[RFC PATCH v1 5/9] net: phy: micrel: ksz886x add MDI-X support

Oleksij Rempel
2021-05-05T09:22:23Z

Add support for MDI-X status and configuration

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
drivers/net/phy/micrel.c | 101 +++++++++++++++++++++++++++++++++++++++
1 file changed, 101 insertions(+)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index f03188ed953a..ea30cd6bd7bc 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -28,6 +28,19 @@
#include <linux/clk.h>
#include <linux/delay.h>

+/* Device specific MII_BMCR (Reg 0) bits */
+/* 1 = HP Auto MDI/MDI-X mode, 0 = Microchip Auto MDI/MDI-X mode */
+#define KSZ886X_BMCR_HP_MDIX BIT(5)
+/* 1 = Force MDI (transmit on RXP/RXM pins), 0 = Normal operation
+ * (transmit on TXP/TXM pins)
+ */
+#define KSZ886X_BMCR_FORCE_MDI BIT(4)
+/* 1 = Disable auto MDI-X */
+#define KSZ886X_BMCR_DISABLE_AUTO_MDIX BIT(3)
+#define KSZ886X_BMCR_DISABLE_FAR_END_FAULT BIT(2)
+#define KSZ886X_BMCR_DISABLE_TRANSMIT BIT(1)
+#define KSZ886X_BMCR_DISABLE_LED BIT(0)
+
/* Operation Mode Strap Override */
#define MII_KSZPHY_OMSO 0x16
#define KSZPHY_OMSO_FACTORY_TEST BIT(15)
@@ -62,6 +75,7 @@
/* bitmap of PHY register to set interrupt mode */
#define KSZPHY_CTRL_INT_ACTIVE_HIGH BIT(9)
#define KSZPHY_RMII_REF_CLK_SEL BIT(7)
+#define KSZ886X_CTRL_MDIX_STAT BIT(4)

/* Write/read to/from extended registers */
#define MII_KSZPHY_EXTREG 0x0b
@@ -1048,6 +1062,91 @@ static int ksz8873mll_config_aneg(struct phy_device *phydev)
return 0;
}

+static int ksz886x_config_mdix(struct phy_device *phydev, u8 ctrl)
+{
+ u16 val;
+
+ switch (ctrl) {
+ case ETH_TP_MDI:
+ val = KSZ886X_BMCR_DISABLE_AUTO_MDIX;
+ break;
+ case ETH_TP_MDI_X:
+ /* Note: The naming of the bit KSZ886X_BMCR_FORCE_MDI is bit
+ * counter intuitive, the "-X" in "1 = Force MDI" in the data
+ * sheet seems to be missing:
+ * 1 = Force MDI (sic!) (transmit on RX+/RX- pins)
+ * 0 = Normal operation (transmit on TX+/TX- pins)
+ */
+ val = KSZ886X_BMCR_DISABLE_AUTO_MDIX | KSZ886X_BMCR_FORCE_MDI;
+ break;
+ case ETH_TP_MDI_AUTO:
+ val = 0;
+ break;
+ default:
+ return 0;
+ }
+
+ return phy_modify(phydev, MII_BMCR,
+ KSZ886X_BMCR_HP_MDIX | KSZ886X_BMCR_FORCE_MDI |
+ KSZ886X_BMCR_DISABLE_AUTO_MDIX,
+ KSZ886X_BMCR_HP_MDIX | val);
+}
+
+static int ksz886x_config_aneg(struct phy_device *phydev)
+{
+ int ret;
+
+ ret = genphy_config_aneg(phydev);
+ if (ret)
+ return ret;
+
+ /* The MDI-X configuration is automatically changed by the PHY after
+ * switching from autoneg off to on. So, take MDI-X configuration under
+ * own control and set it after autoneg configuration was done.
+ */
+ return ksz886x_config_mdix(phydev, phydev->mdix_ctrl);
+}
+
+static int ksz886x_mdix_update(struct phy_device *phydev)
+{
+ int ret;
+
+ ret = phy_read(phydev, MII_BMCR);
+ if (ret < 0)
+ return ret;
+
+ if (ret & KSZ886X_BMCR_DISABLE_AUTO_MDIX) {
+ if (ret & KSZ886X_BMCR_FORCE_MDI)
+ phydev->mdix_ctrl = ETH_TP_MDI_X;
+ else
+ phydev->mdix_ctrl = ETH_TP_MDI;
+ } else {
+ phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
+ }
+
+ ret = phy_read(phydev, MII_KSZPHY_CTRL);
+ if (ret < 0)
+ return ret;
+
+ if (ret & KSZ886X_CTRL_MDIX_STAT)
+ phydev->mdix = ETH_TP_MDI;
+ else
+ phydev->mdix = ETH_TP_MDI_X;
+
+ return 0;
+}
+
+static int ksz886x_read_status(struct phy_device *phydev)
+{
+ int ret;
+
+ ret = ksz886x_mdix_update(phydev);
+ if (ret < 0)
+ return ret;
+
+ return genphy_read_status(phydev);
+}
+
static int ksz886x_resume(struct phy_device *phydev)
{
int ret;
@@ -1420,6 +1519,8 @@ static struct phy_driver ksphy_driver[] = {
.name = "Micrel KSZ8851 Ethernet MAC or KSZ886X Switch",
/* PHY_BASIC_FEATURES */
.config_init = kszphy_config_init,
+ .config_aneg = ksz886x_config_aneg,
+ .read_status = ksz886x_read_status,
.suspend = genphy_suspend,
.resume = ksz886x_resume,
}, {
--
2.29.2