[PATCH 0/4] Apple/PASemi i2c error recovery fixes

[PATCH 0/4] Apple/PASemi i2c error recovery fixes

[Sven Peter via B4 Relay]

Hi,

This series adds a few fixes/improvements to the error recovery for
Apple/PASemi i2c controllers.
The patches have been in our downstream tree and were originally used
to debug a rare glitch caused by clock strechting but are useful in
general. We haven't seen the controller misbehave since adding these.

Best,

Sven

Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
Hector Martin (3):
      i2c: pasemi: Improve error recovery
      i2c: pasemi: Enable the unjam machine
      i2c: pasemi: Log bus reset causes

Sven Peter (1):
      i2c: pasemi: Add registers bits and switch to BIT()

 drivers/i2c/busses/i2c-pasemi-core.c | 121 ++++++++++++++++++++++++++---------
 1 file changed, 92 insertions(+), 29 deletions(-)
---
base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
change-id: 20250220-pasemi-fixes-916cb77404ba

Best regards,
-- 
Sven Peter <sven@svenpeter.dev>

[PATCH 1/4] i2c: pasemi: Add registers bits and switch to BIT()

[Sven Peter via B4 Relay]

From: Sven Peter <sven@svenpeter.dev>

Add the missing register bits to the defines and also switch
those to use the BIT macro which is much more readable than
using hardcoded masks

Co-developed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
 drivers/i2c/busses/i2c-pasemi-core.c | 40 ++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pasemi-core.c b/drivers/i2c/busses/i2c-pasemi-core.c
index dac694a9d781..bd128ab2e2eb 100644
--- a/drivers/i2c/busses/i2c-pasemi-core.c
+++ b/drivers/i2c/busses/i2c-pasemi-core.c
@@ -5,6 +5,7 @@
  * SMBus host driver for PA Semi PWRficient
  */
 
+#include <linux/bitfield.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/kernel.h>
@@ -26,21 +27,30 @@
 #define REG_REV		0x28
 
 /* Register defs */
-#define MTXFIFO_READ	0x00000400
-#define MTXFIFO_STOP	0x00000200
-#define MTXFIFO_START	0x00000100
-#define MTXFIFO_DATA_M	0x000000ff
-
-#define MRXFIFO_EMPTY	0x00000100
-#define MRXFIFO_DATA_M	0x000000ff
-
-#define SMSTA_XEN	0x08000000
-#define SMSTA_MTN	0x00200000
-
-#define CTL_MRR		0x00000400
-#define CTL_MTR		0x00000200
-#define CTL_EN		0x00000800
-#define CTL_CLK_M	0x000000ff
+#define MTXFIFO_READ	BIT(10)
+#define MTXFIFO_STOP	BIT(9)
+#define MTXFIFO_START	BIT(8)
+#define MTXFIFO_DATA_M	GENMASK(7, 0)
+
+#define MRXFIFO_EMPTY	BIT(8)
+#define MRXFIFO_DATA_M	GENMASK(7, 0)
+
+#define SMSTA_XIP	BIT(28)
+#define SMSTA_XEN	BIT(27)
+#define SMSTA_JMD	BIT(25)
+#define SMSTA_JAM	BIT(24)
+#define SMSTA_MTO	BIT(23)
+#define SMSTA_MTA	BIT(22)
+#define SMSTA_MTN	BIT(21)
+#define SMSTA_MRNE	BIT(19)
+#define SMSTA_MTE	BIT(16)
+#define SMSTA_TOM	BIT(6)
+
+#define CTL_EN		BIT(11)
+#define CTL_MRR		BIT(10)
+#define CTL_MTR		BIT(9)
+#define CTL_UJM		BIT(8)
+#define CTL_CLK_M	GENMASK(7, 0)
 
 static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
 {

-- 
2.34.1

Re: [PATCH 1/4] i2c: pasemi: Add registers bits and switch to BIT()

[Andi Shyti]

Hi Sven,

On Sat, Feb 22, 2025 at 01:38:33PM +0000, Sven Peter via B4 Relay wrote:
> From: Sven Peter <sven@svenpeter.dev>
> 
> Add the missing register bits to the defines and also switch
> those to use the BIT macro which is much more readable than
> using hardcoded masks
> 
> Co-developed-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Sven Peter <sven@svenpeter.dev>

Just this patch merged to i2c/i2c-host.

Patch 3 and 4 look good, just some comments on patch 2.

Thanks,
Andi

Re: [PATCH 1/4] i2c: pasemi: Add registers bits and switch to BIT()

[Andy Shevchenko]

Thu, Mar 20, 2025 at 01:23:25AM +0100, Andi Shyti kirjoitti:
> Hi Sven,
> 
> On Sat, Feb 22, 2025 at 01:38:33PM +0000, Sven Peter via B4 Relay wrote:
> > From: Sven Peter <sven@svenpeter.dev>
> > 
> > Add the missing register bits to the defines and also switch
> > those to use the BIT macro which is much more readable than
> > using hardcoded masks
> > 
> > Co-developed-by: Hector Martin <marcan@marcan.st>
> > Signed-off-by: Hector Martin <marcan@marcan.st>
> > Signed-off-by: Sven Peter <sven@svenpeter.dev>
> 
> Just this patch merged to i2c/i2c-host.

This needs an update as well. The proper header for BIT() et al. is bits.h.
bitfield.h is for FIELD_*() et al.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/4] i2c: pasemi: Add registers bits and switch to BIT()

[Sven Peter]

On Sat, Mar 22, 2025, at 14:23, Andy Shevchenko wrote:
> Thu, Mar 20, 2025 at 01:23:25AM +0100, Andi Shyti kirjoitti:
>> Hi Sven,
>> 
>> On Sat, Feb 22, 2025 at 01:38:33PM +0000, Sven Peter via B4 Relay wrote:
>> > From: Sven Peter <sven@svenpeter.dev>
>> > 
>> > Add the missing register bits to the defines and also switch
>> > those to use the BIT macro which is much more readable than
>> > using hardcoded masks
>> > 
>> > Co-developed-by: Hector Martin <marcan@marcan.st>
>> > Signed-off-by: Hector Martin <marcan@marcan.st>
>> > Signed-off-by: Sven Peter <sven@svenpeter.dev>
>> 
>> Just this patch merged to i2c/i2c-host.
>
> This needs an update as well. The proper header for BIT() et al. is bits.h.
> bitfield.h is for FIELD_*() et al.

Ugh, good catch. Since this commit is already on the way upstream I'll send a fix
(and another one to sort the headers alphabetically while I'm at it anyway).


Thanks,


Sven

[PATCH 2/4] i2c: pasemi: Improve error recovery

[Sven Peter via B4 Relay]

From: Hector Martin <marcan@marcan.st>

The hardware (supposedly) has a 25ms timeout for clock stretching
and the driver uses 100ms which should be plenty. The error
reocvery itself is however lacking.

Add handling for all the missing error condition, and better recovery in
pasemi_smb_clear(). Also move the timeout to a #define since it's used
in multiple places now.

Signed-off-by: Hector Martin <marcan@marcan.st>
[sven: adjusted commit message after splitting the commit into two]
Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
 drivers/i2c/busses/i2c-pasemi-core.c | 70 +++++++++++++++++++++++++++++-------
 1 file changed, 58 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pasemi-core.c b/drivers/i2c/busses/i2c-pasemi-core.c
index bd128ab2e2eb..770b86b92a10 100644
--- a/drivers/i2c/busses/i2c-pasemi-core.c
+++ b/drivers/i2c/busses/i2c-pasemi-core.c
@@ -52,6 +52,8 @@
 #define CTL_UJM		BIT(8)
 #define CTL_CLK_M	GENMASK(7, 0)
 
+#define TRANSFER_TIMEOUT_MS	100
+
 static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
 {
 	dev_dbg(smbus->dev, "smbus write reg %x val %08x\n", reg, val);
@@ -80,23 +82,45 @@ static void pasemi_reset(struct pasemi_smbus *smbus)
 	reinit_completion(&smbus->irq_completion);
 }
 
-static void pasemi_smb_clear(struct pasemi_smbus *smbus)
+static int pasemi_smb_clear(struct pasemi_smbus *smbus)
 {
 	unsigned int status;
+	int timeout = TRANSFER_TIMEOUT_MS;
 
 	status = reg_read(smbus, REG_SMSTA);
+
+	/* First wait for the bus to go idle */
+	while ((status & (SMSTA_XIP | SMSTA_JAM)) && timeout--) {
+		msleep(1);
+		status = reg_read(smbus, REG_SMSTA);
+	}
+
+	if (timeout < 0) {
+		dev_warn(smbus->dev, "Bus is still stuck (status 0x%08x)\n", status);
+		return -EIO;
+	}
+
+	/* If any badness happened or there is data in the FIFOs, reset the FIFOs */
+	if ((status & (SMSTA_MRNE | SMSTA_JMD | SMSTA_MTO | SMSTA_TOM | SMSTA_MTN | SMSTA_MTA)) ||
+		!(status & SMSTA_MTE))
+		pasemi_reset(smbus);
+
+	/* Clear the flags */
 	reg_write(smbus, REG_SMSTA, status);
+
+	return 0;
 }
 
 static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
 {
-	int timeout = 100;
+	int timeout = TRANSFER_TIMEOUT_MS;
 	unsigned int status;
 
 	if (smbus->use_irq) {
 		reinit_completion(&smbus->irq_completion);
-		reg_write(smbus, REG_IMASK, SMSTA_XEN | SMSTA_MTN);
-		wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(100));
+		/* XEN should be set when a transaction terminates, whether due to error or not */
+		reg_write(smbus, REG_IMASK, SMSTA_XEN);
+		wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(timeout));
 		reg_write(smbus, REG_IMASK, 0);
 		status = reg_read(smbus, REG_SMSTA);
 	} else {
@@ -107,16 +131,36 @@ static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
 		}
 	}
 
-	/* Got NACK? */
-	if (status & SMSTA_MTN)
-		return -ENXIO;
+	/* Controller timeout? */
+	if (status & SMSTA_TOM) {
+		dev_warn(smbus->dev, "Controller timeout, status 0x%08x\n", status);
+		return -EIO;
+	}
 
-	if (timeout < 0) {
-		dev_warn(smbus->dev, "Timeout, status 0x%08x\n", status);
-		reg_write(smbus, REG_SMSTA, status);
+	/* Peripheral timeout? */
+	if (status & SMSTA_MTO) {
+		dev_warn(smbus->dev, "Peripheral timeout, status 0x%08x\n", status);
 		return -ETIME;
 	}
 
+	/* Still stuck in a transaction? */
+	if (status & SMSTA_XIP) {
+		dev_warn(smbus->dev, "Bus stuck, status 0x%08x\n", status);
+		return -EIO;
+	}
+
+	/* Arbitration loss? */
+	if (status & SMSTA_MTA) {
+		dev_warn(smbus->dev, "Arbitration loss, status 0x%08x\n", status);
+		return -EBUSY;
+	}
+
+	/* Got NACK? */
+	if (status & SMSTA_MTN) {
+		dev_warn(smbus->dev, "NACK, status 0x%08x\n", status);
+		return -ENXIO;
+	}
+
 	/* Clear XEN */
 	reg_write(smbus, REG_SMSTA, SMSTA_XEN);
 
@@ -177,7 +221,8 @@ static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
 	struct pasemi_smbus *smbus = adapter->algo_data;
 	int ret, i;
 
-	pasemi_smb_clear(smbus);
+	if (pasemi_smb_clear(smbus))
+		return -EIO;
 
 	ret = 0;
 
@@ -200,7 +245,8 @@ static int pasemi_smb_xfer(struct i2c_adapter *adapter,
 	addr <<= 1;
 	read_flag = read_write == I2C_SMBUS_READ;
 
-	pasemi_smb_clear(smbus);
+	if (pasemi_smb_clear(smbus))
+		return -EIO;
 
 	switch (size) {
 	case I2C_SMBUS_QUICK:

-- 
2.34.1

Re: [PATCH 2/4] i2c: pasemi: Improve error recovery

[Andi Shyti]

Hi Sven,

On Sat, Feb 22, 2025 at 01:38:34PM +0000, Sven Peter via B4 Relay wrote:
> The hardware (supposedly) has a 25ms timeout for clock stretching
> and the driver uses 100ms which should be plenty.

Can we add this lines as a comment to the define you are adding?

> The error
> reocvery itself is however lacking.

...

> -static void pasemi_smb_clear(struct pasemi_smbus *smbus)
> +static int pasemi_smb_clear(struct pasemi_smbus *smbus)
>  {
>  	unsigned int status;
> +	int timeout = TRANSFER_TIMEOUT_MS;
>  
>  	status = reg_read(smbus, REG_SMSTA);
> +
> +	/* First wait for the bus to go idle */
> +	while ((status & (SMSTA_XIP | SMSTA_JAM)) && timeout--) {
> +		msleep(1);

Please, use usleep_range for 1 millisecond timeout.

> +		status = reg_read(smbus, REG_SMSTA);
> +	}

You could use here readx_poll_timeout() here.

> +
> +	if (timeout < 0) {
> +		dev_warn(smbus->dev, "Bus is still stuck (status 0x%08x)\n", status);

if it's an error, please use an error.

> +		return -EIO;
> +	}
> +
> +	/* If any badness happened or there is data in the FIFOs, reset the FIFOs */
> +	if ((status & (SMSTA_MRNE | SMSTA_JMD | SMSTA_MTO | SMSTA_TOM | SMSTA_MTN | SMSTA_MTA)) ||
> +		!(status & SMSTA_MTE))

Please, fixe the alignment here.

> +		pasemi_reset(smbus);
> +
> +	/* Clear the flags */
>  	reg_write(smbus, REG_SMSTA, status);
> +
> +	return 0;
>  }
>  
>  static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
>  {
> -	int timeout = 100;
> +	int timeout = TRANSFER_TIMEOUT_MS;
>  	unsigned int status;
>  
>  	if (smbus->use_irq) {
>  		reinit_completion(&smbus->irq_completion);
> -		reg_write(smbus, REG_IMASK, SMSTA_XEN | SMSTA_MTN);
> -		wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(100));
> +		/* XEN should be set when a transaction terminates, whether due to error or not */
> +		reg_write(smbus, REG_IMASK, SMSTA_XEN);
> +		wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(timeout));

what happens if the timeout expires?

>  		reg_write(smbus, REG_IMASK, 0);
>  		status = reg_read(smbus, REG_SMSTA);
>  	} else {

...

>  	struct pasemi_smbus *smbus = adapter->algo_data;
>  	int ret, i;
>  
> -	pasemi_smb_clear(smbus);
> +	if (pasemi_smb_clear(smbus))
> +		return -EIO;

Can we use

	ret = ...
	if (ret)
		return ret;

This way we return whatever comes from pasemi_smb_clear().

>  
>  	ret = 0;

This way we can remove this line, as well.

Andi

Re: [PATCH 2/4] i2c: pasemi: Improve error recovery

[Sven Peter]

Hi Andi,

Thanks for the review! Will send a v2 after -rc1 is out.

On Thu, Mar 20, 2025, at 01:17, Andi Shyti wrote:
> Hi Sven,
>
> On Sat, Feb 22, 2025 at 01:38:34PM +0000, Sven Peter via B4 Relay wrote:
>> The hardware (supposedly) has a 25ms timeout for clock stretching
>> and the driver uses 100ms which should be plenty.
>
> Can we add this lines as a comment to the define you are adding?

Sure.

>
>> The error
>> reocvery itself is however lacking.
>
> ...
>
>> -static void pasemi_smb_clear(struct pasemi_smbus *smbus)
>> +static int pasemi_smb_clear(struct pasemi_smbus *smbus)
>>  {
>>  	unsigned int status;
>> +	int timeout = TRANSFER_TIMEOUT_MS;
>>  
>>  	status = reg_read(smbus, REG_SMSTA);
>> +
>> +	/* First wait for the bus to go idle */
>> +	while ((status & (SMSTA_XIP | SMSTA_JAM)) && timeout--) {
>> +		msleep(1);
>
> Please, use usleep_range for 1 millisecond timeout.

Ack.

>
>> +		status = reg_read(smbus, REG_SMSTA);
>> +	}
>
> You could use here readx_poll_timeout() here.

Yup, that should work.

>
>> +
>> +	if (timeout < 0) {
>> +		dev_warn(smbus->dev, "Bus is still stuck (status 0x%08x)\n", status);
>
> if it's an error, please use an error.

Ack.

>
>> +		return -EIO;
>> +	}
>> +
>> +	/* If any badness happened or there is data in the FIFOs, reset the FIFOs */
>> +	if ((status & (SMSTA_MRNE | SMSTA_JMD | SMSTA_MTO | SMSTA_TOM | SMSTA_MTN | SMSTA_MTA)) ||
>> +		!(status & SMSTA_MTE))
>
> Please, fixe the alignment here.

Ok.

>
>> +		pasemi_reset(smbus);
>> +
>> +	/* Clear the flags */
>>  	reg_write(smbus, REG_SMSTA, status);
>> +
>> +	return 0;
>>  }
>>  
>>  static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
>>  {
>> -	int timeout = 100;
>> +	int timeout = TRANSFER_TIMEOUT_MS;
>>  	unsigned int status;
>>  
>>  	if (smbus->use_irq) {
>>  		reinit_completion(&smbus->irq_completion);
>> -		reg_write(smbus, REG_IMASK, SMSTA_XEN | SMSTA_MTN);
>> -		wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(100));
>> +		/* XEN should be set when a transaction terminates, whether due to error or not */
>> +		reg_write(smbus, REG_IMASK, SMSTA_XEN);
>> +		wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(timeout));
>
> what happens if the timeout expires?

I think that can only happen if the hardware is seriously broken because
it's always supposed to set XEN. I'll make sure to catch that case in v2
though and print a separate error message similar to how the polling case
below is taken care of right now.

>
>>  		reg_write(smbus, REG_IMASK, 0);
>>  		status = reg_read(smbus, REG_SMSTA);
>>  	} else {
>
> ...
>
>>  	struct pasemi_smbus *smbus = adapter->algo_data;
>>  	int ret, i;
>>  
>> -	pasemi_smb_clear(smbus);
>> +	if (pasemi_smb_clear(smbus))
>> +		return -EIO;
>
> Can we use
>
> 	ret = ...
> 	if (ret)
> 		return ret;
>
> This way we return whatever comes from pasemi_smb_clear().
>
>>  
>>  	ret = 0;
>
> This way we can remove this line, as well.

Sure, will do both for v2.



Thanks,


Sven

[PATCH 3/4] i2c: pasemi: Enable the unjam machine

[Sven Peter via B4 Relay]

From: Hector Martin <marcan@marcan.st>

The I2C bus can get stuck under some conditions (desync between
controller and device). The pasemi controllers include an unjam feature
that is enabled on reset, but was being disabled by the driver. Keep it
enabled by explicitly setting the UJM bit in the CTL register. This
should help recover the bus from certain conditions, which would
otherwise remain stuck forever.

Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
 drivers/i2c/busses/i2c-pasemi-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-pasemi-core.c b/drivers/i2c/busses/i2c-pasemi-core.c
index 770b86b92a10..8f0ba975172f 100644
--- a/drivers/i2c/busses/i2c-pasemi-core.c
+++ b/drivers/i2c/busses/i2c-pasemi-core.c
@@ -73,7 +73,7 @@ static inline int reg_read(struct pasemi_smbus *smbus, int reg)
 
 static void pasemi_reset(struct pasemi_smbus *smbus)
 {
-	u32 val = (CTL_MTR | CTL_MRR | (smbus->clk_div & CTL_CLK_M));
+	u32 val = (CTL_MTR | CTL_MRR | CTL_UJM | (smbus->clk_div & CTL_CLK_M));
 
 	if (smbus->hw_rev >= 6)
 		val |= CTL_EN;

-- 
2.34.1

[PATCH 4/4] i2c: pasemi: Log bus reset causes

[Sven Peter via B4 Relay]

From: Hector Martin <marcan@marcan.st>

This ensures we get all information we need to debug issues when users
forward us their logs.

Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
 drivers/i2c/busses/i2c-pasemi-core.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pasemi-core.c b/drivers/i2c/busses/i2c-pasemi-core.c
index 8f0ba975172f..ae0181a76470 100644
--- a/drivers/i2c/busses/i2c-pasemi-core.c
+++ b/drivers/i2c/busses/i2c-pasemi-core.c
@@ -21,6 +21,7 @@
 /* Register offsets */
 #define REG_MTXFIFO	0x00
 #define REG_MRXFIFO	0x04
+#define REG_XFSTA	0x0c
 #define REG_SMSTA	0x14
 #define REG_IMASK	0x18
 #define REG_CTL		0x1c
@@ -84,7 +85,7 @@ static void pasemi_reset(struct pasemi_smbus *smbus)
 
 static int pasemi_smb_clear(struct pasemi_smbus *smbus)
 {
-	unsigned int status;
+	unsigned int status, xfstatus;
 	int timeout = TRANSFER_TIMEOUT_MS;
 
 	status = reg_read(smbus, REG_SMSTA);
@@ -95,15 +96,21 @@ static int pasemi_smb_clear(struct pasemi_smbus *smbus)
 		status = reg_read(smbus, REG_SMSTA);
 	}
 
+	xfstatus = reg_read(smbus, REG_XFSTA);
+
 	if (timeout < 0) {
-		dev_warn(smbus->dev, "Bus is still stuck (status 0x%08x)\n", status);
+		dev_warn(smbus->dev, "Bus is still stuck (status 0x%08x xfstatus 0x%08x)\n",
+			 status, xfstatus);
 		return -EIO;
 	}
 
 	/* If any badness happened or there is data in the FIFOs, reset the FIFOs */
 	if ((status & (SMSTA_MRNE | SMSTA_JMD | SMSTA_MTO | SMSTA_TOM | SMSTA_MTN | SMSTA_MTA)) ||
-		!(status & SMSTA_MTE))
+		!(status & SMSTA_MTE)) {
+		dev_warn(smbus->dev, "Issuing reset due to status 0x%08x (xfstatus 0x%08x)\n",
+			 status, xfstatus);
 		pasemi_reset(smbus);
+	}
 
 	/* Clear the flags */
 	reg_write(smbus, REG_SMSTA, status);

-- 
2.34.1

Re: [PATCH 0/4] Apple/PASemi i2c error recovery fixes

[Alyssa Rosenzweig]

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>

Le Sat , Feb 22, 2025 at 01:38:32PM +0000, Sven Peter via B4 Relay a écrit :
> Hi,
> 
> This series adds a few fixes/improvements to the error recovery for
> Apple/PASemi i2c controllers.
> The patches have been in our downstream tree and were originally used
> to debug a rare glitch caused by clock strechting but are useful in
> general. We haven't seen the controller misbehave since adding these.
> 
> Best,
> 
> Sven
> 
> Signed-off-by: Sven Peter <sven@svenpeter.dev>
> ---
> Hector Martin (3):
>       i2c: pasemi: Improve error recovery
>       i2c: pasemi: Enable the unjam machine
>       i2c: pasemi: Log bus reset causes
> 
> Sven Peter (1):
>       i2c: pasemi: Add registers bits and switch to BIT()
> 
>  drivers/i2c/busses/i2c-pasemi-core.c | 121 ++++++++++++++++++++++++++---------
>  1 file changed, 92 insertions(+), 29 deletions(-)
> ---
> base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
> change-id: 20250220-pasemi-fixes-916cb77404ba
> 
> Best regards,
> -- 
> Sven Peter <sven@svenpeter.dev>
> 
> 

Re: [PATCH 0/4] Apple/PASemi i2c error recovery fixes

[Neal Gompa]

On Sat, Feb 22, 2025 at 8:38 AM Sven Peter via B4 Relay
<devnull+sven.svenpeter.dev@kernel.org> wrote:
>
> Hi,
>
> This series adds a few fixes/improvements to the error recovery for
> Apple/PASemi i2c controllers.
> The patches have been in our downstream tree and were originally used
> to debug a rare glitch caused by clock strechting but are useful in
> general. We haven't seen the controller misbehave since adding these.
>
> Best,
>
> Sven
>
> Signed-off-by: Sven Peter <sven@svenpeter.dev>
> ---
> Hector Martin (3):
>       i2c: pasemi: Improve error recovery
>       i2c: pasemi: Enable the unjam machine
>       i2c: pasemi: Log bus reset causes
>
> Sven Peter (1):
>       i2c: pasemi: Add registers bits and switch to BIT()
>
>  drivers/i2c/busses/i2c-pasemi-core.c | 121 ++++++++++++++++++++++++++---------
>  1 file changed, 92 insertions(+), 29 deletions(-)
> ---
> base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
> change-id: 20250220-pasemi-fixes-916cb77404ba
>
> Best regards,
> --
> Sven Peter <sven@svenpeter.dev>
>
>
>

LGTM.

Reviewed-by: Neal Gompa <neal@gompa.dev>



-- 
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