ptp: add kernel API ptp_get_vclocks_index()

Add kernel API ptp_get_vclocks_index() to get all ptp
vclocks index on pclock.

This is preparation for supporting ptp vclocks info query
through ethtool.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/ptp/ptp_vclock.c b/drivers/ptp/ptp_vclock.c
index fc9205cc504d..cefab29a0592 100644
--- a/drivers/ptp/ptp_vclock.c
+++ b/drivers/ptp/ptp_vclock.c
@@ -148,3 +148,38 @@ void ptp_vclock_unregister(struct ptp_vclock *vclock)
 	ptp_clock_unregister(vclock->clock);
 	kfree(vclock);
 }
+
+int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
+{
+	char name[PTP_CLOCK_NAME_LEN] = "";
+	struct ptp_clock *ptp;
+	struct device *dev;
+	int num = 0;
+
+	if (pclock_index < 0)
+		return num;
+
+	snprintf(name, PTP_CLOCK_NAME_LEN, "ptp%d", pclock_index);
+	dev = class_find_device_by_name(ptp_class, name);
+	if (!dev)
+		return num;
+
+	ptp = dev_get_drvdata(dev);
+
+	if (mutex_lock_interruptible(&ptp->n_vclocks_mux)) {
+		put_device(dev);
+		return num;
+	}
+
+	*vclock_index = kzalloc(sizeof(int) * ptp->n_vclocks, GFP_KERNEL);
+	if (!(*vclock_index))
+		goto out;
+
+	memcpy(*vclock_index, ptp->vclock_index, sizeof(int) * ptp->n_vclocks);
+	num = ptp->n_vclocks;
+out:
+	mutex_unlock(&ptp->n_vclocks_mux);
+	put_device(dev);
+	return num;
+}
+EXPORT_SYMBOL(ptp_get_vclocks_index);