ravb: Use separate clock for gPTP

RZ/V2M has a separate gPTP reference clock that is used when the
AVB-DMAC Mode Register (CCC) gPTP Clock Select (CSEL) bits are
set to "01: High-speed peripheral bus clock".
Therefore, add a feature that allows this clock to be used for
gPTP.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/ravb.h

@@ -1031,6 +1031,7 @@ struct ravb_hw_info {
 	unsigned err_mgmt_irqs:1;	/* Line1 (Err) and Line2 (Mgmt) irqs are separate */
 	unsigned gptp:1;		/* AVB-DMAC has gPTP support */
 	unsigned ccc_gac:1;		/* AVB-DMAC has gPTP support active in config mode */
+	unsigned gptp_ref_clk:1;	/* gPTP has separate reference clock */
 	unsigned nc_queues:1;		/* AVB-DMAC has RX and TX NC queues */
 	unsigned magic_pkt:1;		/* E-MAC supports magic packet detection */
 	unsigned half_duplex:1;		/* E-MAC supports half duplex mode */
@@ -1042,6 +1043,7 @@ struct ravb_private {
 	void __iomem *addr;
 	struct clk *clk;
 	struct clk *refclk;
+	struct clk *gptp_clk;
 	struct mdiobb_ctrl mdiobb;
 	u32 num_rx_ring[NUM_RX_QUEUE];
 	u32 num_tx_ring[NUM_TX_QUEUE];

drivers/net/ethernet/renesas/ravb_main.c

@@ -2495,11 +2495,15 @@ MODULE_DEVICE_TABLE(of, ravb_match_table);
 static int ravb_set_gti(struct net_device *ndev)
 {
 	struct ravb_private *priv = netdev_priv(ndev);
+	const struct ravb_hw_info *info = priv->info;
 	struct device *dev = ndev->dev.parent;
 	unsigned long rate;
 	uint64_t inc;
 
-	rate = clk_get_rate(priv->clk);
+	if (info->gptp_ref_clk)
+		rate = clk_get_rate(priv->gptp_clk);
+	else
+		rate = clk_get_rate(priv->clk);
 	if (!rate)
 		return -EINVAL;
 
@@ -2721,6 +2725,15 @@ static int ravb_probe(struct platform_device *pdev)
 	}
 	clk_prepare_enable(priv->refclk);
 
+	if (info->gptp_ref_clk) {
+		priv->gptp_clk = devm_clk_get(&pdev->dev, "gptp");
+		if (IS_ERR(priv->gptp_clk)) {
+			error = PTR_ERR(priv->gptp_clk);
+			goto out_disable_refclk;
+		}
+		clk_prepare_enable(priv->gptp_clk);
+	}
+
 	ndev->max_mtu = info->rx_max_buf_size - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
 	ndev->min_mtu = ETH_MIN_MTU;
 
@@ -2742,7 +2755,7 @@ static int ravb_probe(struct platform_device *pdev)
 		/* Set GTI value */
 		error = ravb_set_gti(ndev);
 		if (error)
-			goto out_disable_refclk;
+			goto out_disable_gptp_clk;
 
 		/* Request GTI loading */
 		ravb_modify(ndev, GCCR, GCCR_LTI, GCCR_LTI);
@@ -2762,7 +2775,7 @@ static int ravb_probe(struct platform_device *pdev)
 			"Cannot allocate desc base address table (size %d bytes)\n",
 			priv->desc_bat_size);
 		error = -ENOMEM;
-		goto out_disable_refclk;
+		goto out_disable_gptp_clk;
 	}
 	for (q = RAVB_BE; q < DBAT_ENTRY_NUM; q++)
 		priv->desc_bat[q].die_dt = DT_EOS;
@@ -2825,6 +2838,8 @@ static int ravb_probe(struct platform_device *pdev)
 	/* Stop PTP Clock driver */
 	if (info->ccc_gac)
 		ravb_ptp_stop(ndev);
+out_disable_gptp_clk:
+	clk_disable_unprepare(priv->gptp_clk);
 out_disable_refclk:
 	clk_disable_unprepare(priv->refclk);
 out_release:
@@ -2846,6 +2861,7 @@ static int ravb_remove(struct platform_device *pdev)
 	if (info->ccc_gac)
 		ravb_ptp_stop(ndev);
 
+	clk_disable_unprepare(priv->gptp_clk);
 	clk_disable_unprepare(priv->refclk);
 
 	dma_free_coherent(ndev->dev.parent, priv->desc_bat_size, priv->desc_bat,