iio: accel: bmi088: Modified the scale calculate

The units after application of scale are 100*m/s^2,
The scale calculation is only for the device
with the range of 3, 6, 12, and 24g,
but some other chips have a range of 2, 4, 6, and 8g.

Modified the scales from formula to a list, the scales in the list are
calculated as 9.8/32768*pow(2,reg41+1)*1.5, refer to datasheet 5.3.4.
The new units after the application of scale are m/s^2.

Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Signed-off-by: LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn>
Link: https://lore.kernel.org/r/20220526133359.2261928-2-Qing-wu.Li@leica-geosystems.com.cn
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/accel/bmi088-accel-core.c b/drivers/iio/accel/bmi088-accel-core.c
index 8b2728b..1cb6312 100644 (file)
--- a/drivers/iio/accel/bmi088-accel-core.c
+++ b/drivers/iio/accel/bmi088-accel-core.c
@@ -6,6 +6,7 @@
  * Copyright (c) 2018-2021, Topic Embedded Products
  */
 
+#include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -73,6 +74,8 @@
 #define BMI088_ACCEL_FIFO_MODE_FIFO                    0x40
 #define BMI088_ACCEL_FIFO_MODE_STREAM                  0x80
 
+#define BMIO088_ACCEL_ACC_RANGE_MSK                    GENMASK(1, 0)
+
 enum bmi088_accel_axis {
        AXIS_X,
        AXIS_Y,
@@ -119,6 +122,7 @@ struct bmi088_accel_chip_info {
        u8 chip_id;
        const struct iio_chan_spec *channels;
        int num_channels;
+       const int scale_table[4][2];
 };
 
 struct bmi088_accel_data {
@@ -280,6 +284,7 @@ static int bmi088_accel_read_raw(struct iio_dev *indio_dev,
        struct bmi088_accel_data *data = iio_priv(indio_dev);
        struct device *dev = regmap_get_device(data->regmap);
        int ret;
+       int reg;
 
        switch (mask) {
        case IIO_CHAN_INFO_RAW:
@@ -330,13 +335,14 @@ static int bmi088_accel_read_raw(struct iio_dev *indio_dev,
                                return ret;
 
                        ret = regmap_read(data->regmap,
-                                         BMI088_ACCEL_REG_ACC_RANGE, val);
+                                         BMI088_ACCEL_REG_ACC_RANGE, &reg);
                        if (ret)
                                goto out_read_raw_pm_put;
 
-                       *val2 = 15 - (*val & 0x3);
-                       *val = 3 * 980;
-                       ret = IIO_VAL_FRACTIONAL_LOG2;
+                       reg = FIELD_GET(BMIO088_ACCEL_ACC_RANGE_MSK, reg);
+                       *val  = data->chip_info->scale_table[reg][0];
+                       *val2 = data->chip_info->scale_table[reg][1];
+                       ret = IIO_VAL_INT_PLUS_MICRO;
 
                        goto out_read_raw_pm_put;
                default:
@@ -432,6 +438,7 @@ static const struct bmi088_accel_chip_info bmi088_accel_chip_info_tbl[] = {
                .chip_id = 0x1E,
                .channels = bmi088_accel_channels,
                .num_channels = ARRAY_SIZE(bmi088_accel_channels),
+               .scale_table = {{0, 897}, {0, 1794}, {0, 3589}, {0, 7178}},
        },
 };