[PATCH net-next v4 1/1] net: phy: dp83td510: add SQI support

From: Oleksij Rempel
Date: Mon Jun 20 2022 - 07:56:17 EST


Convert MSE (mean-square error) values to SNR and split it SQI (Signal Quality
Indicator) ranges. The used ranges are taken from "OPEN ALLIANCE - Advanced
diagnostic features for 100BASE-T1 automotive Ethernet PHYs"
specification.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
---
drivers/net/phy/dp83td510.c | 49 +++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)

diff --git a/drivers/net/phy/dp83td510.c b/drivers/net/phy/dp83td510.c
index 1ae792b0daaa..3cd9a77f9532 100644
--- a/drivers/net/phy/dp83td510.c
+++ b/drivers/net/phy/dp83td510.c
@@ -27,6 +27,27 @@
#define DP83TD510E_AN_STAT_1 0x60c
#define DP83TD510E_MASTER_SLAVE_RESOL_FAIL BIT(15)

+#define DP83TD510E_MSE_DETECT 0xa85
+
+#define DP83TD510_SQI_MAX 7
+
+/* Register values are converted to SNR(dB) as suggested by
+ * "Application Report - DP83TD510E Cable Diagnostics Toolkit":
+ * SNR(dB) = -10 * log10 (VAL/2^17) - 1.76 dB.
+ * SQI ranges are implemented according to "OPEN ALLIANCE - Advanced diagnostic
+ * features for 100BASE-T1 automotive Ethernet PHYs"
+ */
+static const u16 dp83td510_mse_sqi_map[] = {
+ 0x0569, /* < 18dB */
+ 0x044c, /* 18dB =< SNR < 19dB */
+ 0x0369, /* 19dB =< SNR < 20dB */
+ 0x02b6, /* 20dB =< SNR < 21dB */
+ 0x0227, /* 21dB =< SNR < 22dB */
+ 0x01b6, /* 22dB =< SNR < 23dB */
+ 0x015b, /* 23dB =< SNR < 24dB */
+ 0x0000 /* 24dB =< SNR */
+};
+
static int dp83td510_config_intr(struct phy_device *phydev)
{
int ret;
@@ -164,6 +185,32 @@ static int dp83td510_config_aneg(struct phy_device *phydev)
return genphy_c45_check_and_restart_aneg(phydev, changed);
}

+static int dp83td510_get_sqi(struct phy_device *phydev)
+{
+ int sqi, ret;
+ u16 mse_val;
+
+ if (!phydev->link)
+ return 0;
+
+ ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, DP83TD510E_MSE_DETECT);
+ if (ret < 0)
+ return ret;
+
+ mse_val = 0xFFFF & ret;
+ for (sqi = 0; sqi < ARRAY_SIZE(dp83td510_mse_sqi_map); sqi++) {
+ if (mse_val >= dp83td510_mse_sqi_map[sqi])
+ return sqi;
+ }
+
+ return -EINVAL;
+}
+
+static int dp83td510_get_sqi_max(struct phy_device *phydev)
+{
+ return DP83TD510_SQI_MAX;
+}
+
static int dp83td510_get_features(struct phy_device *phydev)
{
/* This PHY can't respond on MDIO bus if no RMII clock is enabled.
@@ -192,6 +239,8 @@ static struct phy_driver dp83td510_driver[] = {
.get_features = dp83td510_get_features,
.config_intr = dp83td510_config_intr,
.handle_interrupt = dp83td510_handle_interrupt,
+ .get_sqi = dp83td510_get_sqi,
+ .get_sqi_max = dp83td510_get_sqi_max,

.suspend = genphy_suspend,
.resume = genphy_resume,
--
2.30.2