| Message ID | 20211130134242.3516619-3-andrej.picej@norik.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/4] mfd: da9062: make register CONFIG_I writable | expand |
On 30. 11. 21 14:42, Andrej Picej wrote: > Document the watchdog timeout mode property. If this property is used > the user can select what happens on watchdog timeout. Set this property > to 1 to enable SHUTDOWN (the device resets), set it to 0 and the device > will go to POWERDOWN on watchdog timeout. > > Signed-off-by: Andrej Picej <andrej.picej@norik.com> > --- > Documentation/devicetree/bindings/watchdog/da9062-wdt.txt | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt > index 950e4fba8dbc..e3e6e56cee21 100644 > --- a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt > +++ b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt > @@ -10,6 +10,9 @@ Optional properties: > - dlg,use-sw-pm: Add this property to disable the watchdog during suspend. > Only use this option if you can't use the watchdog automatic suspend > function during a suspend (see register CONTROL_B). > +- dlg,wdt-sd: Set what happens on watchdog timeout. If this bit is set the > + watchdog timeout triggers SHUTDOWN, if cleared the watchdog triggers > + POWERDOWN. Can be 0 or 1. > > Example: DA9062 > > Changes in v2: - new patch, document new DT binding
On Guenter Roeck wrote: > > Document the watchdog timeout mode property. If this property is used > > the user can select what happens on watchdog timeout. Set this property > > to 1 to enable SHUTDOWN (the device resets), set it to 0 and the device > > will go to POWERDOWN on watchdog timeout. > > > > Signed-off-by: Andrej Picej <andrej.picej@norik.com> > > --- > > Documentation/devicetree/bindings/watchdog/da9062-wdt.txt | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt > b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt > > index 950e4fba8dbc..e3e6e56cee21 100644 > > --- a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt > > +++ b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt > > @@ -10,6 +10,9 @@ Optional properties: > > - dlg,use-sw-pm: Add this property to disable the watchdog during suspend. > > Only use this option if you can't use the watchdog automatic suspend > > function during a suspend (see register CONTROL_B). > > +- dlg,wdt-sd: Set what happens on watchdog timeout. If this bit is set the > > + watchdog timeout triggers SHUTDOWN, if cleared the watchdog triggers > > + POWERDOWN. Can be 0 or 1. > > > > Why does it need a value ? Why not just bool ? One argument might be that if the property isn't provided then the OTP configured value can persist without needing a FW change around this DT binding. My belief though is that the majority of users would have this property set to 0 by default in OTP, so a boolean would be OK I think here to enable watchdog shutdown.
On 11/30/21 8:11 AM, Adam Thomson wrote: > On Guenter Roeck wrote: > >>> Document the watchdog timeout mode property. If this property is used >>> the user can select what happens on watchdog timeout. Set this property >>> to 1 to enable SHUTDOWN (the device resets), set it to 0 and the device >>> will go to POWERDOWN on watchdog timeout. >>> >>> Signed-off-by: Andrej Picej <andrej.picej@norik.com> >>> --- >>> Documentation/devicetree/bindings/watchdog/da9062-wdt.txt | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt >> b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt >>> index 950e4fba8dbc..e3e6e56cee21 100644 >>> --- a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt >>> +++ b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt >>> @@ -10,6 +10,9 @@ Optional properties: >>> - dlg,use-sw-pm: Add this property to disable the watchdog during suspend. >>> Only use this option if you can't use the watchdog automatic suspend >>> function during a suspend (see register CONTROL_B). >>> +- dlg,wdt-sd: Set what happens on watchdog timeout. If this bit is set the >>> + watchdog timeout triggers SHUTDOWN, if cleared the watchdog triggers >>> + POWERDOWN. Can be 0 or 1. >>> >> >> Why does it need a value ? Why not just bool ? > > One argument might be that if the property isn't provided then the OTP > configured value can persist without needing a FW change around this DT binding. > > My belief though is that the majority of users would have this property set to 0 > by default in OTP, so a boolean would be OK I think here to enable watchdog > shutdown. > Sorry, you lost me. dlg,wdt-sd = <0>; is the current situation, and identical to not having the property in the first place. dlg,wdt-sd = <1>; is new. I don't see the difference to dlg,wdt-sd; vs. not having the property at all (which is, again, the current situation). Since it has to be backward compatible, dlg,wdt-sd = <0>; will always be identical to not having the property at all. I can not find a situation where an integer would have any benefits over a boolean. Guenter
On 30 November 2021 16:40, Guenter Roeck wrote: > >> Why does it need a value ? Why not just bool ? > > > > One argument might be that if the property isn't provided then the OTP > > configured value can persist without needing a FW change around this DT > binding. > > > > My belief though is that the majority of users would have this property set to 0 > > by default in OTP, so a boolean would be OK I think here to enable watchdog > > shutdown. > > > > Sorry, you lost me. > dlg,wdt-sd = <0>; > is the current situation, and identical to not having the property in > the first place. > dlg,wdt-sd = <1>; > is new. I don't see the difference to > dlg,wdt-sd; > vs. not having the property at all (which is, again, the current situation). > Since it has to be backward compatible, > dlg,wdt-sd = <0>; > will always be identical to not having the property at all. > I can not find a situation where an integer would have any benefits over a > boolean. So if you have a binary DT binding, it's either there or it isn't which implies the bit to be set to 0/1 in this case. If you have a binding which has a value, there can be 3 outcomes in this discussion: 1) Binding = 0, bit is set to 0 2) Binding = 1, bit is set to 1 3) Binding NOT present in DT, OTP default value in HW remains untouched Say a platform updates to a later kernel version, but sticks with existing DT FW (i.e. the new boolean binding isn't present in FW), then the following could happen: 1) OTP for DA9061/2 has this bit set to 1, system expectation is that watchdog triggers SHUTDOWN. 2) New driver checks existance of 'dlg,wdt-sd' but it's obviously not there so assumes the bit should be set to 0 and does so 3) When the watchdog fires, it will no longer trigger SHUTDOWN but instead POWER-DOWN due to binary handling of new boolean binding.
On 30. 11. 21 18:46, Adam Thomson wrote: > On 30 November 2021 16:40, Guenter Roeck wrote: > >>>> Why does it need a value ? Why not just bool ? >>> >>> One argument might be that if the property isn't provided then the OTP >>> configured value can persist without needing a FW change around this DT >> binding. >>> >>> My belief though is that the majority of users would have this property set to 0 >>> by default in OTP, so a boolean would be OK I think here to enable watchdog >>> shutdown. >>> >> >> Sorry, you lost me. >> dlg,wdt-sd = <0>; >> is the current situation, and identical to not having the property in >> the first place. >> dlg,wdt-sd = <1>; >> is new. I don't see the difference to >> dlg,wdt-sd; >> vs. not having the property at all (which is, again, the current situation). >> Since it has to be backward compatible, >> dlg,wdt-sd = <0>; >> will always be identical to not having the property at all. >> I can not find a situation where an integer would have any benefits over a >> boolean. > > So if you have a binary DT binding, it's either there or it isn't which implies > the bit to be set to 0/1 in this case. If you have a binding which has a value, > there can be 3 outcomes in this discussion: > > 1) Binding = 0, bit is set to 0 > 2) Binding = 1, bit is set to 1 > 3) Binding NOT present in DT, OTP default value in HW remains untouched > > Say a platform updates to a later kernel version, but sticks with existing DT > FW (i.e. the new boolean binding isn't present in FW), then the following could > happen: > > 1) OTP for DA9061/2 has this bit set to 1, system expectation is that watchdog > triggers SHUTDOWN. > 2) New driver checks existance of 'dlg,wdt-sd' but it's obviously not there so > assumes the bit should be set to 0 and does so > 3) When the watchdog fires, it will no longer trigger SHUTDOWN but instead > POWER-DOWN due to binary handling of new boolean binding. > This was my thinking exactly. I also first thought about boolean value, but I then moved to the integer value of 0 or 1 after checking the OTP default for this bit. The da9062 I'm working with has the bit set to 1 by default.
On 11/30/21 10:42 PM, Andrej Picej wrote: > > On 30. 11. 21 18:46, Adam Thomson wrote: >> On 30 November 2021 16:40, Guenter Roeck wrote: >> >>>>> Why does it need a value ? Why not just bool ? >>>> >>>> One argument might be that if the property isn't provided then the OTP >>>> configured value can persist without needing a FW change around this DT >>> binding. >>>> >>>> My belief though is that the majority of users would have this property set to 0 >>>> by default in OTP, so a boolean would be OK I think here to enable watchdog >>>> shutdown. >>>> >>> >>> Sorry, you lost me. >>> dlg,wdt-sd = <0>; >>> is the current situation, and identical to not having the property in >>> the first place. >>> dlg,wdt-sd = <1>; >>> is new. I don't see the difference to >>> dlg,wdt-sd; >>> vs. not having the property at all (which is, again, the current situation). >>> Since it has to be backward compatible, >>> dlg,wdt-sd = <0>; >>> will always be identical to not having the property at all. >>> I can not find a situation where an integer would have any benefits over a >>> boolean. >> >> So if you have a binary DT binding, it's either there or it isn't which implies >> the bit to be set to 0/1 in this case. If you have a binding which has a value, >> there can be 3 outcomes in this discussion: >> >> 1) Binding = 0, bit is set to 0 >> 2) Binding = 1, bit is set to 1 >> 3) Binding NOT present in DT, OTP default value in HW remains untouched >> >> Say a platform updates to a later kernel version, but sticks with existing DT >> FW (i.e. the new boolean binding isn't present in FW), then the following could >> happen: >> >> 1) OTP for DA9061/2 has this bit set to 1, system expectation is that watchdog >> triggers SHUTDOWN. >> 2) New driver checks existance of 'dlg,wdt-sd' but it's obviously not there so >> assumes the bit should be set to 0 and does so >> 3) When the watchdog fires, it will no longer trigger SHUTDOWN but instead >> POWER-DOWN due to binary handling of new boolean binding. >> > > This was my thinking exactly. I also first thought about boolean value, but I then moved to the integer value of 0 or 1 after checking the OTP default for this bit. The da9062 I'm working with has the bit set to 1 by default. That needs to be be documented. Guenter
On 1. 12. 21 08:01, Guenter Roeck wrote: > On 11/30/21 10:42 PM, Andrej Picej wrote: >> >> On 30. 11. 21 18:46, Adam Thomson wrote: >>> On 30 November 2021 16:40, Guenter Roeck wrote: >>> >>>>>> Why does it need a value ? Why not just bool ? >>>>> >>>>> One argument might be that if the property isn't provided then the OTP >>>>> configured value can persist without needing a FW change around >>>>> this DT >>>> binding. >>>>> >>>>> My belief though is that the majority of users would have this >>>>> property set to 0 >>>>> by default in OTP, so a boolean would be OK I think here to enable >>>>> watchdog >>>>> shutdown. >>>>> >>>> >>>> Sorry, you lost me. >>>> dlg,wdt-sd = <0>; >>>> is the current situation, and identical to not having the property in >>>> the first place. >>>> dlg,wdt-sd = <1>; >>>> is new. I don't see the difference to >>>> dlg,wdt-sd; >>>> vs. not having the property at all (which is, again, the current >>>> situation). >>>> Since it has to be backward compatible, >>>> dlg,wdt-sd = <0>; >>>> will always be identical to not having the property at all. >>>> I can not find a situation where an integer would have any benefits >>>> over a >>>> boolean. >>> >>> So if you have a binary DT binding, it's either there or it isn't >>> which implies >>> the bit to be set to 0/1 in this case. If you have a binding which >>> has a value, >>> there can be 3 outcomes in this discussion: >>> >>> 1) Binding = 0, bit is set to 0 >>> 2) Binding = 1, bit is set to 1 >>> 3) Binding NOT present in DT, OTP default value in HW remains >>> untouched >>> >>> Say a platform updates to a later kernel version, but sticks with >>> existing DT >>> FW (i.e. the new boolean binding isn't present in FW), then the >>> following could >>> happen: >>> >>> 1) OTP for DA9061/2 has this bit set to 1, system expectation is >>> that watchdog >>> triggers SHUTDOWN. >>> 2) New driver checks existance of 'dlg,wdt-sd' but it's obviously >>> not there so >>> assumes the bit should be set to 0 and does so >>> 3) When the watchdog fires, it will no longer trigger SHUTDOWN but >>> instead >>> POWER-DOWN due to binary handling of new boolean binding. >>> >> >> This was my thinking exactly. I also first thought about boolean >> value, but I then moved to the integer value of 0 or 1 after checking >> the OTP default for this bit. The da9062 I'm working with has the bit >> set to 1 by default. > > That needs to be be documented. > > Guenter Ok, I will add a note about the default value and how it is defined by OTP. Will submit a v3. Thanks for review. BR, Andrej
diff --git a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt index 950e4fba8dbc..e3e6e56cee21 100644 --- a/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt +++ b/Documentation/devicetree/bindings/watchdog/da9062-wdt.txt @@ -10,6 +10,9 @@ Optional properties: - dlg,use-sw-pm: Add this property to disable the watchdog during suspend. Only use this option if you can't use the watchdog automatic suspend function during a suspend (see register CONTROL_B). +- dlg,wdt-sd: Set what happens on watchdog timeout. If this bit is set the + watchdog timeout triggers SHUTDOWN, if cleared the watchdog triggers + POWERDOWN. Can be 0 or 1. Example: DA9062
Document the watchdog timeout mode property. If this property is used the user can select what happens on watchdog timeout. Set this property to 1 to enable SHUTDOWN (the device resets), set it to 0 and the device will go to POWERDOWN on watchdog timeout. Signed-off-by: Andrej Picej <andrej.picej@norik.com> --- Documentation/devicetree/bindings/watchdog/da9062-wdt.txt | 3 +++ 1 file changed, 3 insertions(+)