[PATCH 5.10 118/132] iio: adc: axp20x_adc: fix charging current reporting on AXP22x

Greg Kroah-Hartman
2021-12-13T10:40:03Z

From: Evgeny Boger <boger@wirenboard.com>

commit 92beafb76a31bdc02649eb44e93a8e4f4cfcdbe8 upstream.

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.

Fixes: 0e34d5de961d ("iio: adc: add support for X-Powers AXP20X and AXP22X PMICs ADCs")
Signed-off-by: Evgeny Boger <boger@wirenboard.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20211116213746.264378-1-boger@wirenboard.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/adc/axp20x_adc.c | 18 +++---------------
1 file changed, 3 insertions(+), 15 deletions(-)

--- a/drivers/iio/adc/axp20x_adc.c
+++ b/drivers/iio/adc/axp20x_adc.c
@@ -251,19 +251,8 @@ static int axp22x_adc_raw(struct iio_dev
struct iio_chan_spec const *chan, int *val)
{
struct axp20x_adc_iio *info = iio_priv(indio_dev);
- int size;

- /*
- * N.B.: Unlike the Chinese datasheets tell, the charging current is
- * stored on 12 bits, not 13 bits. Only discharging current is on 13
- * bits.
- */
- if (chan->type == IIO_CURRENT && chan->channel == AXP22X_BATT_DISCHRG_I)
- size = 13;
- else
- size = 12;
-
- *val = axp20x_read_variable_width(info->regmap, chan->address, size);
+ *val = axp20x_read_variable_width(info->regmap, chan->address, 12);
if (*val < 0)
return *val;

@@ -386,9 +375,8 @@ static int axp22x_adc_scale(struct iio_c
return IIO_VAL_INT_PLUS_MICRO;

case IIO_CURRENT:
- *val = 0;
- *val2 = 500000;
- return IIO_VAL_INT_PLUS_MICRO;
+ *val = 1;
+ return IIO_VAL_INT;

case IIO_TEMP:
*val = 100;