iio: accel: adxl345: add calibration offset support

The ADXL345 provides the offset adjustment registers for each axis.
This adds the iio channel information for the calibraion offsets with
that feature.

Cc: Eva Rachel Retuya <eraretuya@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 7a25840d806ffb5aefc2f0b44dbf9a80c0c769e4..7b29ae8375e9d712ef69595223780652110902ec 100644 (file)
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -18,6 +18,10 @@
 #include "adxl345.h"
 
 #define ADXL345_REG_DEVID              0x00
+#define ADXL345_REG_OFSX               0x1e
+#define ADXL345_REG_OFSY               0x1f
+#define ADXL345_REG_OFSZ               0x20
+#define ADXL345_REG_OFS_AXIS(index)    (ADXL345_REG_OFSX + (index))
 #define ADXL345_REG_POWER_CTL          0x2D
 #define ADXL345_REG_DATA_FORMAT                0x31
 #define ADXL345_REG_DATAX0             0x32
@@ -56,7 +60,8 @@ struct adxl345_data {
        .modified = 1,                                                  \
        .channel2 = IIO_MOD_##axis,                                     \
        .address = index,                                               \
-       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |                  \
+               BIT(IIO_CHAN_INFO_CALIBBIAS),                           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),           \
 }
 
@@ -72,6 +77,7 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
 {
        struct adxl345_data *data = iio_priv(indio_dev);
        __le16 accel;
+       unsigned int regval;
        int ret;
 
        switch (mask) {
@@ -94,6 +100,38 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
                *val2 = adxl345_uscale;
 
                return IIO_VAL_INT_PLUS_MICRO;
+       case IIO_CHAN_INFO_CALIBBIAS:
+               ret = regmap_read(data->regmap,
+                                 ADXL345_REG_OFS_AXIS(chan->address), &regval);
+               if (ret < 0)
+                       return ret;
+               /*
+                * 8-bit resolution at +/- 2g, that is 4x accel data scale
+                * factor
+                */
+               *val = sign_extend32(regval, 7) * 4;
+
+               return IIO_VAL_INT;
+       }
+
+       return -EINVAL;
+}
+
+static int adxl345_write_raw(struct iio_dev *indio_dev,
+                           struct iio_chan_spec const *chan,
+                           int val, int val2, long mask)
+{
+       struct adxl345_data *data = iio_priv(indio_dev);
+
+       switch (mask) {
+       case IIO_CHAN_INFO_CALIBBIAS:
+               /*
+                * 8-bit resolution at +/- 2g, that is 4x accel data scale
+                * factor
+                */
+               return regmap_write(data->regmap,
+                                   ADXL345_REG_OFS_AXIS(chan->address),
+                                   val / 4);
        }
 
        return -EINVAL;
@@ -101,6 +139,7 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
 
 static const struct iio_info adxl345_info = {
        .read_raw       = adxl345_read_raw,
+       .write_raw      = adxl345_write_raw,
 };
 
 int adxl345_core_probe(struct device *dev, struct regmap *regmap,