Messages in this thread | | | Date | Wed, 20 Apr 2022 00:09:59 +0200 | From | Pali Rohár <> | Subject | Re: [PATCH 0/1] power: supply: bq27xxx: expose battery data when CI=1 |
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On Tuesday 19 April 2022 23:36:46 Sicelo A. Mhlongo wrote: > We currently discard capacity information provided by the chip when the > Capacity Inaccurate flag is set. However, in many cases, having this > stale data is better than no information at all. > > Even if the chip has been fully reset, the datasheet shows that capacity > values (NAC specifically) can be seeded by using the WRTNAC facility of > the Control and Mode registers. After seeding, CI remains set, but the > capacity values are as accurate as the NAC value provided to WRTNAC is.
NAC (Nominal Available Capacity) is exported via CHARGE_NOW property.
So what about implementing CHARGE_NOW property also writable and write operation would do this WRTNAC seeding? So userspace would be able to do 'echo new_value > charge_now' and for Nokia N900 case just directly 'cat .../rx51_battery/charge_full_design > .../bq27200/charge_now'
> On the Nokia N900, such seed value can be obtained from rx51_battery, > which reads battery data directly from the battery's BSI pin. This can > be done in userspace via i2c access to the registers. With this patch, > once seeded, capacity values are available through the driver. > > The patch was successfully tested on bq27200 on the Nokia N900. > > Signed-off-by: Sicelo A. Mhlongo <absicsz@gmail.com> > > Sicelo A. Mhlongo (1): > power: supply: bq27xxx: expose battery data when CI=1 > > drivers/power/supply/bq27xxx_battery.c | 58 +++++++++++++------------- > 1 file changed, 28 insertions(+), 30 deletions(-) > > -- > 2.35.2 >
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