net: ethernet: gianfar_ethtool: get phc index through drvdata

Global variable gfar_phc_index was used to get and store
phc index through gianfar_ptp driver. However gianfar_ptp
had been renamed as ptp_qoriq for QorIQ common PTP driver.
This gfar_phc_index doesn't work any more, and the phc index
is stored in drvdata now. This patch is to support getting
phc index through ptp_qoriq drvdata.

Signed-off-by: Yangbo Lu <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/freescale/gianfar.h

···
 	struct gfar_filer_entry fe[MAX_FILER_CACHE_IDX + 20];
 };
 
-/* The gianfar_ptp module will set this variable */
-extern int gfar_phc_index;
-
 #endif /* __GIANFAR_H */

drivers/net/ethernet/freescale/gianfar_ethtool.c

···
 #include <linux/phy.h>
 #include <linux/sort.h>
 #include <linux/if_vlan.h>
+#include <linux/of_platform.h>
+#include <linux/fsl/ptp_qoriq.h>
 
 #include "gianfar.h"
 
···
 	return ret;
 }
 
-int gfar_phc_index = -1;
-EXPORT_SYMBOL(gfar_phc_index);
-
 static int gfar_get_ts_info(struct net_device *dev,
 			    struct ethtool_ts_info *info)
 {
 	struct gfar_private *priv = netdev_priv(dev);
+	struct platform_device *ptp_dev;
+	struct device_node *ptp_node;
+	struct qoriq_ptp *ptp = NULL;
+
+	info->phc_index = -1;
 
 	if (!(priv->device_flags & FSL_GIANFAR_DEV_HAS_TIMER)) {
 		info->so_timestamping = SOF_TIMESTAMPING_RX_SOFTWARE |
 					SOF_TIMESTAMPING_SOFTWARE;
-		info->phc_index = -1;
 		return 0;
 	}
+
+	ptp_node = of_find_compatible_node(NULL, NULL, "fsl,etsec-ptp");
+	if (ptp_node) {
+		ptp_dev = of_find_device_by_node(ptp_node);
+		if (ptp_dev)
+			ptp = platform_get_drvdata(ptp_dev);
+	}
+
+	if (ptp)
+		info->phc_index = ptp->phc_index;
+
 	info->so_timestamping = SOF_TIMESTAMPING_TX_HARDWARE |
 				SOF_TIMESTAMPING_RX_HARDWARE |
 				SOF_TIMESTAMPING_RAW_HARDWARE;
-	info->phc_index = gfar_phc_index;
 	info->tx_types = (1 << HWTSTAMP_TX_OFF) |
 			 (1 << HWTSTAMP_TX_ON);
 	info->rx_filters = (1 << HWTSTAMP_FILTER_NONE) |