iio:magnetometer:mag3110: Enable user offset calibration

add IIO_CHAN_INFO_CALIBBIAS
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/magnetometer/mag3110.c

@@ -199,6 +199,13 @@ static int mag3110_read_raw(struct iio_dev *indio_dev,
 		*val = mag3110_samp_freq[i][0];
 		*val2 = mag3110_samp_freq[i][1];
 		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		ret = i2c_smbus_read_word_swapped(data->client,
+			MAG3110_OFF_X +	2 * chan->scan_index);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(ret >> 1, 14);
+		return IIO_VAL_INT;
 	}
 	return -EINVAL;
 }
@@ -223,6 +230,11 @@ static int mag3110_write_raw(struct iio_dev *indio_dev,
 		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
 		return i2c_smbus_write_byte_data(data->client,
 			MAG3110_CTRL_REG1, data->ctrl_reg1);
+	case IIO_CHAN_INFO_CALIBBIAS:
+		if (val < -10000 || val > 10000)
+			return -EINVAL;
+		return i2c_smbus_write_word_swapped(data->client,
+			MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
 	default:
 		return -EINVAL;
 	}
@@ -260,7 +272,8 @@ static irqreturn_t mag3110_trigger_handler(int irq, void *p)
 	.type = IIO_MAGN, \
 	.modified = 1, \
 	.channel2 = IIO_MOD_##axis, \
-	.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_SAMP_FREQ) | \
 		BIT(IIO_CHAN_INFO_SCALE), \
 	.scan_index = idx, \
@@ -345,7 +358,7 @@ static int mag3110_probe(struct i2c_client *client,
 		return ret;
 
 	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
-		MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);
+		MAG3110_CTRL_AUTO_MRST_EN);
 	if (ret < 0)
 		return ret;