net: dsa: microchip: Add suspend/resume support to KSZ DSA driver

The KSZ DSA driver starts a timer to read MIB counters periodically to
avoid count overrun.  During system suspend this will give an error for
not able to write to register as the SPI system returns an error when
it is in suspend state.  This implementation stops the timer when the
system goes into suspend and restarts it when resumed.

Signed-off-by: Tristram Ha <tristram.ha@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20241218020311.70628-1-Tristram.Ha@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index df314724e6a7..a8dac7ff6b81 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -4586,6 +4586,23 @@ static int ksz_hsr_leave(struct dsa_switch *ds, int port,
 	return 0;
 }
 
+static int ksz_suspend(struct dsa_switch *ds)
+{
+	struct ksz_device *dev = ds->priv;
+
+	cancel_delayed_work_sync(&dev->mib_read);
+	return 0;
+}
+
+static int ksz_resume(struct dsa_switch *ds)
+{
+	struct ksz_device *dev = ds->priv;
+
+	if (dev->mib_read_interval)
+		schedule_delayed_work(&dev->mib_read, dev->mib_read_interval);
+	return 0;
+}
+
 static const struct dsa_switch_ops ksz_switch_ops = {
 	.get_tag_protocol	= ksz_get_tag_protocol,
 	.connect_tag_protocol   = ksz_connect_tag_protocol,
@@ -4626,6 +4643,8 @@ static const struct dsa_switch_ops ksz_switch_ops = {
 	.port_max_mtu		= ksz_max_mtu,
 	.get_wol		= ksz_get_wol,
 	.set_wol		= ksz_set_wol,
+	.suspend		= ksz_suspend,
+	.resume			= ksz_resume,
 	.get_ts_info		= ksz_get_ts_info,
 	.port_hwtstamp_get	= ksz_hwtstamp_get,
 	.port_hwtstamp_set	= ksz_hwtstamp_set,
@@ -5126,6 +5145,24 @@ void ksz_switch_remove(struct ksz_device *dev)
 }
 EXPORT_SYMBOL(ksz_switch_remove);
 
+#ifdef CONFIG_PM_SLEEP
+int ksz_switch_suspend(struct device *dev)
+{
+	struct ksz_device *priv = dev_get_drvdata(dev);
+
+	return dsa_switch_suspend(priv->ds);
+}
+EXPORT_SYMBOL(ksz_switch_suspend);
+
+int ksz_switch_resume(struct device *dev)
+{
+	struct ksz_device *priv = dev_get_drvdata(dev);
+
+	return dsa_switch_resume(priv->ds);
+}
+EXPORT_SYMBOL(ksz_switch_resume);
+#endif
+
 MODULE_AUTHOR("Woojung Huh <Woojung.Huh@microchip.com>");
 MODULE_DESCRIPTION("Microchip KSZ Series Switch DSA Driver");
 MODULE_LICENSE("GPL");