net: phy: added the LAN937x phy support

LAN937x T1 switch is based on LAN87xx Phy, so reusing the init script of
the LAN87xx. There is a workaround in accessing the DSP bank register
for LAN937x Phy. Whenever there is a bank switch to DSP registers, then
we need a one dummy read access before proceeding to the actual register
access.

Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/microchip_t1.c b/drivers/net/phy/microchip_t1.c
index d0bc012..6a7836c 100644 (file)
--- a/drivers/net/phy/microchip_t1.c
+++ b/drivers/net/phy/microchip_t1.c
@@ -8,13 +8,17 @@
 #include <linux/phy.h>
 #include <linux/ethtool.h>
 #include <linux/ethtool_netlink.h>
+#include <linux/bitfield.h>
 
 #define PHY_ID_LAN87XX                         0x0007c150
+#define PHY_ID_LAN937X                         0x0007c180
 
 /* External Register Control Register */
 #define LAN87XX_EXT_REG_CTL                     (0x14)
 #define LAN87XX_EXT_REG_CTL_RD_CTL              (0x1000)
 #define LAN87XX_EXT_REG_CTL_WR_CTL              (0x0800)
+#define LAN87XX_REG_BANK_SEL_MASK              GENMASK(10, 8)
+#define LAN87XX_REG_ADDR_MASK                  GENMASK(7, 0)
 
 /* External Register Read Data Register */
 #define LAN87XX_EXT_REG_RD_DATA                 (0x15)
@@ -76,7 +80,7 @@
 #define T1_PST_EQ_LCK_STG1_FRZ_CFG     0x6E
 
 #define DRIVER_AUTHOR  "Nisar Sayed <nisar.sayed@microchip.com>"
-#define DRIVER_DESC    "Microchip LAN87XX T1 PHY driver"
+#define DRIVER_DESC    "Microchip LAN87XX/LAN937x T1 PHY driver"
 
 struct access_ereg_val {
        u8  mode;
@@ -86,6 +90,37 @@ struct access_ereg_val {
        u16 mask;
 };
 
+static int lan937x_dsp_workaround(struct phy_device *phydev, u16 ereg, u8 bank)
+{
+       u8 prev_bank;
+       int rc = 0;
+       u16 val;
+
+       mutex_lock(&phydev->lock);
+       /* Read previous selected bank */
+       rc = phy_read(phydev, LAN87XX_EXT_REG_CTL);
+       if (rc < 0)
+               goto out_unlock;
+
+       /* store the prev_bank */
+       prev_bank = FIELD_GET(LAN87XX_REG_BANK_SEL_MASK, rc);
+
+       if (bank != prev_bank && bank == PHYACC_ATTR_BANK_DSP) {
+               val = ereg & ~LAN87XX_REG_ADDR_MASK;
+
+               val &= ~LAN87XX_EXT_REG_CTL_WR_CTL;
+               val |= LAN87XX_EXT_REG_CTL_RD_CTL;
+
+               /* access twice for DSP bank change,dummy access */
+               rc = phy_write(phydev, LAN87XX_EXT_REG_CTL, val);
+       }
+
+out_unlock:
+       mutex_unlock(&phydev->lock);
+
+       return rc;
+}
+
 static int access_ereg(struct phy_device *phydev, u8 mode, u8 bank,
                       u8 offset, u16 val)
 {
@@ -114,6 +149,13 @@ static int access_ereg(struct phy_device *phydev, u8 mode, u8 bank,
 
        ereg |= (bank << 8) | offset;
 
+       /* DSP bank access workaround for lan937x */
+       if (phydev->phy_id == PHY_ID_LAN937X) {
+               rc = lan937x_dsp_workaround(phydev, ereg, bank);
+               if (rc < 0)
+                       return rc;
+       }
+
        rc = phy_write(phydev, LAN87XX_EXT_REG_CTL, ereg);
        if (rc < 0)
                return rc;
@@ -642,6 +684,16 @@ static struct phy_driver microchip_t1_phy_driver[] = {
                .resume         = genphy_resume,
                .cable_test_start = lan87xx_cable_test_start,
                .cable_test_get_status = lan87xx_cable_test_get_status,
+       },
+       {
+               PHY_ID_MATCH_MODEL(PHY_ID_LAN937X),
+               .name           = "Microchip LAN937x T1",
+               .features       = PHY_BASIC_T1_FEATURES,
+               .config_init    = lan87xx_config_init,
+               .suspend        = genphy_suspend,
+               .resume         = genphy_resume,
+               .cable_test_start = lan87xx_cable_test_start,
+               .cable_test_get_status = lan87xx_cable_test_get_status,
        }
 };
 
@@ -649,6 +701,7 @@ module_phy_driver(microchip_t1_phy_driver);
 
 static struct mdio_device_id __maybe_unused microchip_t1_tbl[] = {
        { PHY_ID_MATCH_MODEL(PHY_ID_LAN87XX) },
+       { PHY_ID_MATCH_MODEL(PHY_ID_LAN937X) },
        { }
 };