Re: [RFC PATCH 3/9] net: dsa: hellcreek: Add PTP clock support

Hi Richard,

On Wed Jun 24 2020, Richard Cochran wrote:

On Thu, Jun 18, 2020 at 08:40:23AM +0200, Kurt Kanzenbach wrote:

quoted

diff --git a/drivers/net/dsa/hirschmann/hellcreek.h b/drivers/net/dsa/hirschmann/hellcreek.h
index a08a10cb5ab7..2d4422fd2567 100644
--- a/drivers/net/dsa/hirschmann/hellcreek.h
+++ b/drivers/net/dsa/hirschmann/hellcreek.h

@@ -234,10 +234,17 @@ struct hellcreek_fdb_entry {
 struct hellcreek {
 	struct device *dev;
 	struct dsa_switch *ds;
+	struct ptp_clock *ptp_clock;
+	struct ptp_clock_info ptp_clock_info;
 	struct hellcreek_port ports[4];
+	struct delayed_work overflow_work;
 	spinlock_t reg_lock;	/* Switch IP register lock */
+	spinlock_t ptp_lock;	/* PTP IP register lock */

Why use a spin lock and not a mutex?

No particular reason. Mutex will also work.

quoted

+	hellcreek->ptp_clock = ptp_clock_register(&hellcreek->ptp_clock_info,
+						  hellcreek->dev);
+	if (IS_ERR(hellcreek->ptp_clock))
+		return PTR_ERR(hellcreek->ptp_clock);

The ptp_clock_register() can also return NULL:

 * Returns a valid pointer on success or PTR_ERR on failure.  If PHC
 * support is missing at the configuration level, this function
 * returns NULL, and drivers are expected to gracefully handle that
 * case separately.

I see, thanks. I guess we could add the missing NULL checks to remove()
and get_ts_info() to handle that case gracefully.

Thanks,
Kurt