On 2/19/2019 10:07 AM, Mark Zhang wrote:
> On 2/19/2019 2:06 AM, Rob Herring wrote:
>> On Tue, Feb 12, 2019 at 12:44 AM Mark Zhang <markz@xxxxxxxxxx> wrote:
>>>
>>> Adding documentation for 3 new backup battery charging dts
>>> properties:
>>> - maxim,charging-current-microamp
>>> - maxim,charging-voltage-microvolt
>>> - maxim,output-resister-ohms
>>
>> What's the difference between the 77620 and 77650 as there's patches
>> on the list for the 77650 too. The properties are similar, but seems
>> to be main vs. backup battery charger. We should have common
>> properties for this.
>
> Rob, it's different. The RTC in max77620 is supplied from a backup
> battery and consumes 2.0uA (IBBATT) when no other power sources are
> available. So unlike max77620 battery charging, which provides features
Oops... s/unlike max77620/unlike max77650.
Mark
> like:
>
> static enum power_supply_property max77650_charger_properties[] = {
> POWER_SUPPLY_PROP_STATUS,
> POWER_SUPPLY_PROP_ONLINE,
> POWER_SUPPLY_PROP_CHARGE_TYPE
> };
>
> For backup battery charging in max77620, what we can do is just setting
> those 3 parameters. We don't know whether it's charging, whether the
> backup battery is online, the percentage of the charging progress, and
> etc. That's why I mentioned before that it's not appropriate to create
> it as a power supply driver.
>
> Mark
>
>>
>>> Signed-off-by: Mark Zhang <markz@xxxxxxxxxx>
>>> ---
>>> .../devicetree/bindings/mfd/max77620.txt | 20 +++++++++++++++++++
>>> 1 file changed, 20 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/mfd/max77620.txt b/Documentation/devicetree/bindings/mfd/max77620.txt
>>> index 9c16d51cc15b..88825eaf2567 100644
>>> --- a/Documentation/devicetree/bindings/mfd/max77620.txt
>>> +++ b/Documentation/devicetree/bindings/mfd/max77620.txt
>>> @@ -122,6 +122,26 @@ For DT binding details of different sub modules like GPIO, pincontrol,
>>> regulator, power, please refer respective device-tree binding document
>>> under their respective sub-system directories.
>>>
>>> +Backup Battery:
>>> +==============
>>> +This sub-node configure charging backup battery of the device. Device has
>>> +support of charging the backup battery. The subnode name is "backup-battery".
>>> +The property for backup-battery child nodes as:
>>> +Presence of this child node will enable the backup battery charging.
>>> +
>>> +Optional properties:
>>> + -maxim,charging-current-microamp: Charging current setting.
>>> + The device supports 50/100/200/400/600/800uA.
>>> + If this property is unavailable then it will
>>> + charge with 50uA.
>>> + -maxim,charging-voltage-microvolt: Charging Voltage Limit Setting.
>>> + Device supports 2500000/3000000/3300000/350000uV.
>>> + Default will be set to 2500mV. The voltage will be roundoff
>>> + to nearest lower side if other than above is configured.
>>> + -maxim,output-resister-ohms: Output resistor on Ohm.
>>> + Device supports 100/1000/3000/6000 Ohms.
>>> + Default will be set to 1000 Ohm.
>>> +
>>> Example:
>>> --------
>>> #include <dt-bindings/mfd/max77620.h>
>>> --
>>> 2.19.2
>>>
