Re: [PATCH v2] iio: adc: axp20x_adc: fix charging current reporting on AXP22x

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 21 Nov 2021 01:58:08 +0800
Chen-Yu Tsai <wens@csie.org> wrote:

> Hi,
> 
> On Sun, Nov 21, 2021 at 1:44 AM Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > On Wed, 17 Nov 2021 00:37:46 +0300
> > Evgeny Boger <boger@wirenboard.com> wrote:
> >  
> > > Both the charging and discharging currents on AXP22x are stored as
> > > 12-bit integers, in accordance with the datasheet.
> > > It's also confirmed by vendor BSP (axp20x_adc.c:axp22_icharge_to_mA).
> > >
> > > The scale factor of 0.5 is never mentioned in datasheet, nor in the
> > > vendor source code. I think it was here to compensate for
> > > erroneous addition bit in register width.
> > >
> > > Tested on custom A40i+AXP221s board with external ammeter as
> > > a reference.
> > >
> > > Signed-off-by: Evgeny Boger <boger@wirenboard.com>  
> >
> > I know Quentin has moved on from Bootlin, so looking for input from Chen-Yu Tsai
> > for these as I have no idea :)  
> 
> The datasheet only lists the registers for reading the value, but nothing
> is said about how to interpret the data read. And the datasheet lists 13
> bits split between two registers.
> 
> Evgeny mentioned that the original code is wrong, and the BSP code is
> likely right, and has test results that match. That's good enough for
> me. Unfortunately I don't have any way to double check it right now. So
> 
> Acked-by: Chen-Yu Tsai <wens@csie.org>

Applied to the fixes-togreg branch of iio.git with a fixes tag for the original
driver introduction (as it seems this dates back that far) and marked for stable.

Thanks,

Jonathan