(struct ksz_device *dev, int port);
 void ksz_set_gbit(struct ksz_device *dev, int port, bool gbit);
+void ksz_set_100_10mbit(struct ksz_device *dev, int port, int speed);
 extern const struct ksz_chip_data ksz_switch_chips[];
 
 /* Common register access functions */
@@ -468,6 +472,8 @@  static inline int is_lan937x(struct ksz_device *dev)
 #define SW_START			0x01
 
 /* xMII configuration */
+#define P_MII_100MBIT_M			BIT(4)
+
 #define P_MII_1GBIT_M			BIT(6)
 
 /* Regmap tables generation */
diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
index efca96b02e15..37f63110e5bb 100644
--- a/drivers/net/dsa/microchip/lan937x_main.c
+++ b/drivers/net/dsa/microchip/lan937x_main.c
@@ -346,21 +346,18 @@  static void lan937x_config_interface(struct ksz_device *dev, int port,
 				     int speed, int duplex,
 				     bool tx_pause, bool rx_pause)
 {
-	u8 xmii_ctrl0, xmii_ctrl1;
+	u8 xmii_ctrl0;
 
 	ksz_pread8(dev, port, REG_PORT_XMII_CTRL_0, &xmii_ctrl0);
-	ksz_pread8(dev, port, REG_PORT_XMII_CTRL_1, &xmii_ctrl1);
 
-	xmii_ctrl0 &= ~(PORT_MII_100MBIT | PORT_MII_FULL_DUPLEX |
-			PORT_MII_TX_FLOW_CTRL | PORT_MII_RX_FLOW_CTRL);
+	xmii_ctrl0 &= ~(PORT_MII_FULL_DUPLEX | PORT_MII_TX_FLOW_CTRL |
+			PORT_MII_RX_FLOW_CTRL);
 
 	if (speed == SPEED_1000)
 		ksz_set_gbit(dev, port, true);
-	else
-		ksz_set_gbit(dev, port, false);
 
-	if (speed == SPEED_100)
-		xmii_ctrl0 |= PORT_MII_100MBIT;
+	if (speed == SPEED_100 || speed == SPEED_10)
+		ksz_set_100_10mbit(dev, port, speed);
 
 	if (duplex)
 		xmii_ctrl0 |= PORT_MII_FULL_DUPLEX;
@@ -372,7 +369,6 @@  static void lan937x_config_interface(struct ksz_device *dev, int port,
 		xmii_ctrl0 |= PORT_MII_RX_FLOW_CTRL;
 
 	ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_0, xmii_ctrl0);
-	ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_1, xmii_ctrl1);
 }
 
 void lan937x_phylink_get_caps(struct ksz_device *dev, int port,
diff --git a/drivers/net/dsa/microchip/lan937x_reg.h b/drivers/net/dsa/microchip/lan937x_reg.h
index 747295d34411..b9364f6a4f8f 100644
--- a/drivers/net/dsa/microchip/lan937x_reg.h
+++ b/drivers/net/dsa/microchip/lan937x_reg.h
@@ -135,7 +135,6 @@ 
 #define PORT_SGMII_SEL			BIT(7)
 #define PORT_MII_FULL_DUPLEX		BIT(6)
 #define PORT_MII_TX_FLOW_CTRL		BIT(5)
-#define PORT_MII_100MBIT		BIT(4)
 #define PORT_MII_RX_FLOW_CTRL		BIT(3)
 #define PORT_GRXC_ENABLE		BIT(0)