[PATCH net v2] net: micrel: Fix lan8841_config_intr after getting out of sleep mode

[PATCH net v2] net: micrel: Fix lan8841_config_intr after getting out of sleep mode

[Horatiu Vultur]

When the interrupt is enabled, the function lan8841_config_intr tries to
clear any pending interrupts by reading the interrupt status, then
checks the return value for errors and then continue to enable the
interrupt. It has been seen that once the system gets out of sleep mode,
the interrupt status has the value 0x400 meaning that the PHY detected
that the link was in low power. That is correct value but the problem is
that the check is wrong.  We try to check for errors but we return an
error also in this case which is not an error. Therefore fix this by
returning only when there is an error.

Fixes: a8f1a19d27ef ("net: micrel: Add support for lan8841 PHY")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
v1->v2:
- do the same also in case the interrupts are disabled.
---
 drivers/net/phy/micrel.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 13e30ea7eec5d..c0773d74d5104 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -4029,7 +4029,7 @@ static int lan8841_config_intr(struct phy_device *phydev)
 
 	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
 		err = phy_read(phydev, LAN8814_INTS);
-		if (err)
+		if (err < 0)
 			return err;
 
 		/* Enable / disable interrupts. It is OK to enable PTP interrupt
@@ -4045,6 +4045,14 @@ static int lan8841_config_intr(struct phy_device *phydev)
 			return err;
 
 		err = phy_read(phydev, LAN8814_INTS);
+		if (err < 0)
+			return err;
+
+		/* Getting a positive value doesn't mean that is an error, it
+		 * just indicates what was the status. Therefore make sure to
+		 * clear the value and say that there is no error.
+		 */
+		err = 0;
 	}
 
 	return err;
-- 
2.34.1

RE: [EXTERNAL] [PATCH net v2] net: micrel: Fix lan8841_config_intr after getting out of sleep mode

[Suman Ghosh]

>diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c index
>13e30ea7eec5d..c0773d74d5104 100644
>--- a/drivers/net/phy/micrel.c
>+++ b/drivers/net/phy/micrel.c
>@@ -4029,7 +4029,7 @@ static int lan8841_config_intr(struct phy_device
>*phydev)
>
> 	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
> 		err = phy_read(phydev, LAN8814_INTS);
>-		if (err)
>+		if (err < 0)
> 			return err;
>
> 		/* Enable / disable interrupts. It is OK to enable PTP
>interrupt @@ -4045,6 +4045,14 @@ static int lan8841_config_intr(struct
>phy_device *phydev)
> 			return err;
>
> 		err = phy_read(phydev, LAN8814_INTS);
>+		if (err < 0)
>+			return err;
>+
>+		/* Getting a positive value doesn't mean that is an error, it
>+		 * just indicates what was the status. Therefore make sure to
>+		 * clear the value and say that there is no error.
>+		 */
>+		err = 0;
[Suman] Looks good to me.
Reviewed-by: Suman Ghosh <sumang@marvell.com>

> 	}
>
> 	return err;
>--
>2.34.1

Re: [PATCH net v2] net: micrel: Fix lan8841_config_intr after getting out of sleep mode

[Andrew Lunn]

On Fri, May 24, 2024 at 10:53:50AM +0200, Horatiu Vultur wrote:
> When the interrupt is enabled, the function lan8841_config_intr tries to
> clear any pending interrupts by reading the interrupt status, then
> checks the return value for errors and then continue to enable the
> interrupt. It has been seen that once the system gets out of sleep mode,
> the interrupt status has the value 0x400 meaning that the PHY detected
> that the link was in low power. That is correct value but the problem is
> that the check is wrong.  We try to check for errors but we return an
> error also in this case which is not an error. Therefore fix this by
> returning only when there is an error.
> 
> Fixes: a8f1a19d27ef ("net: micrel: Add support for lan8841 PHY")
> Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>

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

    Andrew

Re: [PATCH net v2] net: micrel: Fix lan8841_config_intr after getting out of sleep mode

[Russell King (Oracle)]

On Fri, May 24, 2024 at 10:53:50AM +0200, Horatiu Vultur wrote:
> When the interrupt is enabled, the function lan8841_config_intr tries to
> clear any pending interrupts by reading the interrupt status, then
> checks the return value for errors and then continue to enable the
> interrupt. It has been seen that once the system gets out of sleep mode,
> the interrupt status has the value 0x400 meaning that the PHY detected
> that the link was in low power. That is correct value but the problem is
> that the check is wrong.  We try to check for errors but we return an
> error also in this case which is not an error. Therefore fix this by
> returning only when there is an error.
> 
> Fixes: a8f1a19d27ef ("net: micrel: Add support for lan8841 PHY")
> Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>

LGTM.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

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Re: [PATCH net v2] net: micrel: Fix lan8841_config_intr after getting out of sleep mode

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 24 May 2024 10:53:50 +0200 you wrote:
> When the interrupt is enabled, the function lan8841_config_intr tries to
> clear any pending interrupts by reading the interrupt status, then
> checks the return value for errors and then continue to enable the
> interrupt. It has been seen that once the system gets out of sleep mode,
> the interrupt status has the value 0x400 meaning that the PHY detected
> that the link was in low power. That is correct value but the problem is
> that the check is wrong.  We try to check for errors but we return an
> error also in this case which is not an error. Therefore fix this by
> returning only when there is an error.
> 
> [...]

Here is the summary with links:
  - [net,v2] net: micrel: Fix lan8841_config_intr after getting out of sleep mode
    https://git.kernel.org/netdev/net/c/4fb679040d9f

You are awesome, thank you!
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