[PATCH net] net: phy: dp83867: restore the LED polarity after a soft reset

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

dp83867_led_polarity_set() programs the LEDCR2 polarity bit for a
DT-configured LED. It runs once, from phy_probe() via of_phy_leds().
Every phy_init_hw() afterwards (phy_attach_direct(), mdio_bus_phy_resume(),
and MAC drivers such as fec_main.c) calls .soft_reset first, and
dp83867_phy_reset() issues DP83867_SW_RESET, which restores register
defaults. config_init does not touch LEDCR2 and the requested value is
not cached, so a DT-configured LED polarity is lost from the first
attach onward.

The soft reset is the only path that clears LEDCR2, and phy_init_hw()
always follows it with config_init. Cache the requested bits and reapply
them from dp83867_config_init(). aqr_gen1_config_init() recovers from the
same reset the same way (61578f679378).

Fixes: 447b80a9330e ("net: phy: dp83867: Add support for active-low LEDs")
Assisted-by: Claude:claude-fable-5
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
---
The soft-reset regression was flagged by an automated analysis of an
earlier posting of the active-high series. Compile-tested and
call-chain-traced only; I have no affected hardware.

 drivers/net/phy/dp83867.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index 88255e92b4cd..c9c3b0062cc7 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -196,6 +196,8 @@ struct dp83867_private {
 	bool set_clk_output;
 	u32 clk_output_sel;
 	bool sgmii_ref_clk_en;
+	u16 led_polarity;
+	u16 led_polarity_mask;
 };
 
 static int dp83867_ack_interrupt(struct phy_device *phydev)
@@ -896,6 +898,15 @@ static int dp83867_config_init(struct phy_device *phydev)
 			       mask, val);
 	}
 
+	/* Restore the LED polarity dropped by the soft reset in phy_init_hw() */
+	if (dp83867->led_polarity_mask) {
+		ret = phy_modify(phydev, DP83867_LEDCR2,
+				 dp83867->led_polarity_mask,
+				 dp83867->led_polarity);
+		if (ret)
+			return ret;
+	}
+
 	return 0;
 }
 
@@ -1141,8 +1152,10 @@ static int dp83867_led_hw_control_get(struct phy_device *phydev, u8 index,
 static int dp83867_led_polarity_set(struct phy_device *phydev, int index,
 				    unsigned long modes)
 {
+	struct dp83867_private *dp83867 = phydev->priv;
+	u16 mask = DP83867_LED_POLARITY(index);
 	/* Default active high */
-	u16 polarity = DP83867_LED_POLARITY(index);
+	u16 polarity = mask;
 	u32 mode;
 
 	for_each_set_bit(mode, &modes, __PHY_LED_MODES_NUM) {
@@ -1154,8 +1167,11 @@ static int dp83867_led_polarity_set(struct phy_device *phydev, int index,
 			return -EINVAL;
 		}
 	}
-	return phy_modify(phydev, DP83867_LEDCR2,
-			  DP83867_LED_POLARITY(index), polarity);
+
+	dp83867->led_polarity_mask |= mask;
+	dp83867->led_polarity = (dp83867->led_polarity & ~mask) | polarity;
+
+	return phy_modify(phydev, DP83867_LEDCR2, mask, polarity);
 }
 
 static unsigned int dp83867_inband_caps(struct phy_device *phydev,
-- 
2.53.0