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@bootlin.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

On Wed, Oct 02, 2024 at 02:17:05PM +0200, Kory Maincent wrote:
> 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@bootlin.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.

This seems O.K. to me.

I'm assuming the controller has turned the configuration state to off
to stop the magic smoke escaping? Is there any sort of notification of
this?  Does it raise an interrupt? Sometime in the future we might
want to add a netlink notification about this?

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

On Wed, 2 Oct 2024 14:38:19 +0200
Andrew Lunn <andrew@lunn.ch> wrote:

> On Wed, Oct 02, 2024 at 02:17:05PM +0200, Kory Maincent wrote:
> > 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@bootlin.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.  
> 
> This seems O.K. to me.
> 
> I'm assuming the controller has turned the configuration state to off
> to stop the magic smoke escaping? Is there any sort of notification of
> this?  Does it raise an interrupt? Sometime in the future we might
> want to add a netlink notification about this?

Thanks for your review!

Yes, in case of over-current or over-temperature, there is an interrupt. The
netlink notifications support will arrive soon in the series in progress.

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com