@@ -280,7 +280,10 @@ void stmmac_ptp_register(struct stmmac_priv *priv)
priv->plat->cdc_error_adj = (2 * NSEC_PER_SEC) / priv->plat->clk_ptp_rate;
stmmac_ptp_clock_ops.n_per_out = priv->dma_cap.pps_out_num;
- stmmac_ptp_clock_ops.n_ext_ts = priv->dma_cap.aux_snapshot_n;
+ /* Number of available external triggers is not provided through a
+ * hardware capabilities register for GMAC3
+ */
+ stmmac_ptp_clock_ops.n_ext_ts = priv->plat->has_gmac ? 1 : priv->dma_cap.aux_snapshot_n;
rwlock_init(&priv->ptp_lock);
mutex_init(&priv->aux_ts_lock);