[PATCH wireless-next v2 1/2] wifi: mt76: share the throughput LED trigger across bands

[Petr Wozniak]

ieee80211_create_tpt_led_trigger() creates one trigger per ieee80211_hw
and returns NULL with a WARN_ON() if called again for the same hw.

Under the single-wiphy MLO model each band registers its own LED classdev
for the same hw, and the bands can be initialised in any order. Create the
trigger on the first mt76_led_init() call, stash it on the primary phy's
classdev and let the other bands reuse it. This avoids the WARN_ON() splat
and gives every band the same throughput trigger regardless of init order.

Signed-off-by: Petr Wozniak <petr.wozniak at gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mac80211.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c
index 13c4e8abe..0c6641050 100644
--- a/drivers/net/wireless/mediatek/mt76/mac80211.c
+++ b/drivers/net/wireless/mediatek/mt76/mac80211.c
@@ -228,11 +228,19 @@ static int mt76_led_init(struct mt76_phy *phy)
 		 wiphy_name(hw->wiphy));
 
 	phy->leds.cdev.name = phy->leds.name;
-	phy->leds.cdev.default_trigger =
-		ieee80211_create_tpt_led_trigger(hw,
-					IEEE80211_TPT_LEDTRIG_FL_RADIO,
-					mt76_tpt_blink,
-					ARRAY_SIZE(mt76_tpt_blink));
+	/* The throughput trigger is created once per ieee80211_hw. Under
+	 * single-wiphy MLO every band registers its own LED classdev for the
+	 * same hw and the bands can come up in any order, so create the trigger
+	 * on the first call, stash it on the primary phy and let other bands
+	 * reuse it; calling it again would trip a WARN_ON().
+	 */
+	if (!dev->phy.leds.cdev.default_trigger)
+		dev->phy.leds.cdev.default_trigger =
+			ieee80211_create_tpt_led_trigger(hw,
+				IEEE80211_TPT_LEDTRIG_FL_RADIO,
+				mt76_tpt_blink,
+				ARRAY_SIZE(mt76_tpt_blink));
+	phy->leds.cdev.default_trigger = dev->phy.leds.cdev.default_trigger;
 
 	dev_info(dev->dev,
 		"registering led '%s'\n", phy->leds.name);
-- 
2.51.0