[PATCH net-next v3 2/3] phy: mscc: Add support for RGMII delay configuration

[Harini Katakam <harini.katakam@amd.com>]

Add support for optional rx/tx-internal-delay-ps from devicetree.
- When rx/tx-internal-delay-ps is/are specified, these take priority
- When either is absent,
1) use 2ns for respective settings if rgmii-id/rxid/txid is/are present
2) use 0.2ns for respective settings if mode is rgmii

Signed-off-by: Harini Katakam <harini.katakam@amd.com>
---
v3 - Patch split:
- Use rx/tx-internal-delay-ps with phy_get_internal_delay
- Change RGMII delay selection precedence
- Update commit description and subject everywhere to say RGMII delays
instead of RGMII tuning.

 drivers/net/phy/mscc/mscc.h      |  2 ++
 drivers/net/phy/mscc/mscc_main.c | 35 +++++++++++++++++++++++++-------
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/drivers/net/phy/mscc/mscc.h b/drivers/net/phy/mscc/mscc.h
index 9acee8759105..ab6c0b7c2136 100644
--- a/drivers/net/phy/mscc/mscc.h
+++ b/drivers/net/phy/mscc/mscc.h
@@ -374,6 +374,8 @@ struct vsc8531_private {
 	 * package.
 	 */
 	unsigned int base_addr;
+	u32 rx_delay;
+	u32 tx_delay;
 
 #if IS_ENABLED(CONFIG_MACSEC)
 	/* MACsec fields:
diff --git a/drivers/net/phy/mscc/mscc_main.c b/drivers/net/phy/mscc/mscc_main.c
index 91010524e03d..9e856231e464 100644
--- a/drivers/net/phy/mscc/mscc_main.c
+++ b/drivers/net/phy/mscc/mscc_main.c
@@ -525,17 +525,14 @@ static int vsc85xx_rgmii_set_skews(struct phy_device *phydev, u32 rgmii_cntl,
 {
 	u16 rgmii_rx_delay_pos = ffs(rgmii_rx_delay_mask) - 1;
 	u16 rgmii_tx_delay_pos = ffs(rgmii_tx_delay_mask) - 1;
+	struct vsc8531_private *vsc8531 = phydev->priv;
 	u16 reg_val = 0;
 	int rc;
 
 	mutex_lock(&phydev->lock);
 
-	if (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID ||
-	    phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
-		reg_val |= RGMII_CLK_DELAY_2_0_NS << rgmii_rx_delay_pos;
-	if (phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID ||
-	    phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
-		reg_val |= RGMII_CLK_DELAY_2_0_NS << rgmii_tx_delay_pos;
+	reg_val |= vsc8531->rx_delay << rgmii_rx_delay_pos;
+	reg_val |= vsc8531->tx_delay << rgmii_tx_delay_pos;
 
 	rc = phy_modify_paged(phydev, MSCC_PHY_PAGE_EXTENDED_2,
 			      rgmii_cntl,
@@ -1808,10 +1805,34 @@ static irqreturn_t vsc8584_handle_interrupt(struct phy_device *phydev)
 	return IRQ_HANDLED;
 }
 
+static const int vsc8531_internal_delay[] = {200, 800, 1100, 1700, 2000, 2300,
+					     2600, 3400};
 static int vsc85xx_config_init(struct phy_device *phydev)
 {
-	int rc, i, phy_id;
+	int delay_size = ARRAY_SIZE(vsc8531_internal_delay);
 	struct vsc8531_private *vsc8531 = phydev->priv;
+	struct device *dev = &phydev->mdio.dev;
+	int rc, i, phy_id;
+
+	vsc8531->rx_delay = phy_get_internal_delay(phydev, dev, &vsc8531_internal_delay[0],
+						   delay_size, true);
+	if (vsc8531->rx_delay < 0) {
+		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID ||
+		    phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
+			vsc8531->rx_delay = RGMII_CLK_DELAY_2_0_NS;
+		else
+			vsc8531->rx_delay = RGMII_CLK_DELAY_0_2_NS;
+	}
+
+	vsc8531->tx_delay = phy_get_internal_delay(phydev, dev, &vsc8531_internal_delay[0],
+						   delay_size, false);
+	if (vsc8531->tx_delay < 0) {
+		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID ||
+		    phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
+			vsc8531->rx_delay = RGMII_CLK_DELAY_2_0_NS;
+		else
+			vsc8531->rx_delay = RGMII_CLK_DELAY_0_2_NS;
+	}
 
 	rc = vsc85xx_default_config(phydev);
 	if (rc)
-- 
2.17.1