[PATCH net-next 5/6] net: phy: added the LAN937x phy support

From: Arun Ramadoss
Date: Fri Mar 04 2022 - 04:45:22 EST


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@xxxxxxxxxxxxx>
Signed-off-by: Arun Ramadoss <arun.ramadoss@xxxxxxxxxxxxx>
---
drivers/net/phy/microchip_t1.c | 55 +++++++++++++++++++++++++++++++++-
1 file changed, 54 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/microchip_t1.c b/drivers/net/phy/microchip_t1.c
index d0bc0125f3ef..6a7836c2961a 100644
--- 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@xxxxxxxxxxxxx>"
-#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) },
{ }
};

--
2.33.0