[PATCH 2/3] net: pse-pd: prevent regulator cleanup from disabling unclaimed PSE PIs

[Carlo Szelinsky <github@szelinsky.de>]

When a PSE controller driver is loaded as a module, its PI regulators
are registered before any consumer (PHY) acquires the corresponding PSE
control via of_pse_control_get(). The regulator framework's
regulator_late_cleanup then calls pse_pi_is_enabled(), which queries
hardware and sees the PI is enabled. Since no consumer holds it
(use_count == 0), regulator_late_cleanup disables it, killing PoE.

Add an admin_state_synced flag to struct pse_pi that is set when a
consumer first acquires the PSE control and syncs admin_state_enabled
from hardware. In pse_pi_is_enabled(), report unsynchronized PIs as
disabled so regulator_late_cleanup skips them.

This preserves the existing dual-path behavior: software-tracked state
for software-controlled power domains, and hardware queries for
hardware-controlled domains. The admin_state_synced flag is only false
before the first consumer acquisition, which is the exact window where
regulator_late_cleanup could incorrectly disable the PI.

Signed-off-by: Carlo Szelinsky <github@szelinsky.de>
---
 drivers/net/pse-pd/pse_core.c | 13 +++++++++++++
 include/linux/pse-pd/pse.h    |  1 +
 2 files changed, 14 insertions(+)

diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index 3beaaaeec9e1..566b07c336bf 100644
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -421,6 +421,18 @@ static int pse_pi_is_enabled(struct regulator_dev *rdev)
 
 	id = rdev_get_id(rdev);
 	mutex_lock(&pcdev->lock);
+
+	/*
+	 * Report the PI as disabled until a consumer has acquired it
+	 * and synced admin_state_enabled from hardware. This prevents
+	 * regulator_late_cleanup from disabling unclaimed PSE PIs
+	 * when the PSE controller driver loads as a module.
+	 */
+	if (!pcdev->pi[id].admin_state_synced) {
+		ret = 0;
+		goto out;
+	}
+
 	if (pse_pw_d_is_sw_pw_control(pcdev, pcdev->pi[id].pw_d)) {
 		ret = pcdev->pi[id].admin_state_enabled;
 		goto out;
@@ -1431,6 +1443,7 @@ pse_control_get_internal(struct pse_controller_dev *pcdev, unsigned int index,
 		goto free_psec;
 
 	pcdev->pi[index].admin_state_enabled = ret;
+	pcdev->pi[index].admin_state_synced = true;
 	psec->ps = devm_regulator_get_exclusive(pcdev->dev,
 						rdev_get_name(pcdev->pi[index].rdev));
 	if (IS_ERR(psec->ps)) {
diff --git a/include/linux/pse-pd/pse.h b/include/linux/pse-pd/pse.h
index 4e5696cfade7..b86cce740551 100644
--- a/include/linux/pse-pd/pse.h
+++ b/include/linux/pse-pd/pse.h
@@ -260,6 +260,7 @@ struct pse_pi {
 	struct device_node *np;
 	struct regulator_dev *rdev;
 	bool admin_state_enabled;
+	bool admin_state_synced;
 	struct pse_power_domain *pw_d;
 	int prio;
 	bool isr_pd_detected;
-- 
2.43.0