[PATCH 6.18 081/198] net: stmmac: Fix PTP ref clock for Tegra234

Greg Kroah-Hartman
2026-04-20T15:59:29Z

From: Jon Hunter <jonathanh@nvidia.com>

[ Upstream commit 1345e9f4e3f3bc7d8a0a2138ae29e205a857a555 ]

Since commit 030ce919e114 ("net: stmmac: make sure that ptp_rate is not
0 before configuring timestamping") was added the following error is
observed on Tegra234:

ERR KERN tegra-mgbe 6800000.ethernet eth0: Invalid PTP clock rate
WARNING KERN tegra-mgbe 6800000.ethernet eth0: PTP init failed

It turns out that the Tegra234 device-tree binding defines the PTP ref
clock name as 'ptp-ref' and not 'ptp_ref' and the above commit now
exposes this and that the PTP clock is not configured correctly.

In order to update device-tree to use the correct 'ptp_ref' name, update
the Tegra MGBE driver to use 'ptp_ref' by default and fallback to using
'ptp-ref' if this clock name is present.

Fixes: d8ca113724e7 ("net: stmmac: tegra: Add MGBE support")
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260401102941.17466-2-jonathanh@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../net/ethernet/stmicro/stmmac/dwmac-tegra.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c
index d765acbe37548..21a0a11fc0118 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;
--
2.53.0