[RFC PATCH 1/5] net: mediatek: move MT7531 mdio to dedicated driver
Christian Marangi
ansuelsmth at gmail.com
Mon Aug 25 10:33:59 CEST 2025
On Mon, Aug 25, 2025 at 01:15:40AM +0000, Weijie Gao (高惟杰) wrote:
> On Sat, 2025-08-23 at 01:33 +0200, Christian Marangi wrote:
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >
> >
> > On Sat, Aug 23, 2025 at 01:29:15AM +0200, Christian Marangi wrote:
> > > In preparation for support of MDIO on AN7581, move the MT7531 logic
> > > to a
> > > dedicated driver and permit usage of the mdio read/write function
> > > to the
> > > mtk_eth driver.
> > >
> > > Minor changes are required to mtk_eth for this change as the
> > > dedicated
> > > MDIO driver only needs info of the GSW register and nothing else.
> > >
> > > This permits Airoha driver to make use of DM_MDIO to bind for the
> > > MT7531
> > > driver that have the same exact register.
> > >
> > > Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
> > > ---
> > > drivers/net/Kconfig | 3 +
> > > drivers/net/Makefile | 4 +
> > > drivers/net/mdio-mt7531.c | 140
> > > +++++++++++++++++++++++++++++++++++
> > > drivers/net/mdio-mt7531.h | 9 +++
> > > drivers/net/mtk_eth/Kconfig | 1 +
> > > drivers/net/mtk_eth/mt753x.c | 29 +++-----
> > > drivers/net/mtk_eth/mt753x.h | 3 +
> > > 7 files changed, 169 insertions(+), 20 deletions(-)
> > > create mode 100644 drivers/net/mdio-mt7531.c
> > > create mode 100644 drivers/net/mdio-mt7531.h
> > >
> > > diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> > > index d1cb69f85ad..9ac9bee46c9 100644
> > > --- a/drivers/net/Kconfig
> > > +++ b/drivers/net/Kconfig
> > > @@ -966,6 +966,9 @@ config TSEC_ENET
> > > This driver implements support for the (Enhanced) Three-
> > > Speed
> > > Ethernet Controller found on Freescale SoCs.
> > >
> > > +config MDIO_MT7531
> > > + bool
> > > +
> > > source "drivers/net/mtk_eth/Kconfig"
> > >
> > > config HIFEMAC_ETH
> > > diff --git a/drivers/net/Makefile b/drivers/net/Makefile
> > > index f8f9a71f815..beb7864adc2 100644
> > > --- a/drivers/net/Makefile
> > > +++ b/drivers/net/Makefile
> > > @@ -62,7 +62,11 @@ obj-$(CONFIG_LITEETH) += liteeth.o
> > > obj-$(CONFIG_MACB) += macb.o
> > > obj-$(CONFIG_MCFFEC) += mcffec.o mcfmii.o
> > > obj-$(CONFIG_MDIO_IPQ4019) += mdio-ipq4019.o
> > > +<<<<<<< HEAD
> > > obj-$(CONFIG_MDIO_GPIO_BITBANG) += mdio_gpio.o
> > > +=======
> > > +obj-$(CONFIG_MDIO_MT7531) += mdio-mt7531.o
> > > +>>>>>>> net: mediatek: move MT7531 mdio to dedicated driver
> >
> > This merge conflict slipped in and will be fixed in the next
> > revision.
> > These changes were tested locally on an AN7581 RFB board.
> >
> > > obj-$(CONFIG_MDIO_MUX_I2CREG) += mdio_mux_i2creg.o
> > > obj-$(CONFIG_MDIO_MUX_MESON_G12A) += mdio_mux_meson_g12a.o
> > > obj-$(CONFIG_MDIO_MUX_MESON_GXL) += mdio_mux_meson_gxl.o
> > > diff --git a/drivers/net/mdio-mt7531.c b/drivers/net/mdio-mt7531.c
> > > new file mode 100644
> > > index 00000000000..4772c9b5407
> > > --- /dev/null
> > > +++ b/drivers/net/mdio-mt7531.c
> > > @@ -0,0 +1,140 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +
> > > +#include <asm/io.h>
> > > +#include <dm.h>
> > > +#include <linux/bitfield.h>
> > > +#include <linux/iopoll.h>
> > > +#include <miiphy.h>
> > > +
> > > +#define MT7531_PHY_IAC 0x701c
> > > +#define MT7531_PHY_ACS_ST BIT(31)
> > > +#define MT7531_MDIO_REG_ADDR_CL22 GENMASK(29, 25)
> > > +#define MT7531_MDIO_DEV_ADDR MT7531_MDIO_REG_ADDR_
> > > CL22
> > > +#define MT7531_MDIO_PHY_ADDR GENMASK(24, 20)
> > > +#define MT7531_MDIO_CMD GENMASK(19, 18)
> > > +#define MT7531_MDIO_CMD_READ_CL45 FIELD_PREP_CONST(MT7531_MDIO_
> > > CMD, 0x3)
> > > +#define MT7531_MDIO_CMD_READ_CL22 FIELD_PREP_CONST(MT7531_MDIO_
> > > CMD, 0x2)
> > > +#define MT7531_MDIO_CMD_WRITE FIELD_PREP_CONST(MT75
> > > 31_MDIO_CMD, 0x1)
> > > +#define MT7531_MDIO_CMD_ADDR FIELD_PREP_CONST(MT75
> > > 31_MDIO_CMD, 0x0)
> > > +#define MT7531_MDIO_ST GENMASK(17, 16)
> > > +#define MT7531_MDIO_ST_CL22 FIELD_PREP_CONST(MT75
> > > 31_MDIO_ST, 0x1)
> > > +#define MT7531_MDIO_ST_CL45 FIELD_PREP_CONST(MT75
> > > 31_MDIO_ST, 0x0)
> > > +#define MT7531_MDIO_RW_DATA GENMASK(15, 0)
> > > +#define MT7531_MDIO_REG_ADDR_CL45 MT7531_MDIO_RW_DATA
> > > +
> > > +#define MT7531_MDIO_TIMEOUT 100000
> > > +#define MT7531_MDIO_SLEEP 20
> > > +
> > > +struct mt7531_mdio_priv {
> > > + phys_addr_t switch_regs;
> > > +};
> > > +
> > > +static int mt7531_mdio_wait_busy(struct mt7531_mdio_priv *priv)
> > > +{
> > > + unsigned int busy;
> > > +
> > > + return readl_poll_sleep_timeout(priv->switch_regs +
> > > MT7531_PHY_IAC,
> > > + busy, (busy &
> > > MT7531_PHY_ACS_ST) == 0,
> > > + MT7531_MDIO_SLEEP,
> > > MT7531_MDIO_TIMEOUT);
> > > +}
> > > +
> > > +int mt7531_mdio_read(struct udevice *dev, int addr, int devad, int
> > > reg)
> > > +{
> > > + struct mt7531_mdio_priv *priv = dev_get_priv(dev);
> > > + u32 val;
> > > +
> > > + if (devad != MDIO_DEVAD_NONE) {
> > > + if (mt7531_mdio_wait_busy(priv))
> > > + return -ETIMEDOUT;
> > > +
> > > + val = MT7531_PHY_ACS_ST |
> > > + MT7531_MDIO_ST_CL45 | MT7531_MDIO_CMD_ADDR |
> > > + FIELD_PREP(MT7531_MDIO_PHY_ADDR, addr) |
> > > + FIELD_PREP(MT7531_MDIO_DEV_ADDR, devad) |
> > > + FIELD_PREP(MT7531_MDIO_REG_ADDR_CL45, reg);
> > > +
> > > + writel(val, priv->switch_regs + MT7531_PHY_IAC);
> > > + }
> > > +
> > > + if (mt7531_mdio_wait_busy(priv))
> > > + return -ETIMEDOUT;
> > > +
> > > + val = MT7531_PHY_ACS_ST | FIELD_PREP(MT7531_MDIO_PHY_ADDR,
> > > addr);
> > > + if (devad != MDIO_DEVAD_NONE)
> > > + val |= MT7531_MDIO_ST_CL45 |
> > > MT7531_MDIO_CMD_READ_CL45 |
> > > + FIELD_PREP(MT7531_MDIO_DEV_ADDR, devad);
> > > + else
> > > + val |= MT7531_MDIO_ST_CL22 |
> > > MT7531_MDIO_CMD_READ_CL22 |
> > > + FIELD_PREP(MT7531_MDIO_REG_ADDR_CL22, reg);
> > > +
> > > + writel(val, priv->switch_regs + MT7531_PHY_IAC);
> > > +
> > > + if (mt7531_mdio_wait_busy(priv))
> > > + return -ETIMEDOUT;
> > > +
> > > + val = readl(priv->switch_regs + MT7531_PHY_IAC);
> > > + return val & MT7531_MDIO_RW_DATA;
> > > +}
> > > +
> > > +int mt7531_mdio_write(struct udevice *dev, int addr, int devad,
> > > + int reg, u16 value)
> > > +{
> > > + struct mt7531_mdio_priv *priv = dev_get_priv(dev);
> > > + u32 val;
> > > +
> > > + if (devad != MDIO_DEVAD_NONE) {
> > > + if (mt7531_mdio_wait_busy(priv))
> > > + return -ETIMEDOUT;
> > > +
> > > + val = MT7531_PHY_ACS_ST |
> > > + MT7531_MDIO_ST_CL45 | MT7531_MDIO_CMD_ADDR |
> > > + FIELD_PREP(MT7531_MDIO_PHY_ADDR, addr) |
> > > + FIELD_PREP(MT7531_MDIO_DEV_ADDR, devad) |
> > > + FIELD_PREP(MT7531_MDIO_REG_ADDR_CL45, reg);
> > > +
> > > + writel(val, priv->switch_regs + MT7531_PHY_IAC);
> > > + }
> > > +
> > > + if (mt7531_mdio_wait_busy(priv))
> > > + return -ETIMEDOUT;
> > > +
> > > + val = MT7531_PHY_ACS_ST | FIELD_PREP(MT7531_MDIO_PHY_ADDR,
> > > addr) |
> > > + MT7531_MDIO_CMD_WRITE | FIELD_PREP(MT7531_MDIO_RW_DATA,
> > > value);
> > > + if (devad != MDIO_DEVAD_NONE)
> > > + val |= MT7531_MDIO_ST_CL45 |
> > > + FIELD_PREP(MT7531_MDIO_DEV_ADDR, devad);
> > > + else
> > > + val |= MT7531_MDIO_ST_CL22 |
> > > + FIELD_PREP(MT7531_MDIO_REG_ADDR_CL22, reg);
> > > +
> > > + writel(val, priv->switch_regs + MT7531_PHY_IAC);
> > > +
> > > + if (mt7531_mdio_wait_busy(priv))
> > > + return -ETIMEDOUT;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static const struct mdio_ops mt7531_mdio_ops = {
> > > + .read = mt7531_mdio_read,
> > > + .write = mt7531_mdio_write,
> > > +};
> > > +
> > > +static int mt7531_mdio_probe(struct udevice *dev)
> > > +{
> > > + struct mt7531_mdio_priv *priv = dev_get_priv(dev);
> > > +
> > > + priv->switch_regs = dev_read_addr(dev);
> > > + if (priv->switch_regs == FDT_ADDR_T_NONE)
> > > + return -EINVAL;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +U_BOOT_DRIVER(mt7531_mdio) = {
> > > + .name = "mt7531-mdio",
> > > + .id = UCLASS_MDIO,
> > > + .probe = mt7531_mdio_probe,
> > > + .ops = &mt7531_mdio_ops,
> > > + .priv_auto = sizeof(struct mt7531_mdio_priv),
> > > +};
> > > diff --git a/drivers/net/mdio-mt7531.h b/drivers/net/mdio-mt7531.h
> > > new file mode 100644
> > > index 00000000000..ee096112f92
> > > --- /dev/null
> > > +++ b/drivers/net/mdio-mt7531.h
> > > @@ -0,0 +1,9 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +
> > > +struct mt7531_mdio_priv {
> > > + phys_addr_t switch_regs;
> > > +};
> > > +
> > > +int mt7531_mdio_read(struct udevice *dev, int addr, int devad, int
> > > reg);
> > > +int mt7531_mdio_write(struct udevice *dev, int addr, int devad,
> > > + int reg, u16 value);
> > > diff --git a/drivers/net/mtk_eth/Kconfig
> > > b/drivers/net/mtk_eth/Kconfig
> > > index e8cdf408237..67b2b612b1a 100644
> > > --- a/drivers/net/mtk_eth/Kconfig
> > > +++ b/drivers/net/mtk_eth/Kconfig
> > > @@ -4,6 +4,7 @@ config MEDIATEK_ETH
> > > select PHYLIB
> > > select DM_GPIO
> > > select DM_RESET
> > > + select MDIO_MT7531
> > > help
> > > This Driver support MediaTek Ethernet GMAC
> > > Say Y to enable support for the MediaTek Ethernet GMAC.
> > > diff --git a/drivers/net/mtk_eth/mt753x.c
> > > b/drivers/net/mtk_eth/mt753x.c
> > > index cdd52f3ff1b..cf643f336d6 100644
> > > --- a/drivers/net/mtk_eth/mt753x.c
> > > +++ b/drivers/net/mtk_eth/mt753x.c
> > > @@ -138,8 +138,8 @@ int mt7531_mii_read(struct mt753x_switch_priv
> > > *priv, u8 phy, u8 reg)
> > >
> > > phy_addr = MT753X_PHY_ADDR(priv->phy_base, phy);
> > >
> > > - return mt7531_mii_rw(priv, phy_addr, reg, 0, MDIO_CMD_READ,
> > > - MDIO_ST_C22);
> > > + return mt7531_mdio_read(&priv->mdio_priv, phy_addr,
> > > MDIO_DEVAD_NONE,
> > > + reg);
> > > }
> > >
> > > int mt7531_mii_write(struct mt753x_switch_priv *priv, u8 phy, u8
> > > reg, u16 val)
> > > @@ -151,48 +151,36 @@ int mt7531_mii_write(struct
> > > mt753x_switch_priv *priv, u8 phy, u8 reg, u16 val)
> > >
> > > phy_addr = MT753X_PHY_ADDR(priv->phy_base, phy);
> > >
> > > - return mt7531_mii_rw(priv, phy_addr, reg, val,
> > > MDIO_CMD_WRITE,
> > > - MDIO_ST_C22);
> > > + return mt7531_mdio_write(&priv->mdio_priv, phy_addr,
> > > MDIO_DEVAD_NONE,
> > > + reg, val);
> > > }
> > >
> > > int mt7531_mmd_read(struct mt753x_switch_priv *priv, u8 addr, u8
> > > devad,
> > > u16 reg)
> > > {
> > > u8 phy_addr;
> > > - int ret;
> > >
> > > if (addr >= MT753X_NUM_PHYS)
> > > return -EINVAL;
> > >
> > > phy_addr = MT753X_PHY_ADDR(priv->phy_base, addr);
> > >
> > > - ret = mt7531_mii_rw(priv, phy_addr, devad, reg,
> > > MDIO_CMD_ADDR,
> > > - MDIO_ST_C45);
> > > - if (ret)
> > > - return ret;
> > > -
> > > - return mt7531_mii_rw(priv, phy_addr, devad, 0,
> > > MDIO_CMD_READ_C45,
> > > - MDIO_ST_C45);
> > > + return mt7531_mdio_read(&priv->mdio_priv, phy_addr, devad,
> > > + reg);
> > > }
> > >
> > > int mt7531_mmd_write(struct mt753x_switch_priv *priv, u8 addr, u8
> > > devad,
> > > u16 reg, u16 val)
> > > {
> > > u8 phy_addr;
> > > - int ret;
> > >
> > > if (addr >= MT753X_NUM_PHYS)
> > > return 0;
> > >
> > > phy_addr = MT753X_PHY_ADDR(priv->phy_base, addr);
> > >
> > > - ret = mt7531_mii_rw(priv, phy_addr, devad, reg,
> > > MDIO_CMD_ADDR,
> > > - MDIO_ST_C45);
> > > - if (ret)
> > > - return ret;
> > > -
> > > - return mt7531_mii_rw(priv, phy_addr, devad, val,
> > > MDIO_CMD_WRITE,
> > > - MDIO_ST_C45);
> > > + return mt7531_mdio_write(&priv->mdio_priv, phy_addr, devad,
> > > + reg, val);
> > > }
> > >
> > > static int mt7531_mdio_read(struct mii_dev *bus, int addr, int
> > > devad, int reg)
> > > @@ -224,6 +212,7 @@ int mt7531_mdio_register(struct
> > > mt753x_switch_priv *priv)
> > > if (!mdio_bus)
> > > return -ENOMEM;
> > >
> > > + priv->mdio_priv.switch_regs = priv->epriv.ethsys_base +
> > > GSW_BASE;
>
> This will break all other platforms using dedicated MT7531 IC.
>
> Only mt7988 uses built-in mt7531 which allows memory-mapped register
> access. Other platforms connects mt7531 through MDIO bus and only
> supports accessing registers with MDIO.
>
> You should either change only mt7988 to use this logic, or modify the
> mdio-mt7531 to accept MDIO-based access.
>
Thanks for the feedback.
I can rework the MDIO driver to regmap and use that or limit it only to
mt7988. What do you prefer?
I think limiting to mt7988 is easier?
> > > mdio_bus->read = mt7531_mdio_read;
> > > mdio_bus->write = mt7531_mdio_write;
> > > snprintf(mdio_bus->name, sizeof(mdio_bus->name), priv-
> > > >epriv.sw->name);
> > > diff --git a/drivers/net/mtk_eth/mt753x.h
> > > b/drivers/net/mtk_eth/mt753x.h
> > > index 65046a1421c..cd128ad39fe 100644
> > > --- a/drivers/net/mtk_eth/mt753x.h
> > > +++ b/drivers/net/mtk_eth/mt753x.h
> > > @@ -14,6 +14,8 @@
> > > #include <linux/bitops.h>
> > > #include <linux/bitfield.h>
> > >
> > > +#include "../mdio-mt7531.h"
> > > +
> > > struct mtk_eth_priv;
> > >
> > > #define MT753X_NUM_PHYS 5
> > > @@ -254,6 +256,7 @@ struct mtk_eth_priv;
> > >
> > > struct mt753x_switch_priv {
> > > struct mtk_eth_switch_priv epriv;
> > > + struct mt7531_mdio_priv mdio_priv;
> > > struct mii_dev *mdio_bus;
> > > u32 smi_addr;
> > > u32 phy_base;
> > > --
> > > 2.50.0
> > >
> >
> > --
> > Ansuel
--
Ansuel
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