[v4,01/18] dt-bindings: power: battery: add constant-charge-current property

Message ID 20170315105537.22349-2-quentin.schulz@free-electrons.com
State New
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Series
  • [v4,01/18] dt-bindings: power: battery: add constant-charge-current property
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Commit Message

Quentin Schulz March 15, 2017, 10:55 a.m.
This adds the constant-charge-current property to the list of optional
properties of the battery.

The constant charge current is critical for batteries as they can't
handle all charge currents.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

Acked-by: Rob Herring <robh@kernel.org>

---

v4:
 - switch from constant-charge-current-microamp to constant-charge-microamp,

added in v3

 Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++
 1 file changed, 2 insertions(+)

-- 
2.9.3

Comments

Liam Breck March 15, 2017, 10:45 p.m. | #1
On Wed, Mar 15, 2017 at 6:10 AM, Quentin Schulz
<quentin.schulz@free-electrons.com> wrote:
> Hi Liam,

>

> On 15/03/2017 13:08, Liam Breck wrote:

>> I dropped most of the CCs, pls re-add anyone essential. Use Cc lines

>> in patch description to direct a patch to interested parties and

>> relevant lists. I don't want to see all 19 patches in this series.

>>

>> On Wed, Mar 15, 2017 at 3:55 AM, Quentin Schulz

>> <quentin.schulz@free-electrons.com> wrote:

>>> This adds the constant-charge-current property to the list of optional

>>> properties of the battery.

>>>

>>> The constant charge current is critical for batteries as they can't

>>> handle all charge currents.

>>>

>>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

>>> Acked-by: Rob Herring <robh@kernel.org>

>>> ---

>>>

>>> v4:

>>>  - switch from constant-charge-current-microamp to constant-charge-microamp,

>>

>> Must be constant-charge-current-microamp for the reasons discussed in

>> battery.txt - consistency with sysfs names.

>>

>

> Hum. Just nitpicking, but I disagree with the use of 'must'. IIRC there

> is nothing in the code that would require the property to be named after

> a property from the enum power_supply_property.

>

> I would say that you _want_ it to be named like that because it

> underlines the relation between the DT property and the actual impacted

> property in the power supply subsystem. I'm fine with this reason but in

> the end, the maintainer's opinion prevails (if (s)he does not want it,

> (s)he will not take it). So, basically, I actually don't mind either

> option and I see arguments on each side.

>

> So, just waiting for maintainer's opinion to make the final version of

> this patch.


But one should explain one's reasoning to the maintainer if he missed it :-)

And the docs for power_supply_get_battery_info() recommend naming
alignment with power_supply_property.


>> Also applies to power_supply_core.c patch.

>>

>> Rob: enum power_supply_property also lists constant-charge-voltage,

>> hence the -current

>>

>>

>>> added in v3

>>>

>>>  Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++

>>>  1 file changed, 2 insertions(+)

>>>

>>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt

>>> index 0278617..9594e1e 100644

>>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt

>>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt

>>> @@ -7,6 +7,7 @@ Optional Properties:

>>>   - voltage-min-design-microvolt: drained battery voltage

>>>   - energy-full-design-microwatt-hours: battery design energy

>>>   - charge-full-design-microamp-hours: battery design capacity

>>> + - constant-charge-microamp: battery constant charge current

>>>

>>>  Because drivers surface properties in sysfs using names derived

>>>  from enum power_supply_property, e.g.

>>> @@ -30,6 +31,7 @@ Example:

>>>                 voltage-min-design-microvolt = <3200000>;

>>>                 energy-full-design-microwatt-hours = <5290000>;

>>>                 charge-full-design-microamp-hours = <1430000>;

>>> +               constant-charge-microamp = <300000>;

>>>         };

>>>

>>>         charger: charger@11 {

>>> --

>>> 2.9.3

>>>

>

> --

> Quentin Schulz, Free Electrons

> Embedded Linux and Kernel engineering

> http://free-electrons.com
Liam Breck March 16, 2017, 6:27 a.m. | #2
Hi Rob,

On Wed, Mar 15, 2017 at 6:10 AM, Quentin Schulz
<quentin.schulz@free-electrons.com> wrote:
> Hi Liam,

>

> On 15/03/2017 13:08, Liam Breck wrote:

>> I dropped most of the CCs, pls re-add anyone essential. Use Cc lines

>> in patch description to direct a patch to interested parties and

>> relevant lists. I don't want to see all 19 patches in this series.

>>

>> On Wed, Mar 15, 2017 at 3:55 AM, Quentin Schulz

>> <quentin.schulz@free-electrons.com> wrote:

>>> This adds the constant-charge-current property to the list of optional

>>> properties of the battery.

>>>

>>> The constant charge current is critical for batteries as they can't

>>> handle all charge currents.

>>>

>>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

>>> Acked-by: Rob Herring <robh@kernel.org>

>>> ---

>>>

>>> v4:

>>>  - switch from constant-charge-current-microamp to constant-charge-microamp,


Sebastian is on record supporting name alignment between DT:battery
properties and enum power_supply_property.

Could you OK a change back to constant-charge-current-microamp in this patch?

Note that the following could appear in DT:battery in future:

constant-charge-current-microamp
constant-charge-current-max-microamp
constant-charge-voltage-microvolt
constant-charge-voltage-max-microvolt

Thanks!

>> Must be constant-charge-current-microamp for the reasons discussed in

>> battery.txt - consistency with sysfs names.

>>

>

> Hum. Just nitpicking, but I disagree with the use of 'must'. IIRC there

> is nothing in the code that would require the property to be named after

> a property from the enum power_supply_property.

>

> I would say that you _want_ it to be named like that because it

> underlines the relation between the DT property and the actual impacted

> property in the power supply subsystem. I'm fine with this reason but in

> the end, the maintainer's opinion prevails (if (s)he does not want it,

> (s)he will not take it). So, basically, I actually don't mind either

> option and I see arguments on each side.

>

> So, just waiting for maintainer's opinion to make the final version of

> this patch.

>

> Thanks,

> Quentin

>

>> Also applies to power_supply_core.c patch.

>>

>> Rob: enum power_supply_property also lists constant-charge-voltage,

>> hence the -current

>>

>>

>>> added in v3

>>>

>>>  Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++

>>>  1 file changed, 2 insertions(+)

>>>

>>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt

>>> index 0278617..9594e1e 100644

>>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt

>>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt

>>> @@ -7,6 +7,7 @@ Optional Properties:

>>>   - voltage-min-design-microvolt: drained battery voltage

>>>   - energy-full-design-microwatt-hours: battery design energy

>>>   - charge-full-design-microamp-hours: battery design capacity

>>> + - constant-charge-microamp: battery constant charge current

>>>

>>>  Because drivers surface properties in sysfs using names derived

>>>  from enum power_supply_property, e.g.

>>> @@ -30,6 +31,7 @@ Example:

>>>                 voltage-min-design-microvolt = <3200000>;

>>>                 energy-full-design-microwatt-hours = <5290000>;

>>>                 charge-full-design-microamp-hours = <1430000>;

>>> +               constant-charge-microamp = <300000>;

>>>         };

>>>

>>>         charger: charger@11 {

>>> --

>>> 2.9.3

>>>

>

> --

> Quentin Schulz, Free Electrons

> Embedded Linux and Kernel engineering

> http://free-electrons.com
Liam Breck March 16, 2017, 7:42 a.m. | #3
On Thu, Mar 16, 2017 at 12:03 AM, Quentin Schulz
<quentin.schulz@free-electrons.com> wrote:
> Hi Liam,

>

> On 16/03/2017 07:27, Liam Breck wrote:

>> Hi Rob,

>>

>> On Wed, Mar 15, 2017 at 6:10 AM, Quentin Schulz

>> <quentin.schulz@free-electrons.com> wrote:

>>> Hi Liam,

>>>

>>> On 15/03/2017 13:08, Liam Breck wrote:

>>>> I dropped most of the CCs, pls re-add anyone essential. Use Cc lines

>>>> in patch description to direct a patch to interested parties and

>>>> relevant lists. I don't want to see all 19 patches in this series.

>>>>

>>>> On Wed, Mar 15, 2017 at 3:55 AM, Quentin Schulz

>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>> This adds the constant-charge-current property to the list of optional

>>>>> properties of the battery.

>>>>>

>>>>> The constant charge current is critical for batteries as they can't

>>>>> handle all charge currents.

>>>>>

>>>>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

>>>>> Acked-by: Rob Herring <robh@kernel.org>

>>>>> ---

>>>>>

>>>>> v4:

>>>>>  - switch from constant-charge-current-microamp to constant-charge-microamp,

>>

>> Sebastian is on record supporting name alignment between DT:battery

>> properties and enum power_supply_property.

>>

>> Could you OK a change back to constant-charge-current-microamp in this patch?

>>

>> Note that the following could appear in DT:battery in future:

>>

>> constant-charge-current-microamp

>> constant-charge-current-max-microamp

>

> OK. I am actually setting max constant charge current and constant

> current charge with the same DT property so I might need to adapt my

> patches.


I suspect you should set battery:*-current-max with DT, as -current is
"programmed by charger" so seems to be a stat, not a fixed
characteristic.

You may program your charger's -current with the battery's
-current-max, of course.

Note that your charger also has a -current-max characteristic, likely
different than your battery. You may not need that in DT tho.

>> constant-charge-voltage-microvolt

>> constant-charge-voltage-max-microvolt

>>

>> Thanks!

>>

>>>> Must be constant-charge-current-microamp for the reasons discussed in

>>>> battery.txt - consistency with sysfs names.

>>>>

>>>

>>> Hum. Just nitpicking, but I disagree with the use of 'must'. IIRC there

>>> is nothing in the code that would require the property to be named after

>>> a property from the enum power_supply_property.

>>>

>>> I would say that you _want_ it to be named like that because it

>>> underlines the relation between the DT property and the actual impacted

>>> property in the power supply subsystem. I'm fine with this reason but in

>>> the end, the maintainer's opinion prevails (if (s)he does not want it,

>>> (s)he will not take it). So, basically, I actually don't mind either

>>> option and I see arguments on each side.

>>>

>>> So, just waiting for maintainer's opinion to make the final version of

>>> this patch.

>>>

>>> Thanks,

>>> Quentin

>>>

>>>> Also applies to power_supply_core.c patch.

>>>>

>>>> Rob: enum power_supply_property also lists constant-charge-voltage,

>>>> hence the -current

>>>>

>>>>

>>>>> added in v3

>>>>>

>>>>>  Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++

>>>>>  1 file changed, 2 insertions(+)

>>>>>

>>>>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>> index 0278617..9594e1e 100644

>>>>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>> @@ -7,6 +7,7 @@ Optional Properties:

>>>>>   - voltage-min-design-microvolt: drained battery voltage

>>>>>   - energy-full-design-microwatt-hours: battery design energy

>>>>>   - charge-full-design-microamp-hours: battery design capacity

>>>>> + - constant-charge-microamp: battery constant charge current

>>>>>

>>>>>  Because drivers surface properties in sysfs using names derived

>>>>>  from enum power_supply_property, e.g.

>>>>> @@ -30,6 +31,7 @@ Example:

>>>>>                 voltage-min-design-microvolt = <3200000>;

>>>>>                 energy-full-design-microwatt-hours = <5290000>;

>>>>>                 charge-full-design-microamp-hours = <1430000>;

>>>>> +               constant-charge-microamp = <300000>;

>>>>>         };

>>>>>

>>>>>         charger: charger@11 {

>>>>> --

>>>>> 2.9.3

>>>>>

>>>

>>> --

>>> Quentin Schulz, Free Electrons

>>> Embedded Linux and Kernel engineering

>>> http://free-electrons.com

>

> --

> Quentin Schulz, Free Electrons

> Embedded Linux and Kernel engineering

> http://free-electrons.com
Liam Breck March 29, 2017, 6:55 a.m. | #4
Hi Quentin,

On Thu, Mar 16, 2017 at 12:42 AM, Liam Breck <liam@networkimprov.net> wrote:
> On Thu, Mar 16, 2017 at 12:03 AM, Quentin Schulz

> <quentin.schulz@free-electrons.com> wrote:

>> Hi Liam,

>>

>> On 16/03/2017 07:27, Liam Breck wrote:

>>> Hi Rob,

>>>

>>> On Wed, Mar 15, 2017 at 6:10 AM, Quentin Schulz

>>> <quentin.schulz@free-electrons.com> wrote:

>>>> Hi Liam,

>>>>

>>>> On 15/03/2017 13:08, Liam Breck wrote:

>>>>> I dropped most of the CCs, pls re-add anyone essential. Use Cc lines

>>>>> in patch description to direct a patch to interested parties and

>>>>> relevant lists. I don't want to see all 19 patches in this series.

>>>>>

>>>>> On Wed, Mar 15, 2017 at 3:55 AM, Quentin Schulz

>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>> This adds the constant-charge-current property to the list of optional

>>>>>> properties of the battery.

>>>>>>

>>>>>> The constant charge current is critical for batteries as they can't

>>>>>> handle all charge currents.

>>>>>>

>>>>>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

>>>>>> Acked-by: Rob Herring <robh@kernel.org>

>>>>>> ---

>>>>>>

>>>>>> v4:

>>>>>>  - switch from constant-charge-current-microamp to constant-charge-microamp,

>>>

>>> Sebastian is on record supporting name alignment between DT:battery

>>> properties and enum power_supply_property.

>>>

>>> Could you OK a change back to constant-charge-current-microamp in this patch?

>>>

>>> Note that the following could appear in DT:battery in future:

>>>

>>> constant-charge-current-microamp

>>> constant-charge-current-max-microamp

>>

>> OK. I am actually setting max constant charge current and constant

>> current charge with the same DT property so I might need to adapt my

>> patches.

>

> I suspect you should set battery:*-current-max with DT, as -current is

> "programmed by charger" so seems to be a stat, not a fixed

> characteristic.


Did you resolve this issue?

Rob & Sebastian want me to merge all items for
bindings/power/supply/battery.txt. If I do that I'll also roll up
their counterparts in power_supply_core.c and submit a patchset for
those two files.

> You may program your charger's -current with the battery's

> -current-max, of course.

>

> Note that your charger also has a -current-max characteristic, likely

> different than your battery. You may not need that in DT tho.

>

>>> constant-charge-voltage-microvolt

>>> constant-charge-voltage-max-microvolt

>>>

>>> Thanks!

>>>

>>>>> Must be constant-charge-current-microamp for the reasons discussed in

>>>>> battery.txt - consistency with sysfs names.

>>>>>

>>>>

>>>> Hum. Just nitpicking, but I disagree with the use of 'must'. IIRC there

>>>> is nothing in the code that would require the property to be named after

>>>> a property from the enum power_supply_property.

>>>>

>>>> I would say that you _want_ it to be named like that because it

>>>> underlines the relation between the DT property and the actual impacted

>>>> property in the power supply subsystem. I'm fine with this reason but in

>>>> the end, the maintainer's opinion prevails (if (s)he does not want it,

>>>> (s)he will not take it). So, basically, I actually don't mind either

>>>> option and I see arguments on each side.

>>>>

>>>> So, just waiting for maintainer's opinion to make the final version of

>>>> this patch.

>>>>

>>>> Thanks,

>>>> Quentin

>>>>

>>>>> Also applies to power_supply_core.c patch.

>>>>>

>>>>> Rob: enum power_supply_property also lists constant-charge-voltage,

>>>>> hence the -current

>>>>>

>>>>>

>>>>>> added in v3

>>>>>>

>>>>>>  Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++

>>>>>>  1 file changed, 2 insertions(+)

>>>>>>

>>>>>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>> index 0278617..9594e1e 100644

>>>>>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>> @@ -7,6 +7,7 @@ Optional Properties:

>>>>>>   - voltage-min-design-microvolt: drained battery voltage

>>>>>>   - energy-full-design-microwatt-hours: battery design energy

>>>>>>   - charge-full-design-microamp-hours: battery design capacity

>>>>>> + - constant-charge-microamp: battery constant charge current

>>>>>>

>>>>>>  Because drivers surface properties in sysfs using names derived

>>>>>>  from enum power_supply_property, e.g.

>>>>>> @@ -30,6 +31,7 @@ Example:

>>>>>>                 voltage-min-design-microvolt = <3200000>;

>>>>>>                 energy-full-design-microwatt-hours = <5290000>;

>>>>>>                 charge-full-design-microamp-hours = <1430000>;

>>>>>> +               constant-charge-microamp = <300000>;

>>>>>>         };

>>>>>>

>>>>>>         charger: charger@11 {

>>>>>> --

>>>>>> 2.9.3

>>>>>>

>>>>

>>>> --

>>>> Quentin Schulz, Free Electrons

>>>> Embedded Linux and Kernel engineering

>>>> http://free-electrons.com

>>

>> --

>> Quentin Schulz, Free Electrons

>> Embedded Linux and Kernel engineering

>> http://free-electrons.com
Liam Breck March 29, 2017, 7:39 a.m. | #5
On Wed, Mar 29, 2017 at 12:09 AM, Quentin Schulz
<quentin.schulz@free-electrons.com> wrote:
> Hi Liam,

>

> On 29/03/2017 08:55, Liam Breck wrote:

>> Hi Quentin,

>>

>> On Thu, Mar 16, 2017 at 12:42 AM, Liam Breck <liam@networkimprov.net> wrote:

>>> On Thu, Mar 16, 2017 at 12:03 AM, Quentin Schulz

>>> <quentin.schulz@free-electrons.com> wrote:

>>>> Hi Liam,

>>>>

>>>> On 16/03/2017 07:27, Liam Breck wrote:

>>>>> Hi Rob,

>>>>>

>>>>> On Wed, Mar 15, 2017 at 6:10 AM, Quentin Schulz

>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>> Hi Liam,

>>>>>>

>>>>>> On 15/03/2017 13:08, Liam Breck wrote:

>>>>>>> I dropped most of the CCs, pls re-add anyone essential. Use Cc lines

>>>>>>> in patch description to direct a patch to interested parties and

>>>>>>> relevant lists. I don't want to see all 19 patches in this series.

>>>>>>>

>>>>>>> On Wed, Mar 15, 2017 at 3:55 AM, Quentin Schulz

>>>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>>>> This adds the constant-charge-current property to the list of optional

>>>>>>>> properties of the battery.

>>>>>>>>

>>>>>>>> The constant charge current is critical for batteries as they can't

>>>>>>>> handle all charge currents.

>>>>>>>>

>>>>>>>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

>>>>>>>> Acked-by: Rob Herring <robh@kernel.org>

>>>>>>>> ---

>>>>>>>>

>>>>>>>> v4:

>>>>>>>>  - switch from constant-charge-current-microamp to constant-charge-microamp,

>>>>>

>>>>> Sebastian is on record supporting name alignment between DT:battery

>>>>> properties and enum power_supply_property.

>>>>>

>>>>> Could you OK a change back to constant-charge-current-microamp in this patch?

>>>>>

>>>>> Note that the following could appear in DT:battery in future:

>>>>>

>>>>> constant-charge-current-microamp

>>>>> constant-charge-current-max-microamp

>>>>

>>>> OK. I am actually setting max constant charge current and constant

>>>> current charge with the same DT property so I might need to adapt my

>>>> patches.

>>>

>>> I suspect you should set battery:*-current-max with DT, as -current is

>>> "programmed by charger" so seems to be a stat, not a fixed

>>> characteristic.

>>

>> Did you resolve this issue?

>>

>

> Sorry, completely missed your first mail.

>

> Constant charge current is actually what I set in the PMIC. The maximum

> constant charge current is completely PMIC-agnostic in my driver as it

> is used to tell the user that (s)he shouldn't really have a constant

> charge current over the maximum limit as the battery might not be able

> to handle such high current.

>

> What I suggest is to have both properties in DT. I'll set the maximum as

> I do today and we can give the user the ability to set a "default"

> constant charge current (below maximum constant charge current) in the

> DT. Maybe we do not want to recharge your battery with the maximum value

> by default?


The scope here is just static battery characteristics. For the battery
node, I think constant-charge-current-max-microamp is the relevant
term. If we added both properties, one would be an alias for the
other, which doesn't seem useful.

The pmic can report both independently of the battery characteristic,
and take a driver-specific DT property for
constant-charge-current-microamp which it applies if less than the
battery's -max setting. Or you could set that in userspace via
/sys/class.../constant_charge_current. The charger's -max value would
be a characteristic of its regulator.

Or am I missing something...?

>> Rob & Sebastian want me to merge all items for

>> bindings/power/supply/battery.txt. If I do that I'll also roll up

>> their counterparts in power_supply_core.c and submit a patchset for

>> those two files.

>>

>

> I guess that adding the two properties make sense, don't you think?

>

> Also, could you Cc me on your next version of your patches? So I know

> when to rebase and slightly rework my patches once your patch series is

> merged.


Surely.

> Thanks,

> Quentin

>

>>> You may program your charger's -current with the battery's

>>> -current-max, of course.

>>>

>>> Note that your charger also has a -current-max characteristic, likely

>>> different than your battery. You may not need that in DT tho.

>>>

>>>>> constant-charge-voltage-microvolt

>>>>> constant-charge-voltage-max-microvolt

>>>>>

>>>>> Thanks!

>>>>>

>>>>>>> Must be constant-charge-current-microamp for the reasons discussed in

>>>>>>> battery.txt - consistency with sysfs names.

>>>>>>>

>>>>>>

>>>>>> Hum. Just nitpicking, but I disagree with the use of 'must'. IIRC there

>>>>>> is nothing in the code that would require the property to be named after

>>>>>> a property from the enum power_supply_property.

>>>>>>

>>>>>> I would say that you _want_ it to be named like that because it

>>>>>> underlines the relation between the DT property and the actual impacted

>>>>>> property in the power supply subsystem. I'm fine with this reason but in

>>>>>> the end, the maintainer's opinion prevails (if (s)he does not want it,

>>>>>> (s)he will not take it). So, basically, I actually don't mind either

>>>>>> option and I see arguments on each side.

>>>>>>

>>>>>> So, just waiting for maintainer's opinion to make the final version of

>>>>>> this patch.

>>>>>>

>>>>>> Thanks,

>>>>>> Quentin

>>>>>>

>>>>>>> Also applies to power_supply_core.c patch.

>>>>>>>

>>>>>>> Rob: enum power_supply_property also lists constant-charge-voltage,

>>>>>>> hence the -current

>>>>>>>

>>>>>>>

>>>>>>>> added in v3

>>>>>>>>

>>>>>>>>  Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++

>>>>>>>>  1 file changed, 2 insertions(+)

>>>>>>>>

>>>>>>>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>> index 0278617..9594e1e 100644

>>>>>>>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>> @@ -7,6 +7,7 @@ Optional Properties:

>>>>>>>>   - voltage-min-design-microvolt: drained battery voltage

>>>>>>>>   - energy-full-design-microwatt-hours: battery design energy

>>>>>>>>   - charge-full-design-microamp-hours: battery design capacity

>>>>>>>> + - constant-charge-microamp: battery constant charge current

>>>>>>>>

>>>>>>>>  Because drivers surface properties in sysfs using names derived

>>>>>>>>  from enum power_supply_property, e.g.

>>>>>>>> @@ -30,6 +31,7 @@ Example:

>>>>>>>>                 voltage-min-design-microvolt = <3200000>;

>>>>>>>>                 energy-full-design-microwatt-hours = <5290000>;

>>>>>>>>                 charge-full-design-microamp-hours = <1430000>;

>>>>>>>> +               constant-charge-microamp = <300000>;

>>>>>>>>         };

>>>>>>>>

>>>>>>>>         charger: charger@11 {

>>>>>>>> --

>>>>>>>> 2.9.3

>>>>>>>>

>>>>>>

>>>>>> --

>>>>>> Quentin Schulz, Free Electrons

>>>>>> Embedded Linux and Kernel engineering

>>>>>> http://free-electrons.com

>>>>

>>>> --

>>>> Quentin Schulz, Free Electrons

>>>> Embedded Linux and Kernel engineering

>>>> http://free-electrons.com

>

> --

> Quentin Schulz, Free Electrons

> Embedded Linux and Kernel engineering

> http://free-electrons.com
Quentin Schulz March 29, 2017, 7:54 a.m. | #6
Hi,

On 29/03/2017 09:39, Liam Breck wrote:
> On Wed, Mar 29, 2017 at 12:09 AM, Quentin Schulz

> <quentin.schulz@free-electrons.com> wrote:

>> Hi Liam,

>>

>> On 29/03/2017 08:55, Liam Breck wrote:

>>> Hi Quentin,

>>>

>>> On Thu, Mar 16, 2017 at 12:42 AM, Liam Breck <liam@networkimprov.net> wrote:

>>>> On Thu, Mar 16, 2017 at 12:03 AM, Quentin Schulz

>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>> Hi Liam,

>>>>>

>>>>> On 16/03/2017 07:27, Liam Breck wrote:

>>>>>> Hi Rob,

>>>>>>

>>>>>> On Wed, Mar 15, 2017 at 6:10 AM, Quentin Schulz

>>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>>> Hi Liam,

>>>>>>>

>>>>>>> On 15/03/2017 13:08, Liam Breck wrote:

>>>>>>>> I dropped most of the CCs, pls re-add anyone essential. Use Cc lines

>>>>>>>> in patch description to direct a patch to interested parties and

>>>>>>>> relevant lists. I don't want to see all 19 patches in this series.

>>>>>>>>

>>>>>>>> On Wed, Mar 15, 2017 at 3:55 AM, Quentin Schulz

>>>>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>>>>> This adds the constant-charge-current property to the list of optional

>>>>>>>>> properties of the battery.

>>>>>>>>>

>>>>>>>>> The constant charge current is critical for batteries as they can't

>>>>>>>>> handle all charge currents.

>>>>>>>>>

>>>>>>>>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

>>>>>>>>> Acked-by: Rob Herring <robh@kernel.org>

>>>>>>>>> ---

>>>>>>>>>

>>>>>>>>> v4:

>>>>>>>>>  - switch from constant-charge-current-microamp to constant-charge-microamp,

>>>>>>

>>>>>> Sebastian is on record supporting name alignment between DT:battery

>>>>>> properties and enum power_supply_property.

>>>>>>

>>>>>> Could you OK a change back to constant-charge-current-microamp in this patch?

>>>>>>

>>>>>> Note that the following could appear in DT:battery in future:

>>>>>>

>>>>>> constant-charge-current-microamp

>>>>>> constant-charge-current-max-microamp

>>>>>

>>>>> OK. I am actually setting max constant charge current and constant

>>>>> current charge with the same DT property so I might need to adapt my

>>>>> patches.

>>>>

>>>> I suspect you should set battery:*-current-max with DT, as -current is

>>>> "programmed by charger" so seems to be a stat, not a fixed

>>>> characteristic.

>>>

>>> Did you resolve this issue?

>>>

>>

>> Sorry, completely missed your first mail.

>>

>> Constant charge current is actually what I set in the PMIC. The maximum

>> constant charge current is completely PMIC-agnostic in my driver as it

>> is used to tell the user that (s)he shouldn't really have a constant

>> charge current over the maximum limit as the battery might not be able

>> to handle such high current.

>>

>> What I suggest is to have both properties in DT. I'll set the maximum as

>> I do today and we can give the user the ability to set a "default"

>> constant charge current (below maximum constant charge current) in the

>> DT. Maybe we do not want to recharge your battery with the maximum value

>> by default?

> 

> The scope here is just static battery characteristics. For the battery

> node, I think constant-charge-current-max-microamp is the relevant

> term.


If it's only for static battery characteristics, I agree.


> If we added both properties, one would be an alias for the

> other, which doesn't seem useful.

> 


Hum. Not really an alias. In my driver, I have a maximum which avoids to
set a constant charge current higher than what the battery is supposed
to be able to handle. The maximum can be increased via sysfs if ever the
user decides to go wild (or if (s)he changes the battery for example).
The maximum is never input in any of PMIC registers, it is not dealing
with the PMIC at all.

If I have only the max constant charge current in the DT, I'll set the
max and constant charge current with the same DT entry. That's perfectly
fine.

However, what I was thinking is to have a "default" value taken from DT
for constant charge current (which will be below maximum ccc) if ever
someone wants to set a maximum but use a lower ccc value. Anyway, I
guess it's more a "fancy" feature than a requirement (unlike max-ccc).

> The pmic can report both independently of the battery characteristic,

> and take a driver-specific DT property for

> constant-charge-current-microamp which it applies if less than the

> battery's -max setting.


Indeed.

> Or you could set that in userspace via

> /sys/class.../constant_charge_current.


The goal is to have both. The DT for default values (given by the
vendor/upstream) and sysfs for custom values (interesting if you don't
want to/can't recompile a DT.

> The charger's -max value would

> be a characteristic of its regulator.

> 


I don't really understand what you mean by that.

> Or am I missing something...?

> 

>>> Rob & Sebastian want me to merge all items for

>>> bindings/power/supply/battery.txt. If I do that I'll also roll up

>>> their counterparts in power_supply_core.c and submit a patchset for

>>> those two files.

>>>

>>

>> I guess that adding the two properties make sense, don't you think?

>>

>> Also, could you Cc me on your next version of your patches? So I know

>> when to rebase and slightly rework my patches once your patch series is

>> merged.

> 

> Surely.

> 

>> Thanks,

>> Quentin

>>

>>>> You may program your charger's -current with the battery's

>>>> -current-max, of course.

>>>>

>>>> Note that your charger also has a -current-max characteristic, likely

>>>> different than your battery. You may not need that in DT tho.

>>>>

>>>>>> constant-charge-voltage-microvolt

>>>>>> constant-charge-voltage-max-microvolt

>>>>>>

>>>>>> Thanks!

>>>>>>

>>>>>>>> Must be constant-charge-current-microamp for the reasons discussed in

>>>>>>>> battery.txt - consistency with sysfs names.

>>>>>>>>

>>>>>>>

>>>>>>> Hum. Just nitpicking, but I disagree with the use of 'must'. IIRC there

>>>>>>> is nothing in the code that would require the property to be named after

>>>>>>> a property from the enum power_supply_property.

>>>>>>>

>>>>>>> I would say that you _want_ it to be named like that because it

>>>>>>> underlines the relation between the DT property and the actual impacted

>>>>>>> property in the power supply subsystem. I'm fine with this reason but in

>>>>>>> the end, the maintainer's opinion prevails (if (s)he does not want it,

>>>>>>> (s)he will not take it). So, basically, I actually don't mind either

>>>>>>> option and I see arguments on each side.

>>>>>>>

>>>>>>> So, just waiting for maintainer's opinion to make the final version of

>>>>>>> this patch.

>>>>>>>

>>>>>>> Thanks,

>>>>>>> Quentin

>>>>>>>

>>>>>>>> Also applies to power_supply_core.c patch.

>>>>>>>>

>>>>>>>> Rob: enum power_supply_property also lists constant-charge-voltage,

>>>>>>>> hence the -current

>>>>>>>>

>>>>>>>>

>>>>>>>>> added in v3

>>>>>>>>>

>>>>>>>>>  Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++

>>>>>>>>>  1 file changed, 2 insertions(+)

>>>>>>>>>

>>>>>>>>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>>> index 0278617..9594e1e 100644

>>>>>>>>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>>> @@ -7,6 +7,7 @@ Optional Properties:

>>>>>>>>>   - voltage-min-design-microvolt: drained battery voltage

>>>>>>>>>   - energy-full-design-microwatt-hours: battery design energy

>>>>>>>>>   - charge-full-design-microamp-hours: battery design capacity

>>>>>>>>> + - constant-charge-microamp: battery constant charge current

>>>>>>>>>

>>>>>>>>>  Because drivers surface properties in sysfs using names derived

>>>>>>>>>  from enum power_supply_property, e.g.

>>>>>>>>> @@ -30,6 +31,7 @@ Example:

>>>>>>>>>                 voltage-min-design-microvolt = <3200000>;

>>>>>>>>>                 energy-full-design-microwatt-hours = <5290000>;

>>>>>>>>>                 charge-full-design-microamp-hours = <1430000>;

>>>>>>>>> +               constant-charge-microamp = <300000>;

>>>>>>>>>         };

>>>>>>>>>

>>>>>>>>>         charger: charger@11 {

>>>>>>>>> --

>>>>>>>>> 2.9.3

>>>>>>>>>

>>>>>>>

>>>>>>> --

>>>>>>> Quentin Schulz, Free Electrons

>>>>>>> Embedded Linux and Kernel engineering

>>>>>>> http://free-electrons.com

>>>>>

>>>>> --

>>>>> Quentin Schulz, Free Electrons

>>>>> Embedded Linux and Kernel engineering

>>>>> http://free-electrons.com

>>

>> --

>> Quentin Schulz, Free Electrons

>> Embedded Linux and Kernel engineering

>> http://free-electrons.com


-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
Liam Breck March 30, 2017, 7:30 a.m. | #7
On Wed, Mar 29, 2017 at 11:41 PM, Quentin Schulz
<quentin.schulz@free-electrons.com> wrote:
> Hi,

>

> On 29/03/2017 11:26, Liam Breck wrote:

>> On Wed, Mar 29, 2017 at 12:54 AM, Quentin Schulz

>> <quentin.schulz@free-electrons.com> wrote:

>>> Hi,

>>>

>>> On 29/03/2017 09:39, Liam Breck wrote:

>>>> On Wed, Mar 29, 2017 at 12:09 AM, Quentin Schulz

>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>> Hi Liam,

>>>>>

>>>>> On 29/03/2017 08:55, Liam Breck wrote:

>>>>>> Hi Quentin,

>>>>>>

>>>>>> On Thu, Mar 16, 2017 at 12:42 AM, Liam Breck <liam@networkimprov.net> wrote:

>>>>>>> On Thu, Mar 16, 2017 at 12:03 AM, Quentin Schulz

>>>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>>>> Hi Liam,

>>>>>>>>

>>>>>>>> On 16/03/2017 07:27, Liam Breck wrote:

>>>>>>>>> Hi Rob,

>>>>>>>>>

>>>>>>>>> On Wed, Mar 15, 2017 at 6:10 AM, Quentin Schulz

>>>>>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>>>>>> Hi Liam,

>>>>>>>>>>

>>>>>>>>>> On 15/03/2017 13:08, Liam Breck wrote:

>>>>>>>>>>> I dropped most of the CCs, pls re-add anyone essential. Use Cc lines

>>>>>>>>>>> in patch description to direct a patch to interested parties and

>>>>>>>>>>> relevant lists. I don't want to see all 19 patches in this series.

>>>>>>>>>>>

>>>>>>>>>>> On Wed, Mar 15, 2017 at 3:55 AM, Quentin Schulz

>>>>>>>>>>> <quentin.schulz@free-electrons.com> wrote:

>>>>>>>>>>>> This adds the constant-charge-current property to the list of optional

>>>>>>>>>>>> properties of the battery.

>>>>>>>>>>>>

>>>>>>>>>>>> The constant charge current is critical for batteries as they can't

>>>>>>>>>>>> handle all charge currents.

>>>>>>>>>>>>

>>>>>>>>>>>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

>>>>>>>>>>>> Acked-by: Rob Herring <robh@kernel.org>

>>>>>>>>>>>> ---

>>>>>>>>>>>>

>>>>>>>>>>>> v4:

>>>>>>>>>>>>  - switch from constant-charge-current-microamp to constant-charge-microamp,

>>>>>>>>>

>>>>>>>>> Sebastian is on record supporting name alignment between DT:battery

>>>>>>>>> properties and enum power_supply_property.

>>>>>>>>>

>>>>>>>>> Could you OK a change back to constant-charge-current-microamp in this patch?

>>>>>>>>>

>>>>>>>>> Note that the following could appear in DT:battery in future:

>>>>>>>>>

>>>>>>>>> constant-charge-current-microamp

>>>>>>>>> constant-charge-current-max-microamp

>>>>>>>>

>>>>>>>> OK. I am actually setting max constant charge current and constant

>>>>>>>> current charge with the same DT property so I might need to adapt my

>>>>>>>> patches.

>>>>>>>

>>>>>>> I suspect you should set battery:*-current-max with DT, as -current is

>>>>>>> "programmed by charger" so seems to be a stat, not a fixed

>>>>>>> characteristic.

>>>>>>

>>>>>> Did you resolve this issue?

>>>>>>

>>>>>

>>>>> Sorry, completely missed your first mail.

>>>>>

>>>>> Constant charge current is actually what I set in the PMIC. The maximum

>>>>> constant charge current is completely PMIC-agnostic in my driver as it

>>>>> is used to tell the user that (s)he shouldn't really have a constant

>>>>> charge current over the maximum limit as the battery might not be able

>>>>> to handle such high current.

>>>>>

>>>>> What I suggest is to have both properties in DT. I'll set the maximum as

>>>>> I do today and we can give the user the ability to set a "default"

>>>>> constant charge current (below maximum constant charge current) in the

>>>>> DT. Maybe we do not want to recharge your battery with the maximum value

>>>>> by default?

>>>>

>>>> The scope here is just static battery characteristics. For the battery

>>>> node, I think constant-charge-current-max-microamp is the relevant

>>>> term.

>>>

>>> If it's only for static battery characteristics, I agree.

>>>

>>>

>>>> If we added both properties, one would be an alias for the

>>>> other, which doesn't seem useful.

>>

>> Meaning if both properties describe static characteristics of the

>> battery, they wouldn't have different meaning.

>>

>>> Hum. Not really an alias. In my driver, I have a maximum which avoids to

>>> set a constant charge current higher than what the battery is supposed

>>> to be able to handle. The maximum can be increased via sysfs if ever the

>>> user decides to go wild (or if (s)he changes the battery for example).

>>> The maximum is never input in any of PMIC registers, it is not dealing

>>> with the PMIC at all.

>>

>> Using the battery's -max as the default for your user-adjustable max

>> sounds sensible. However the user-adjustable max should perhaps appear

>> in a custom sysfs attribute, not

>> /sys/class.../constant_charge_current_max (see comment re regulator).

>>

>

> Why?


Because charger's ccc_max should refer to its electrical
characteristics, not a user-adjustable setting. Maybe
/sys/class.../constant_charge_current_max_local or similar.

>> If the battery changes, the DT battery node should also change, esp if

>> its -max drops. I realize that's not nec trivial.

>>

>

> Disagree. That's definitely not user friendly.


There are ways to field-upgrade the dtb, tho that might not be
workable in all cases :-)

>>> If I have only the max constant charge current in the DT, I'll set the

>>> max and constant charge current with the same DT entry. That's perfectly

>>> fine.

>>

>> I assume the pmic ccc setting is adjustable via

>> /sys/class.../constant_charge_current?

>>

>

> Yes, it is then limited by a user-modifiable constant_charge_current_max.

>

>>> However, what I was thinking is to have a "default" value taken from DT

>>> for constant charge current (which will be below maximum ccc) if ever

>>> someone wants to set a maximum but use a lower ccc value. Anyway, I

>>> guess it's more a "fancy" feature than a requirement (unlike max-ccc).

>>

>> Maybe a lower default ccc than battery's -max could be provided via a

>> % value in the pmic DT node? Then multiply battery -max by that to set

>> ccc.

>>

>

> That's battery-specific, why would you want to put it in the PMIC node?


A % modifier is not too battery-specific. If you want a specific
alternate default ccc, you could certainly put it in the battery node,
and read it from your driver the way power_supply_get_battery_info()
does. But if you are expecting battery changes which alter
characteristics, the less you hard-wire into DT, the better.

>>>> The pmic can report both independently of the battery characteristic,

>>>> and take a driver-specific DT property for

>>>> constant-charge-current-microamp which it applies if less than the

>>>> battery's -max setting.

>>>

>>> Indeed.

>>>

>>>> Or you could set that in userspace via

>>>> /sys/class.../constant_charge_current.

>>>

>>> The goal is to have both. The DT for default values (given by the

>>> vendor/upstream) and sysfs for custom values (interesting if you don't

>>> want to/can't recompile a DT.

>>>

>>>> The charger's -max value would

>>>> be a characteristic of its regulator.

>>>>

>>>

>>> I don't really understand what you mean by that.

>>

>> I believe the pmic's -max value is a characteristic of its electrical

>> design, the max current it can deliver. The power_supply_class docs

>> are not very clear - "maximum charge current supported by the power

>> supply object".

>>

>

> This PMIC can deliver a maximum of 1.8A or 2.5A depending on the variant

> for constant charge current but you do not want to easily allow your

> user to put such a high value as the battery is most likely not able to

> handle such a high current.


Right, and /sys/class.../constant_charge_current_max should probably
report exactly that. Hence the suggestion for ccc_max_local for the
adjustable ccc_max.

We really shouldn't be wondering what do do here, but alas, the kernel
power-supply framework is a bit under-developed :-p

Anyway I plan to add constant-charge-current-max-microamp in the
forthcoming patchset.

>>>> Or am I missing something...?

>>>>

>>>>>> Rob & Sebastian want me to merge all items for

>>>>>> bindings/power/supply/battery.txt. If I do that I'll also roll up

>>>>>> their counterparts in power_supply_core.c and submit a patchset for

>>>>>> those two files.

>>>>>>

>>>>>

>>>>> I guess that adding the two properties make sense, don't you think?

>>>>>

>>>>> Also, could you Cc me on your next version of your patches? So I know

>>>>> when to rebase and slightly rework my patches once your patch series is

>>>>> merged.

>>>>

>>>> Surely.

>>>>

>>>>> Thanks,

>>>>> Quentin

>>>>>

>>>>>>> You may program your charger's -current with the battery's

>>>>>>> -current-max, of course.

>>>>>>>

>>>>>>> Note that your charger also has a -current-max characteristic, likely

>>>>>>> different than your battery. You may not need that in DT tho.

>>>>>>>

>>>>>>>>> constant-charge-voltage-microvolt

>>>>>>>>> constant-charge-voltage-max-microvolt

>>>>>>>>>

>>>>>>>>> Thanks!

>>>>>>>>>

>>>>>>>>>>> Must be constant-charge-current-microamp for the reasons discussed in

>>>>>>>>>>> battery.txt - consistency with sysfs names.

>>>>>>>>>>>

>>>>>>>>>>

>>>>>>>>>> Hum. Just nitpicking, but I disagree with the use of 'must'. IIRC there

>>>>>>>>>> is nothing in the code that would require the property to be named after

>>>>>>>>>> a property from the enum power_supply_property.

>>>>>>>>>>

>>>>>>>>>> I would say that you _want_ it to be named like that because it

>>>>>>>>>> underlines the relation between the DT property and the actual impacted

>>>>>>>>>> property in the power supply subsystem. I'm fine with this reason but in

>>>>>>>>>> the end, the maintainer's opinion prevails (if (s)he does not want it,

>>>>>>>>>> (s)he will not take it). So, basically, I actually don't mind either

>>>>>>>>>> option and I see arguments on each side.

>>>>>>>>>>

>>>>>>>>>> So, just waiting for maintainer's opinion to make the final version of

>>>>>>>>>> this patch.

>>>>>>>>>>

>>>>>>>>>> Thanks,

>>>>>>>>>> Quentin

>>>>>>>>>>

>>>>>>>>>>> Also applies to power_supply_core.c patch.

>>>>>>>>>>>

>>>>>>>>>>> Rob: enum power_supply_property also lists constant-charge-voltage,

>>>>>>>>>>> hence the -current

>>>>>>>>>>>

>>>>>>>>>>>

>>>>>>>>>>>> added in v3

>>>>>>>>>>>>

>>>>>>>>>>>>  Documentation/devicetree/bindings/power/supply/battery.txt | 2 ++

>>>>>>>>>>>>  1 file changed, 2 insertions(+)

>>>>>>>>>>>>

>>>>>>>>>>>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>>>>>> index 0278617..9594e1e 100644

>>>>>>>>>>>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>>>>>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt

>>>>>>>>>>>> @@ -7,6 +7,7 @@ Optional Properties:

>>>>>>>>>>>>   - voltage-min-design-microvolt: drained battery voltage

>>>>>>>>>>>>   - energy-full-design-microwatt-hours: battery design energy

>>>>>>>>>>>>   - charge-full-design-microamp-hours: battery design capacity

>>>>>>>>>>>> + - constant-charge-microamp: battery constant charge current

>>>>>>>>>>>>

>>>>>>>>>>>>  Because drivers surface properties in sysfs using names derived

>>>>>>>>>>>>  from enum power_supply_property, e.g.

>>>>>>>>>>>> @@ -30,6 +31,7 @@ Example:

>>>>>>>>>>>>                 voltage-min-design-microvolt = <3200000>;

>>>>>>>>>>>>                 energy-full-design-microwatt-hours = <5290000>;

>>>>>>>>>>>>                 charge-full-design-microamp-hours = <1430000>;

>>>>>>>>>>>> +               constant-charge-microamp = <300000>;

>>>>>>>>>>>>         };

>>>>>>>>>>>>

>>>>>>>>>>>>         charger: charger@11 {

>>>>>>>>>>>> --

>>>>>>>>>>>> 2.9.3

>>>>>>>>>>>>

>>>>>>>>>>

>>>>>>>>>> --

>>>>>>>>>> Quentin Schulz, Free Electrons

>>>>>>>>>> Embedded Linux and Kernel engineering

>>>>>>>>>> http://free-electrons.com

>>>>>>>>

>>>>>>>> --

>>>>>>>> Quentin Schulz, Free Electrons

>>>>>>>> Embedded Linux and Kernel engineering

>>>>>>>> http://free-electrons.com

>>>>>

>>>>> --

>>>>> Quentin Schulz, Free Electrons

>>>>> Embedded Linux and Kernel engineering

>>>>> http://free-electrons.com

>>>

>>> --

>>> Quentin Schulz, Free Electrons

>>> Embedded Linux and Kernel engineering

>>> http://free-electrons.com

>

> --

> Quentin Schulz, Free Electrons

> Embedded Linux and Kernel engineering

> http://free-electrons.com

Patch

diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt
index 0278617..9594e1e 100644
--- a/Documentation/devicetree/bindings/power/supply/battery.txt
+++ b/Documentation/devicetree/bindings/power/supply/battery.txt
@@ -7,6 +7,7 @@  Optional Properties:
  - voltage-min-design-microvolt: drained battery voltage
  - energy-full-design-microwatt-hours: battery design energy
  - charge-full-design-microamp-hours: battery design capacity
+ - constant-charge-microamp: battery constant charge current
 
 Because drivers surface properties in sysfs using names derived
 from enum power_supply_property, e.g.
@@ -30,6 +31,7 @@  Example:
 		voltage-min-design-microvolt = <3200000>;
 		energy-full-design-microwatt-hours = <5290000>;
 		charge-full-design-microamp-hours = <1430000>;
+		constant-charge-microamp = <300000>;
 	};
 
 	charger: charger@11 {