[PATCH net-next v3 2/5] net: lan743x: read SFP straps from PCI11x1x device

[Thangaraj Samynathan <thangaraj.s@microchip.com>]

Reads the SFP enable bits from the strap registers to determine
if the hardware is configured for SFP usage.

- Add STRAP_SFP_USE_EN_ and STRAP_SFP_EN_ definitions to read SFP
straps.
- Store SFP status in the adapter's is_sfp_support_en flag.
- Add a validation check to ensure PCS is enabled when SFP support
is requested, as SFP operation requires the PCS interface.
- Refactor debug logging to use the str_enable_disable() helper for
  consistency with modern kernel standards.

Signed-off-by: Thangaraj Samynathan <thangaraj.s@microchip.com>
---
 drivers/net/ethernet/microchip/lan743x_main.c | 16 ++++++++++++++++
 drivers/net/ethernet/microchip/lan743x_main.h |  3 +++
 2 files changed, 19 insertions(+)

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index fad4a246e06e..867310dbe9ba 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -62,6 +62,12 @@ static void pci11x1x_strap_get_status(struct lan743x_adapter *adapter)
 			adapter->is_pcs_en = true;
 		else
 			adapter->is_pcs_en = false;
+
+		if ((strap & STRAP_SFP_USE_EN_) && (strap & STRAP_SFP_EN_))
+			adapter->is_sfp_support_en = true;
+		else
+			adapter->is_sfp_support_en = false;
+
 	} else {
 		fpga_rev = lan743x_csr_read(adapter, FPGA_REV);
 		if (fpga_rev) {
@@ -73,8 +79,17 @@ static void pci11x1x_strap_get_status(struct lan743x_adapter *adapter)
 			adapter->is_pcs_en = false;
 		}
 	}
+
+	if (adapter->is_pci11x1x && !adapter->is_pcs_en &&
+	    adapter->is_sfp_support_en) {
+		netif_err(adapter, drv, adapter->netdev,
+			  "Invalid EEPROM configuration: SFP_EN strap specified without SGMII_EN strap\n");
+	}
+
 	netif_dbg(adapter, drv, adapter->netdev,
 		  "PCS I/F %s\n", str_enable_disable(adapter->is_pcs_en));
+	netif_dbg(adapter, drv, adapter->netdev,
+		  "SFP support %s\n", str_enable_disable(adapter->is_sfp_support_en));
 }
 
 static bool is_pci11x1x_chip(struct lan743x_adapter *adapter)
@@ -3665,6 +3680,7 @@ static int lan743x_pcidev_probe(struct pci_dev *pdev,
 			      NETIF_MSG_LINK | NETIF_MSG_IFUP |
 			      NETIF_MSG_IFDOWN | NETIF_MSG_TX_QUEUED;
 	netdev->max_mtu = LAN743X_MAX_FRAME_SIZE;
+	adapter->is_sfp_support_en = false;
 
 	of_get_mac_address(pdev->dev.of_node, adapter->mac_address);
 
diff --git a/drivers/net/ethernet/microchip/lan743x_main.h b/drivers/net/ethernet/microchip/lan743x_main.h
index f0fa0580b04e..26c30dc2e55c 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.h
+++ b/drivers/net/ethernet/microchip/lan743x_main.h
@@ -37,6 +37,8 @@
 
 #define STRAP_READ			(0x0C)
 #define STRAP_READ_USE_SGMII_EN_	BIT(22)
+#define STRAP_SFP_USE_EN_              BIT(31)
+#define STRAP_SFP_EN_                  BIT(15)
 #define STRAP_READ_SGMII_EN_		BIT(6)
 #define STRAP_READ_SGMII_REFCLK_	BIT(5)
 #define STRAP_READ_SGMII_2_5G_		BIT(4)
@@ -1081,6 +1083,7 @@ struct lan743x_adapter {
 	u8			max_tx_channels;
 	u8			used_tx_channels;
 	u8			max_vector_count;
+	bool                    is_sfp_support_en;
 
 #define LAN743X_ADAPTER_FLAG_OTP		BIT(0)
 	u32			flags;
-- 
2.34.1