Merge branch 'net-stmmac-fix-tegra234-mgbe-clock'

Jon Hunter says:

====================
net: stmmac: Fix Tegra234 MGBE clock

The name of the PTP ref clock for the Tegra234 MGBE ethernet controller
does not match the generic name in the stmmac platform driver. Despite
this basic ethernet is functional on the Tegra234 platforms that use
this driver and as far as I know, we have not tested PTP support with
this driver. Hence, the risk of breaking any functionality is low.

The previous attempt to fix this in the stmmac platform driver, by
supporting the Tegra234 PTP clock name, was rejected [0]. The preference
from the netdev maintainers is to fix this in the DT binding for
Tegra234.

This series fixes this by correcting the device-tree binding to align
with the generic name for the PTP clock. I understand that this is
breaking the ABI for this device, which we should never do, but this
is a last resort for getting this fixed. I am open to any better ideas
to fix this. Please note that we still maintain backward compatibility
in the driver to allow older device-trees to work, but we don't
advertise this via the binding, because I did not see any value in doing
so.
====================

Link: https://patch.msgid.link/20260401102941.17466-1-jonathanh@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 19 insertions, 4 deletions

diff --git a/Documentation/devicetree/bindings/net/nvidia,tegra234-mgbe.yaml b/Documentation/devicetree/bindings/net/nvidia,tegra234-mgbe.yaml
index 2bd3efff2485..215f14d1897d 100644
--- a/Documentation/devicetree/bindings/net/nvidia,tegra234-mgbe.yaml
+++ b/Documentation/devicetree/bindings/net/nvidia,tegra234-mgbe.yaml
@@ -42,7 +42,7 @@ properties:
       - const: mgbe
       - const: mac
       - const: mac-divider
-      - const: ptp-ref
+      - const: ptp_ref
       - const: rx-input-m
       - const: rx-input
       - const: tx
@@ -133,7 +133,7 @@ examples:
                  <&bpmp TEGRA234_CLK_MGBE0_RX_PCS_M>,
                  <&bpmp TEGRA234_CLK_MGBE0_RX_PCS>,
                  <&bpmp TEGRA234_CLK_MGBE0_TX_PCS>;
-        clock-names = "mgbe", "mac", "mac-divider", "ptp-ref", "rx-input-m",
+        clock-names = "mgbe", "mac", "mac-divider", "ptp_ref", "rx-input-m",
                       "rx-input", "tx", "eee-pcs", "rx-pcs-input", "rx-pcs-m",
                       "rx-pcs", "tx-pcs";
         resets = <&bpmp TEGRA234_RESET_MGBE0_MAC>,
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c
index d765acbe3754..21a0a11fc011 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c
@@ -9,7 +9,7 @@
 #include "stmmac_platform.h"
 
 static const char *const mgbe_clks[] = {
-	"rx-pcs", "tx", "tx-pcs", "mac-divider", "mac", "mgbe", "ptp-ref", "mac"
+	"rx-pcs", "tx", "tx-pcs", "mac-divider", "mac", "mgbe", "ptp_ref", "mac"
 };
 
 struct tegra_mgbe {
@@ -215,6 +215,7 @@ static int tegra_mgbe_probe(struct platform_device *pdev)
 {
 	struct plat_stmmacenet_data *plat;
 	struct stmmac_resources res;
+	bool use_legacy_ptp = false;
 	struct tegra_mgbe *mgbe;
 	int irq, err, i;
 	u32 value;
@@ -257,9 +258,23 @@ static int tegra_mgbe_probe(struct platform_device *pdev)
 	if (!mgbe->clks)
 		return -ENOMEM;
 
-	for (i = 0; i <  ARRAY_SIZE(mgbe_clks); i++)
+	/* Older device-trees use 'ptp-ref' rather than 'ptp_ref'.
+	 * Fall back when the legacy name is present.
+	 */
+	if (of_property_match_string(pdev->dev.of_node, "clock-names",
+				     "ptp-ref") >= 0)
+		use_legacy_ptp = true;
+
+	for (i = 0; i < ARRAY_SIZE(mgbe_clks); i++) {
 		mgbe->clks[i].id = mgbe_clks[i];
 
+		if (use_legacy_ptp && !strcmp(mgbe_clks[i], "ptp_ref")) {
+			dev_warn(mgbe->dev,
+				 "Device-tree update needed for PTP clock!\n");
+			mgbe->clks[i].id = "ptp-ref";
+		}
+	}
+
 	err = devm_clk_bulk_get(mgbe->dev, ARRAY_SIZE(mgbe_clks), mgbe->clks);
 	if (err < 0)
 		return err;