linux-kernel - [PATCH net] net: pse-pd: Fix enabled status mismatch

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Message-Id: <20241002121706.246143-1-kory.maincent@bootlin.com>
Date: Wed,  2 Oct 2024 14:17:05 +0200
From: Kory Maincent <kory.maincent@...tlin.com>
To: Andrew Lunn <andrew@...n.ch>,
	"Kory Maincent (Dent Project)" <kory.maincent@...tlin.com>,
	Jakub Kicinski <kuba@...nel.org>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Kyle Swenson <kyle.swenson@....tech>,
	thomas.petazzoni@...tlin.com,
	Oleksij Rempel <o.rempel@...gutronix.de>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Paolo Abeni <pabeni@...hat.com>
Subject: [PATCH net] net: pse-pd: Fix enabled status mismatch

PSE controllers like the TPS23881 can forcefully turn off their
configuration state. In such cases, the is_enabled() and get_status()
callbacks will report the PSE as disabled, while admin_state_enabled
will show it as enabled. This mismatch can lead the user to attempt
to enable it, but no action is taken as admin_state_enabled remains set.

The solution is to disable the PSE before enabling it, ensuring the
actual status matches admin_state_enabled.

Fixes: d83e13761d5b ("net: pse-pd: Use regulator framework within PSE framework")
Signed-off-by: Kory Maincent <kory.maincent@...tlin.com>
---

FYI: Saving the enabled state in the driver is not a viable solution, as a
reboot may cause a mismatch between the real and software-saved states.
---
 drivers/net/pse-pd/pse_core.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index 4f032b16a8a0..f8e6854781e6 100644
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -785,6 +785,17 @@ static int pse_ethtool_c33_set_config(struct pse_control *psec,
 	 */
 	switch (config->c33_admin_control) {
 	case ETHTOOL_C33_PSE_ADMIN_STATE_ENABLED:
+		/* We could have mismatch between admin_state_enabled and
+		 * state reported by regulator_is_enabled. This can occur when
+		 * the PI is forcibly turn off by the controller. Call
+		 * regulator_disable on that case to fix the counters state.
+		 */
+		if (psec->pcdev->pi[psec->id].admin_state_enabled &&
+		    !regulator_is_enabled(psec->ps)) {
+			err = regulator_disable(psec->ps);
+			if (err)
+				break;
+		}
 		if (!psec->pcdev->pi[psec->id].admin_state_enabled)
 			err = regulator_enable(psec->ps);
 		break;
-- 
2.34.1