watchdog: da9062: Correct the timeout values [Klartext]

Quoted 6 lines

Thanks anyway, so now I know it must be
problem with my DA9061 chip.

@Adam
Where can it come from?
Can you give we a hint what to check?

I've spoken internally and have been informed that this is down to the fact that DA9061 runs only from an internal oscillator which may be slower. The indication is that the values for TWDSCALE describe the window where if a kick/ping occurs within that period then the watchdog is guaranteed *not* to timeout. The actual timeout would be at some point after the selected timeout period, assuming no ping/kick occurred.

Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s (tWDMAX) under specific operating conditions, so if the minimum 2s window was chosen (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a ping, is 2.5s, assuming the conditions matched those described.

If you have further questions it probably makes sense to contact Dialog/Renesas support as they will be able to provide more detailed info on this.

Resend with [Klartext] to turn off TLS encryption.

From: Adam Thomson
Sent: Monday, December 6, 2021 5:38 PM

Quoted 14 lines

Quoted 6 lines

Thanks anyway, so now I know it must be
problem with my DA9061 chip.

@Adam
Where can it come from?
Can you give we a hint what to check?

I've spoken internally and have been informed that this is down to the fact that DA9061 runs only from an internal oscillator which may be slower. The indication is that the values for TWDSCALE describe the window where if a kick/ping occurs within that period then the watchdog is guaranteed *not* to timeout. The actual timeout would be at some point after the selected timeout period, assuming no ping/kick occurred.

Quoted 7 lines

Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s (tWDMAX) under specific operating conditions, so if the minimum 2s window was chosen (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a ping, is 2.5s, assuming the conditions matched those described.

If you have further questions it probably makes sense to contact Dialog/Renesas support as they will be able to provide more detailed info on this.

So a DA9061 runs only from an internal oscillator, whereas a DA9062 can run on either an internal or an external oscillator. So this means that the DA9061 timeout values are differ from the DA9062 with an external oscillator not only on my device but on all DA9061 devices.

This are the values (in seconds) in comparison:

DA9062 (from driver): 0  2  4   8  16  32  65 131
DA9061 (measured):    0  3  6  12  25  51 102 204

=================================================
Difference: 0 +1 +2 +4 +9 +19 +37 +73

In my opinion, the differences in the higher values are very huge. If I expect that the watchdog triggers and I have to wait more than a minute for that to happen I ask myself is there something wrong.

@Andrej
I guess, you are using an external oscillator, aren't you?

@Adam
Is there a way to check in the driver which oscillator is in use?

@Maintainers
Is in the driver a need to distinguish between an external and an internal oscillator to get the timeout values more accurate?

Quoted 43 lines

From: Adam Thomson
Sent: Monday, December 6, 2021 5:38 PM

Quoted 14 lines

Quoted 6 lines

Thanks anyway, so now I know it must be
problem with my DA9061 chip.

@Adam
Where can it come from?
Can you give we a hint what to check?

I've spoken internally and have been informed that this is down to the fact that DA9061 runs only from an internal oscillator which may be slower. The indication is that the values for TWDSCALE describe the window where if a kick/ping occurs within that period then the watchdog is guaranteed *not* to timeout. The actual timeout would be at some point after the selected timeout period, assuming no ping/kick occurred.

Quoted 7 lines

Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s (tWDMAX) under specific operating conditions, so if the minimum 2s window was chosen (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a ping, is 2.5s, assuming the conditions matched those described.

If you have further questions it probably makes sense to contact Dialog/Renesas support as they will be able to provide more detailed info on this.

So a DA9061 runs only from an internal oscillator, whereas a DA9062 can run on either an internal or an external oscillator. So this means that the DA9061 timeout values are differ from the DA9062 with an external oscillator not only on my device but on all DA9061 devices.

This are the values (in seconds) in comparison:

DA9062 (from driver): 0  2  4   8  16  32  65 131
DA9061 (measured):    0  3  6  12  25  51 102 204

=================================================
Difference: 0 +1 +2 +4 +9 +19 +37 +73

In my opinion, the differences in the higher values are very huge. If I expect that the watchdog triggers and I have to wait more than a minute for that to happen I ask myself is there something wrong.

@Andrej
I guess, you are using an external oscillator, aren't you?

Quoted 7 lines

@Adam
Is there a way to check in the driver which oscillator is in use?

@Maintainers
Is in the driver a need to distinguish between an external and an internal oscillator to get the timeout values more accurate?

It would be very desirable to get timeout values more accurate. I would not want to dictate how to implement it, though. It could be automatically detected if that is possible, there could be a devicetree clock property providing the clock frequency, or maybe there is some other solution.

Guenter

Quoted 49 lines

Quoted 41 lines

Quoted 14 lines

Quoted 6 lines

Thanks anyway, so now I know it must be
problem with my DA9061 chip.

@Adam
Where can it come from?
Can you give we a hint what to check?

I've spoken internally and have been informed that this is down to the fact that DA9061 runs only from an internal oscillator which may be slower. The indication is that the values for TWDSCALE describe the window where if a kick/ping occurs within that period then the watchdog is guaranteed *not* to timeout. The actual timeout would be at some point after the selected timeout period, assuming no ping/kick occurred.

Quoted 7 lines

Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s (tWDMAX) under specific operating conditions, so if the minimum 2s window was chosen (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a ping, is 2.5s, assuming the conditions matched those described.

If you have further questions it probably makes sense to contact Dialog/Renesas support as they will be able to provide more detailed info on this.

So a DA9061 runs only from an internal oscillator, whereas a DA9062 can run on either an internal or an external oscillator. So this means that the DA9061 timeout values are differ from the DA9062 with an external oscillator not only on my device but on all DA9061 devices.

This are the values (in seconds) in comparison:

DA9062 (from driver): 0  2  4   8  16  32  65 131
DA9061 (measured):    0  3  6  12  25  51 102 204

=================================================
Difference: 0 +1 +2 +4 +9 +19 +37 +73

In my opinion, the differences in the higher values are very huge. If I expect that the watchdog triggers and I have to wait more than a minute for that to happen I ask myself is there something wrong.

@Andrej
I guess, you are using an external oscillator, aren't you?

Quoted 7 lines

@Adam
Is there a way to check in the driver which oscillator is in use?

@Maintainers
Is in the driver a need to distinguish between an external and an internal oscillator to get the timeout values more accurate?

Quoted 7 lines

It would be very desirable to get timeout values more accurate. I would not want to dictate how to implement it, though. It could be automatically detected if that is possible, there could be a devicetree clock property providing the clock frequency, or maybe there is some other solution.

Guenter

I am open for a good solution.
Meanwhile I measured the timeout values of my 8 available DA9061 watchdogs. I derived the following formula from the given formula at the data sheet and the clock divider of 2^16:

f = 2^(15+TWDSCALE) / t

Formula check with the external oscillator (32kHz) TWDSCALE=7 @ 131s:
f = 2^(15+7) / 131 = 32017Hz (=> should be OK)

The timeouts of my 8 watchdogs (9061-AA) with TWDSCALE=7:
t7 = 211s => 19878Hz
t7 = 197s => 21291Hz
t7 = 203s => 20662Hz
t7 = 204s => 20560Hz
t7 = 206s => 20361Hz
t7 = 198s => 21662Hz
t7 = 200s => 20972Hz

According to the data sheet the internal oscillator should run at 25kHz. The average frequency of my 8 devices is 20.6kHz. Maybe the data sheet Clock value is a max value. The timeout difference on my 8 devices are 14s. So the values vary from device to device, and maybe there is also a temperature component.

@Adam
Is there a way to check which oscillator is in use?
Is there a way to find the current oscillator frequency?
Are there any other ideas/solutions to get the timeout values more accurate?

A quick scan of the DA9062 datasheet shows that reg/field EN_32K/CRYSTAL will indicate the presence of a 32KHz crystal oscillator. Obviously on DA9061 that option isn't available.

I think the problem seems to lie around determining the internal oscillator's frequency. Datasheet references 25Mhz in Table 9 (Watchdog Electrical Characteristics), but that doesn't seem to tally with your timings and I don't see an obvious way in the regmap to calculate this at run time. *If* the oscillator frequency varies from part to part, or under different environmental conditions, then it's going to be tough to tie this down, and you wouldn't want to state a timeout value that's longer than reality.

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Thanks anyway, so now I know it must be
problem with my DA9061 chip.

@Adam
Where can it come from?
Can you give we a hint what to check?

I've spoken internally and have been informed that this is down to the fact that DA9061 runs only from an internal oscillator which may be slower. The indication is that the values for TWDSCALE describe the window where if a kick/ping occurs within that period then the watchdog is guaranteed *not* to timeout. The actual timeout would be at some point after the selected timeout period, assuming no ping/kick occurred.

Quoted 7 lines

Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s (tWDMAX) under specific operating conditions, so if the minimum 2s window was chosen (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a ping, is 2.5s, assuming the conditions matched those described.

If you have further questions it probably makes sense to contact Dialog/Renesas support as they will be able to provide more detailed info on this.

So a DA9061 runs only from an internal oscillator, whereas a DA9062 can run on either an internal or an external oscillator. So this means that the DA9061 timeout values are differ from the DA9062 with an external oscillator not only on my device but on all DA9061 devices.

This are the values (in seconds) in comparison:

DA9062 (from driver): 0  2  4   8  16  32  65 131
DA9061 (measured):    0  3  6  12  25  51 102 204

=================================================
Difference: 0 +1 +2 +4 +9 +19 +37 +73

In my opinion, the differences in the higher values are very huge. If I expect that the watchdog triggers and I have to wait more than a minute for that to happen I ask myself is there something wrong.

@Andrej
I guess, you are using an external oscillator, aren't you?

Quoted 7 lines

@Adam
Is there a way to check in the driver which oscillator is in use?

@Maintainers
Is in the driver a need to distinguish between an external and an internal oscillator to get the timeout values more accurate?

Quoted 7 lines

It would be very desirable to get timeout values more accurate. I would not want to dictate how to implement it, though. It could be automatically detected if that is possible, there could be a devicetree clock property providing the clock frequency, or maybe there is some other solution.

Guenter

I am open for a good solution.
Meanwhile I measured the timeout values of my 8 available DA9061 watchdogs. I derived the following formula from the given formula at the data sheet and the clock divider of 2^16:

f = 2^(15+TWDSCALE) / t

Formula check with the external oscillator (32kHz) TWDSCALE=7 @ 131s:
f = 2^(15+7) / 131 = 32017Hz (=> should be OK)

The timeouts of my 8 watchdogs (9061-AA) with TWDSCALE=7:
t7 = 211s => 19878Hz
t7 = 197s => 21291Hz
t7 = 203s => 20662Hz
t7 = 204s => 20560Hz
t7 = 206s => 20361Hz
t7 = 198s => 21662Hz
t7 = 200s => 20972Hz

According to the data sheet the internal oscillator should run at 25kHz. The average frequency of my 8 devices is 20.6kHz. Maybe the data sheet Clock value is a max value. The timeout difference on my 8 devices are 14s. So the values vary from device to device, and maybe there is also a temperature component.

Quoted 4 lines

@Adam
Is there a way to check which oscillator is in use?
Is there a way to find the current oscillator frequency?
Are there any other ideas/solutions to get the timeout values more accurate?

As I sent my E-Mail I didn't see your answer, so here it is:

Quoted 11 lines

A quick scan of the DA9062 datasheet shows that reg/field EN_32K/CRYSTAL will indicate the presence of a 32KHz crystal oscillator. Obviously on DA9061 that option isn't available.

I think the problem seems to lie around determining the internal oscillator's frequency. Datasheet references 25Mhz in Table 9 (Watchdog Electrical Characteristics), but that doesn't seem to tally with your timings and I don't see an obvious way in the regmap to calculate this at run time. *If* the oscillator frequency varies from part to part, or under different environmental conditions, then it's going to be tough to tie this down, and you wouldn't want to state a timeout value that's longer than reality.

@Adam
What do you think if I add also the timeout values for the internal oscillator?
Than the values would be:

t = 2^(15+TWDSCALE) / f

Internal 25kHz oscillator: 0 2 5 10 20 41 83 167

In comparison to the
external 32kHz oscillator: 0 2 4 8 16 32 65 131

So the difference to my measured values will decrease and it will improve the
current driver towards more accurate values.

Btw if I calculate the values with 32768Hz (the typical 32kHz oscillator), I get the
following values:
32768Hz oscillator: 0 2 4 8 16 32 64 128

I come to the conclusion that under normal condition (room temperature) the timeout values could be improved, but due to the used internal ring oscillator on the DA9061 chip under extreme conditions like automotive (125 degrees) the values come close to the DA9062 timeout values, if an external oscillator is used. In order not to trigger too early in extreme situations, the values must be left as they are. But I told Dialog to add a note in the data sheet explaining the deviation when the internal oscillator is used (DA9061).

Thanks for helping me and best regards
Christoph

Resend with [Klartext] to turn off TLS encryption.

From: Adam Thomson
Sent: Monday, December 6, 2021 5:38 PM

Quoted 14 lines

Quoted 6 lines

Thanks anyway, so now I know it must be
problem with my DA9061 chip.

@Adam
Where can it come from?
Can you give we a hint what to check?

I've spoken internally and have been informed that this is down to the fact that DA9061 runs only from an internal oscillator which may be slower. The indication is that the values for TWDSCALE describe the window where if a kick/ping occurs within that period then the watchdog is guaranteed *not* to timeout. The actual timeout would be at some point after the selected timeout period, assuming no ping/kick occurred.

Quoted 7 lines

Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s (tWDMAX) under specific operating conditions, so if the minimum 2s window was chosen (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a ping, is 2.5s, assuming the conditions matched those described.

If you have further questions it probably makes sense to contact Dialog/Renesas support as they will be able to provide more detailed info on this.

So a DA9061 runs only from an internal oscillator, whereas a DA9062 can run on either an internal or an external oscillator. So this means that the DA9061 timeout values are differ from the DA9062 with an external oscillator not only on my device but on all DA9061 devices.

This are the values (in seconds) in comparison:

DA9062 (from driver): 0  2  4   8  16  32  65 131
DA9061 (measured):    0  3  6  12  25  51 102 204

=================================================
Difference: 0 +1 +2 +4 +9 +19 +37 +73

In my opinion, the differences in the higher values are very huge. If I expect that the watchdog triggers and I have to wait more than a minute for that to happen I ask myself is there something wrong.

@Andrej
I guess, you are using an external oscillator, aren't you?

@Adam
Is there a way to check in the driver which oscillator is in use?

@Maintainers
Is in the driver a need to distinguish between an external and an internal oscillator to get the timeout values more accurate?

Best regards
Christoph

Quoted 2 lines

@Andrej
I guess, you are using an external oscillator, aren't you?

You are correct, we are using external oscillator (32,768KHz).

Resend with [Klartext] to turn off TLS encryption.

From: Adam Thomson
Sent: Monday, December 6, 2021 5:38 PM

Quoted 9 lines

Quoted 6 lines

Thanks anyway, so now I know it must be
problem with my DA9061 chip.

@Adam
Where can it come from?
Can you give we a hint what to check?

I've spoken internally and have been informed that this is down to the fact that DA9061 runs only from an internal oscillator which may be slower. The

indication

Quoted 1 line

is that the values for TWDSCALE describe the window where if a kick/ping

occurs

Quoted 1 line

within that period then the watchdog is guaranteed *not* to timeout. The

actual

Quoted 1 line

timeout would be at some point after the selected timeout period, assuming

no

Quoted 3 lines

ping/kick occurred.

Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s

(tWDMAX)

Quoted 5 lines

under specific operating conditions, so if the minimum 2s window was chosen (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a ping, is 2.5s, assuming the conditions matched those described.

If you have further questions it probably makes sense to contact

Dialog/Renesas

Quoted 1 line

support as they will be able to provide more detailed info on this.

So a DA9061 runs only from an internal oscillator, whereas a DA9062 can run on either an internal or an external oscillator. So this means that the DA9061 timeout values are differ from the DA9062 with an external oscillator not only on my device but on all DA9061 devices.

This are the values (in seconds) in comparison:

DA9062 (from driver): 0  2  4   8  16  32  65 131
DA9061 (measured):    0  3  6  12  25  51 102 204

=================================================
Difference: 0 +1 +2 +4 +9 +19 +37 +73

In my opinion, the differences in the higher values are very huge. If I expect that the watchdog triggers and I have to wait more than a minute for that to happen I ask myself is there something wrong.

@Andrej
I guess, you are using an external oscillator, aren't you?

@Adam
Is there a way to check in the driver which oscillator is in use?