Re: [PATCH v7 7/7] iio: imu: inv_icm42607: Add accelerometer calibbias support

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 26 Oct 2026 12:02:55 +0100
Kanak Shilledar <kanak.shilledar@axis.com> wrote:

> Expose IIO_CHAN_INFO_CALIBBIAS on the accelerometer channels. The
> registers are stored in MREG1. The calibration bias is written to
> OFFSET_USER4 to OFFSET_USER8 registers in MREG1. Reject the out of
> limit calibbias values instead of clamping it.
> 
> Datasheet: https://www.invensense.tdk.com/en-us/products/3-axis/icm-42370-p
> Datasheet: https://www.lcsc.com/product-detail/C5129967.html
> Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
> Signed-off-by: Kanak Shilledar <kanak.shilledar@axis.com>
Minor thing inline given you are going to be doing a v8

Thanks,

Jonathan

> diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607_accel.c b/drivers/iio/imu/inv_icm42607/inv_icm42607_accel.c
> index 9a3ace3e7fcf9..2878e35d655d0 100644
> --- a/drivers/iio/imu/inv_icm42607/inv_icm42607_accel.c
> +++ b/drivers/iio/imu/inv_icm42607/inv_icm42607_accel.c
> @@ -4,6 +4,7 @@
>   */
>  
>  #include <linux/array_size.h>
> +#include <linux/bitfield.h>
>  #include <linux/bits.h>
>  #include <linux/cleanup.h>
>  #include <linux/device/devres.h>
> @@ -13,6 +14,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/regmap.h>
>  #include <linux/types.h>
> +#include <linux/units.h>
>  
>  #include "inv_icm42607.h"
>  #include "inv_icm42607_temp.h"
> @@ -22,9 +24,11 @@
>  	.type = IIO_ACCEL,							\
>  	.modified = 1,								\
>  	.channel2 = _modifier,							\
> -	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),				\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |				\
> +		BIT(IIO_CHAN_INFO_CALIBBIAS),					\
+			      BIT(IIO_CHAN_INFO_CALIBBIAS),			\
Is my preference for aligning the blocks of a load of bits.

>  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),			\
> -	.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE),		\
> +	.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE) |	\
> +		BIT(IIO_CHAN_INFO_CALIBBIAS),					\
>  	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
>  	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
>  	.scan_index = _index,							\
> @@ -56,6 +60,16 @@ static const struct iio_chan_spec inv_icm42607_accel_channels[] = {
>  	INV_ICM42607_TEMP_CHAN(INV_ICM42607_ACCEL_SCAN_TEMP),
>  };

> +
> +static int inv_icm42607_accel_write_offset(struct iio_dev *indio_dev,
> +					   struct iio_chan_spec const *chan,
> +					   int val, int val2)
> +{
> +	struct inv_icm42607_state *st = iio_device_get_drvdata(indio_dev);
> +	struct device *dev = regmap_get_device(st->map);
> +	s32 min, max;
> +	u8 msb, lsb;
> +	s16 offset;
> +	s64 val64;
> +	int ret;
> +
> +	if (chan->type != IIO_ACCEL)
> +		return -EINVAL;
> +
> +	/* inv_icm42607_accel_calibbias: min - step - max in micro */
> +	min = inv_icm42607_accel_calibbias[0] * (long)MEGA -
> +	      inv_icm42607_accel_calibbias[1];
> +	max = inv_icm42607_accel_calibbias[4] * (long)MEGA +
> +	      inv_icm42607_accel_calibbias[5];
> +
> +	val64 = val * (s64)MEGA;
> +	if (val >= 0)
> +		val64 += val2;
> +	else
> +		val64 -= val2;
> +
> +	if (val64 < min || val64 > max)
> +		return -EINVAL;
> +
> +	/*
> +	 * Convert m/s² to g then to raw value
> +	 * m/s² to g: 1 / 9.806650
> +	 * g to raw 12 bits signed, step 0.5mg: 10000 / 5
> +	 * val in micro (1000000)
> +	 * val * 10000 / (9.806650 * 1000000 * 5)
> +	 */
> +	val64 *= 10000LL;
> +	offset = DIV_S64_ROUND_CLOSEST(val64, 9806650 * 5);
> +
> +	/* Value is limited to 12 bits signed, return -EINVAL if out of range */
> +	if (offset < -2048 || offset > 2047)
> +		return -EINVAL;
> +
> +	msb = FIELD_GET(INV_ICM42607_OFFSET_MSB, offset);
> +	lsb = FIELD_GET(INV_ICM42607_OFFSET_LSB, offset);
> +
> +	PM_RUNTIME_ACQUIRE_AUTOSUSPEND(dev, pm);
> +	ret = PM_RUNTIME_ACQUIRE_ERR(&pm);
> +	if (ret)
> +		return ret;
> +
> +	guard(mutex)(&st->lock);
> +
> +	switch (chan->channel2) {
> +	case IIO_MOD_X:
> +		/* OFFSET_USER4 upper nibble is shared. */
> +		ret = regmap_update_bits(st->map, INV_ICM42607_REG_OFFSET_USER4,
> +				INV_ICM42607_OFFSET_USER_NIBBLE_HI,
Align after (
Don't worry about slightly long lines.

> +				FIELD_PREP(INV_ICM42607_OFFSET_USER_NIBBLE_HI, msb));
> +		if (ret)
> +			return ret;
> +
> +		return regmap_write(st->map, INV_ICM42607_REG_OFFSET_USER5, lsb);
> +	case IIO_MOD_Y:
> +		/* OFFSET_USER7 lower nibble is shared. */
> +		ret = regmap_update_bits(st->map, INV_ICM42607_REG_OFFSET_USER7,
> +				INV_ICM42607_OFFSET_USER_NIBBLE_LO,
> +				FIELD_PREP(INV_ICM42607_OFFSET_USER_NIBBLE_LO, msb));
> +		if (ret)
> +			return ret;
> +
> +		return regmap_write(st->map, INV_ICM42607_REG_OFFSET_USER6, lsb);
> +	case IIO_MOD_Z:
> +		/* OFFSET_USER7 upper nibble is shared. */
> +		ret = regmap_update_bits(st->map, INV_ICM42607_REG_OFFSET_USER7,
> +				INV_ICM42607_OFFSET_USER_NIBBLE_HI,
> +				FIELD_PREP(INV_ICM42607_OFFSET_USER_NIBBLE_HI, msb));
> +		if (ret)
> +			return ret;
> +
> +		return regmap_write(st->map, INV_ICM42607_REG_OFFSET_USER8, lsb);
> +	default:
> +		return -EINVAL;
> +	}
> +}