[PATCH net v3 2/2] net: phy: qca808x: keep an explicit active-high LED across the reset

[Donggeun Yoo <donggeunyoo.kernel@gmail.com>]

With the previous patch an 'active-high' LED node is accepted, so
led_polarity_mode can now hold 0. qca808x_config_init() only re-asserts
QCA808X_LED_ACTIVE_HIGH when the mode is -1, the value that means device
tree asked for nothing, so an explicit active-high does not reach the
register.

That matters because the bit does not survive a reset. phy_init_hw() runs
.soft_reset before .config_init on every attach and resume, and
commit f203c8c77c76 ("net: phy: qcom: qca808x: default to LED active High if not set")
records why: "on PHY reset, the Active High bit is not set resulting in
the LED driven as active-low". The polarity written from device tree
during phy_probe() is therefore gone by the time the link comes up, and
the LED runs inverted.

Re-assert the bit for anything other than an explicit active-low, which
is the one case that wants it clear and gets that from the reset for
free. Name the unset value while here: led_polarity_mode otherwise
holds a PHY_LED_ACTIVE_* value, so spelling the comparison
PHY_LED_ACTIVE_LOW says what it means where -1, 0 and 1 did not.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260908105959.70453-1-donggeunyoo.kernel%40gmail.com
Cc: stable@vger.kernel.org
Fixes: a274465cc3be ("net: phy: support 'active-high' property for PHY LEDs")
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Assisted-by: Claude:claude-fable-5
---
Tested in QEMU against a synthetic MDIO bus answering as a QCA8081, with
the reset clearing BIT(6). With only 1/2 applied an 'active-high' node
comes up inverted; see the cover letter.

 drivers/net/phy/qcom/qca808x.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/qcom/qca808x.c b/drivers/net/phy/qcom/qca808x.c
index 3ba58f14e248..bab26e4c6140 100644
--- a/drivers/net/phy/qcom/qca808x.c
+++ b/drivers/net/phy/qcom/qca808x.c
@@ -87,6 +87,9 @@
 
 #define QCA8081_PHY_ID				0x004dd101
 
+/* led_polarity_mode otherwise holds a PHY_LED_ACTIVE_* value */
+#define QCA808X_PHY_LED_UNSET			-1
+
 MODULE_DESCRIPTION("Qualcomm Atheros QCA808X PHY driver");
 MODULE_AUTHOR("Matus Ujhelyi");
 MODULE_LICENSE("GPL");
@@ -187,8 +190,7 @@ static int qca808x_probe(struct phy_device *phydev)
 	if (!priv)
 		return -ENOMEM;
 
-	/* Init LED polarity mode to -1 */
-	priv->led_polarity_mode = -1;
+	priv->led_polarity_mode = QCA808X_PHY_LED_UNSET;
 
 	phydev->priv = priv;
 
@@ -200,8 +202,8 @@ static int qca808x_config_init(struct phy_device *phydev)
 	struct qca808x_priv *priv = phydev->priv;
 	int ret;
 
-	/* Default to LED Active High if active-low not in DT */
-	if (priv->led_polarity_mode == -1) {
+	/* Set LED Active High unless active-low was requested in DT */
+	if (priv->led_polarity_mode != PHY_LED_ACTIVE_LOW) {
 		ret = phy_set_bits_mmd(phydev, MDIO_MMD_AN,
 				       QCA808X_MMD7_LED_POLARITY_CTRL,
 				       QCA808X_LED_ACTIVE_HIGH);
@@ -615,7 +617,7 @@ static int qca808x_led_polarity_set(struct phy_device *phydev, int index,
 	 * To detect this, check if last requested polarity mode
 	 * match the new one.
 	 */
-	if (priv->led_polarity_mode >= 0 &&
+	if (priv->led_polarity_mode != QCA808X_PHY_LED_UNSET &&
 	    priv->led_polarity_mode != active_low) {
 		phydev_err(phydev, "PHY polarity is global. Mismatched polarity on different LED\n");
 		return -EINVAL;
-- 
2.53.0