[v4] i2c: npcm: Add clock toggle recovery

[PATCH v4] i2c: npcm: Add clock toggle recovery

Posted by mohammed.0.elbadry@gmail.com 8 months, 3 weeks ago

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 2fe68615942e..caf9aa1e6319 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
+			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return -ENXIO;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.49.0.472.ge94155a9ec-goog

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

Posted by Andi Shyti 8 months, 1 week ago

Hi Mohammed,

On Fri, Mar 28, 2025 at 07:32:50PM +0000, mohammed.0.elbadry@gmail.com wrote:
> From: Tali Perry <tali.perry1@gmail.com>
> 
> During init of the bus, the module checks that the bus is idle.
> If one of the lines are stuck try to recover them first before failing.
> Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> 
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
> ---

we are missing the changelog here. You are at v4 and I need to
see the changes between the versions. For now it's OK, please,
next time don't forget to add the changelog.

One more thing, no need to send patches as --in-reply-to your
previous patch.

>  drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 2fe68615942e..caf9aa1e6319 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
>  
>  	/* Check HW is OK: SDA and SCL should be high at this point. */
>  	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> -		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> -		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> -			npcm_i2c_get_SCL(&bus->adap));
> -		return -ENXIO;
> +		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,

the space at the beginning of the line should be removed. I will
take care of it if you won't be asked to send a new version.

> +				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> +		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> +			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> +				bus->num, npcm_i2c_get_SDA(&bus->adap),
> +				npcm_i2c_get_SCL(&bus->adap));
> +			return -ENXIO;

why don't we return the error coming from
npcm_i2c_recovery_tgclk() instead of forcing it to ENXIO?

Thanks,
Andi

> +		}
>  	}
>  
>  	npcm_i2c_int_enable(bus, true);
> -- 
> 2.49.0.472.ge94155a9ec-goog
>

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

Posted by Mohammed Elbadry 8 months, 1 week ago

Hi Andi,

On Sun, Apr 13, 2025 at 4:06 PM Andi Shyti <andi.shyti@kernel.org> wrote:
>
> Hi Mohammed,
>
> On Fri, Mar 28, 2025 at 07:32:50PM +0000, mohammed.0.elbadry@gmail.com wrote:
> > From: Tali Perry <tali.perry1@gmail.com>
> >
> > During init of the bus, the module checks that the bus is idle.
> > If one of the lines are stuck try to recover them first before failing.
> > Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> >
> > Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> > Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
> > ---
>
> we are missing the changelog here. You are at v4 and I need to
> see the changes between the versions. For now it's OK, please,
> next time don't forget to add the changelog.
I understand, I will do that, thank you.

>
> One more thing, no need to send patches as --in-reply-to your
> previous patch.
>
> >  drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> > index 2fe68615942e..caf9aa1e6319 100644
> > --- a/drivers/i2c/busses/i2c-npcm7xx.c
> > +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> > @@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
> >
> >       /* Check HW is OK: SDA and SCL should be high at this point. */
> >       if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> > -             dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> > -             dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> > -                     npcm_i2c_get_SCL(&bus->adap));
> > -             return -ENXIO;
> > +             dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
>
> the space at the beginning of the line should be removed. I will
> take care of it if you won't be asked to send a new version.
>
Got it, thank you.
> > +                              npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> > +             if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> > +                     dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> > +                             bus->num, npcm_i2c_get_SDA(&bus->adap),
> > +                             npcm_i2c_get_SCL(&bus->adap));
> > +                     return -ENXIO;
>
> why don't we return the error coming from
> npcm_i2c_recovery_tgclk() instead of forcing it to ENXIO?

The error that comes from the current driver is only -ENOTRECOVERABLE.
I do not see why we cannot return that error instead. I understand the
difference between both states; however, from the driver's
perspective, on initialization, ENXIO and ENOTRECOVERABLE behavior is
identical in that state.

ENXIO was what the driver returned by default without trying to
recover. Do you recommend changing it? Let me know. I am happy to send
the v5 patch with the change and address the above comments, too.

Thank you,
Mo
>
> Thanks,
> Andi
>
> > +             }
> >       }
> >
> >       npcm_i2c_int_enable(bus, true);
> > --
> > 2.49.0.472.ge94155a9ec-goog
> >

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

Posted by Andi Shyti 8 months ago

Hi Mohammed,

...

> > > +                              npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> > > +             if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> > > +                     dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> > > +                             bus->num, npcm_i2c_get_SDA(&bus->adap),
> > > +                             npcm_i2c_get_SCL(&bus->adap));
> > > +                     return -ENXIO;
> >
> > why don't we return the error coming from
> > npcm_i2c_recovery_tgclk() instead of forcing it to ENXIO?
> 
> The error that comes from the current driver is only -ENOTRECOVERABLE.
> I do not see why we cannot return that error instead. I understand the
> difference between both states; however, from the driver's
> perspective, on initialization, ENXIO and ENOTRECOVERABLE behavior is
> identical in that state.

I think it makes more sense to return the error we receive from
npcm_i2c_recovery_tgclk(). Then we can discuss whether that error
is correct or not, but that's a different topic.

> ENXIO was what the driver returned by default without trying to
> recover. Do you recommend changing it? Let me know. I am happy to send
> the v5 patch with the change and address the above comments, too.

Yes, please do.

Andi

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

Posted by Mukesh Kumar Savaliya 8 months, 3 weeks ago

Looks good to me.

On 3/29/2025 1:02 AM, mohammed.0.elbadry@gmail.com wrote:
> From: Tali Perry <tali.perry1@gmail.com>
> 
> During init of the bus, the module checks that the bus is idle.
> If one of the lines are stuck try to recover them first before failing.
> Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> 
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
> ---
>   drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 2fe68615942e..caf9aa1e6319 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
>   
>   	/* Check HW is OK: SDA and SCL should be high at this point. */
>   	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> -		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> -		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> -			npcm_i2c_get_SCL(&bus->adap));
> -		return -ENXIO;
> +		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
> +				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> +		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> +			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> +				bus->num, npcm_i2c_get_SDA(&bus->adap),
> +				npcm_i2c_get_SCL(&bus->adap));
> +			return -ENXIO;
> +		}
>   	}
>   
>   	npcm_i2c_int_enable(bus, true);

[PATCH v5] i2c: npcm: Add clock toggle recovery

Posted by Mohammed Elbadry 6 months, 3 weeks ago

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index de713b5747fe..4738fc450a6b 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2178,10 +2178,15 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		ret = npcm_i2c_recovery_tgclk(&bus->adap);
+		if (ret) {
+			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return ret;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.39.5 (Apple Git-154)

[PATCH v5] i2c: npcm: Add clock toggle recovery

Posted by Mohammed Elbadry 6 months, 3 weeks ago

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index de713b5747fe..0757a23dc1cd 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2178,10 +2178,15 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		ret = npcm_i2c_recovery_tgclk(&bus->adap);
+		if (ret) {
+			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return ret;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.39.5 (Apple Git-154)