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From:   Alexandru Ardelean <ardeleanalex@gmail.com>
Date:   Mon, 19 Jul 2021 15:05:28 +0300
Message-ID: <CA+U=Dsp078qs+nnzoZkYTwknw+j=6f=wwjV3y34qDaVAmNwV+A@mail.gmail.com>
Subject: Re: [PATCH 2/2] iio: accel: Add driver support for ADXL355
To:     Puranjay Mohan <puranjay12@gmail.com>
Cc:     "Hennerich, Michael" <Michael.Hennerich@analog.com>,
        Alexandru Ardelean <alexandru.ardelean@analog.com>,
        Jonathan Cameron <jic23@kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        "Bogdan, Dragos" <Dragos.Bogdan@analog.com>,
        Darius.Berghe@analog.com
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(

On Sun, Jul 18, 2021 at 9:01 PM Puranjay Mohan <puranjay12@gmail.com> wrote:
>
> ADXL355 is 3-axis MEMS Accelerometer. It offers low noise density,
> low 0g offset drift, low power with selectable measurement ranges.
> It also features programmable high-pass and low-pass filters.
>

Hey,

This looks pretty good.
A few comments inline.

> Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/adxl354_adxl355.pdf
> Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
> ---
>  MAINTAINERS                      |   7 +
>  drivers/iio/accel/Kconfig        |  29 ++
>  drivers/iio/accel/Makefile       |   3 +
>  drivers/iio/accel/adxl355.h      |  83 +++++
>  drivers/iio/accel/adxl355_core.c | 544 +++++++++++++++++++++++++++++++
>  drivers/iio/accel/adxl355_i2c.c  |  63 ++++
>  drivers/iio/accel/adxl355_spi.c  |  66 ++++
>  7 files changed, 795 insertions(+)
>  create mode 100644 drivers/iio/accel/adxl355.h
>  create mode 100644 drivers/iio/accel/adxl355_core.c
>  create mode 100644 drivers/iio/accel/adxl355_i2c.c
>  create mode 100644 drivers/iio/accel/adxl355_spi.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index bd7aff0c1..461f2a192 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -586,6 +586,13 @@ W: http://ez.analog.com/community/linux-device-drivers
>  F:     Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
>  F:     drivers/input/misc/adxl34x.c
>
> +ADXL355 THREE-AXIS DIGITAL ACCELEROMETER DRIVER
> +M:     Puranjay Mohan <puranjay12@gmail.com>
> +L:     linux-iio@vger.kernel.org
> +S:     Supported
> +F:     drivers/iio/accel/adxl34x.c
> +F:     Documentation/devicetree/bindings/iio/accel/adi,adxl355.yaml
> +
>  ADXL372 THREE-AXIS DIGITAL ACCELEROMETER DRIVER
>  M:     Michael Hennerich <michael.hennerich@analog.com>
>  S:     Supported
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index cceda3cec..9a65353a4 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -61,6 +61,35 @@ config ADXL345_SPI
>           will be called adxl345_spi and you will also get adxl345_core
>           for the core module.
>
> +config ADXL355
> +       tristate
> +
> +config ADXL355_I2C
> +       tristate "Analog Devices ADXL355 3-Axis Digital Accelerometer I2C Driver"
> +       depends on I2C
> +       select ADXL355
> +       select REGMAP_I2C
> +       help
> +         Say Y here if you want to build support for the Analog Devices
> +         ADXL355 3-axis digital accelerometer.
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called adxl355_i2c and you will also get adxl355_core
> +         for the core module.
> +
> +config ADXL355_SPI
> +       tristate "Analog Devices ADXL355 3-Axis Digital Accelerometer SPI Driver"
> +       depends on SPI
> +       select ADXL355
> +       select REGMAP_SPI
> +       help
> +         Say Y here if you want to build support for the Analog Devices
> +         ADXL355 3-axis digital accelerometer.
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called adxl355_spi and you will also get adxl355_core
> +         for the core module.
> +
>  config ADXL372
>         tristate
>         select IIO_BUFFER
> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> index 32cd1342a..0e4721d2d 100644
> --- a/drivers/iio/accel/Makefile
> +++ b/drivers/iio/accel/Makefile
> @@ -9,6 +9,9 @@ obj-$(CONFIG_ADIS16209) += adis16209.o
>  obj-$(CONFIG_ADXL345) += adxl345_core.o
>  obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
>  obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
> +obj-$(CONFIG_ADXL355) += adxl355_core.o
> +obj-$(CONFIG_ADXL355_I2C) += adxl355_i2c.o
> +obj-$(CONFIG_ADXL355_SPI) += adxl355_spi.o
>  obj-$(CONFIG_ADXL372) += adxl372.o
>  obj-$(CONFIG_ADXL372_I2C) += adxl372_i2c.o
>  obj-$(CONFIG_ADXL372_SPI) += adxl372_spi.o
> diff --git a/drivers/iio/accel/adxl355.h b/drivers/iio/accel/adxl355.h
> new file mode 100644
> index 000000000..e52c294d8
> --- /dev/null
> +++ b/drivers/iio/accel/adxl355.h
> @@ -0,0 +1,83 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * ADXL355 3-Axis Digital Accelerometer
> + *
> + * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
> + */
> +
> +#ifndef _ADXL355_H_
> +#define _ADXL355_H_
> +
> +#include <linux/regmap.h>
> +
> +/* ADXL355 Register Definitions */
> +#define ADXL355_DEVID_AD       0x00
> +#define ADXL355_DEVID_MST      0x01
> +#define ADXL355_PARTID         0x02
> +#define ADXL355_REVID          0x03
> +#define ADXL355_STATUS         0x04
> +#define ADXL355_FIFO_ENTRIES   0x05
> +#define ADXL355_TEMP2          0x06
> +#define ADXL355_XDATA3         0x08
> +#define ADXL355_YDATA3         0x0B
> +#define ADXL355_ZDATA3         0x0E
> +#define ADXL355_FIFO_DATA      0x11
> +#define ADXL355_OFFSET_X_H     0x1E
> +#define ADXL355_OFFSET_Y_H     0x20
> +#define ADXL355_OFFSET_Z_H     0x22
> +#define ADXL355_ACT_EN         0x24
> +#define ADXL355_ACT_THRESH_H   0x25
> +#define ADXL355_ACT_THRESH_L   0x26
> +#define ADXL355_ACT_COUNT      0x27
> +#define ADXL355_FILTER         0x28
> +#define ADXL355_FIFO_SAMPLES   0x29
> +#define ADXL355_INT_MAP                0x2A
> +#define ADXL355_SYNC           0x2B
> +#define ADXL355_RANGE          0x2C
> +#define ADXL355_POWER_CTL      0x2D
> +#define ADXL355_SELF_TEST      0x2E
> +#define ADXL355_RESET          0x2F
> +
> +#define ADXL355_DEVID_AD_VAL   0xAD
> +#define ADXL355_DEVID_MST_VAL  0x1D
> +#define ADXL355_PARTID_VAL     0xED
> +#define ADXL355_REVID_VAL      0x01
> +#define ADXL355_RESET_CODE     0x52
> +
> +#define ADXL355_POWER_CTL_MODE_MSK     GENMASK(1, 0)
> +
> +#define ADXL355_FILTER_ODR_MSK                 GENMASK(3, 0)
> +#define ADXL355_FILTER_ODR_MODE(x)             ((x) & 0xF)
> +#define ADXL355_FILTER_HPF_MSK                 GENMASK(6, 4)
> +#define ADXL355_FILTER_HPF_MODE(x)             (((x) & 0x7) << 4)
> +
> +/*
> + * The datasheet defines an intercept of 1885 LSB at 25 degC
> + * and a slope of -9.05 LSB/C. The following formula can be used to find the
> + * temperature:
> + * Temp = ((RAW - 1885)/(-9.05)) + 25 but this doesn't follow the format of
> + * the IIO which is Temp = (RAW + OFFSET) * SCALE. Hence using some rearranging
> + * we get the scale as -110.49723 and offset as -2111.25
> + */
> +#define TEMP_SCALE_VAL -110
> +#define TEMP_SCALE_VAL2 497238
> +#define TEMP_OFFSET_VAL -2111
> +#define TEMP_OFFSET_VAL2 250000
> +
> +/*
> + * At +/- 2g with 20-bit resolution, scale is given in datasheet as
> + * 3.9ug/LSB = 0.0000039 * 9.80665 = 0.00003824593 m/s^2
> + */
> +#define ADXL355_NSCALE 38245
> +
> +extern const struct regmap_range adxl355_read_reg_range[];
> +
> +extern const struct regmap_access_table adxl355_readable_regs_tbl;
> +
> +extern const struct regmap_range adxl355_write_reg_range[];
> +
> +extern const struct regmap_access_table adxl355_writeable_regs_tbl;
> +
> +int adxl355_core_probe(struct device *dev, struct regmap *regmap,
> +                      const char *name);

I would put most all these definitions in the core file, since they
are mostly used there.
I'd leave only what's shared between files here.
i.e. adxl355_core_probe() and adxl355_{read,write}able_regs_tbl here
Of course, that's my preference. The way it is done here is a fine as well.


> +#endif /* _ADXL355_H_ */
> diff --git a/drivers/iio/accel/adxl355_core.c b/drivers/iio/accel/adxl355_core.c
> new file mode 100644
> index 000000000..5fdd3c73e
> --- /dev/null
> +++ b/drivers/iio/accel/adxl355_core.c
> @@ -0,0 +1,544 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ADXL355 3-Axis Digital Accelerometer IIO core driver
> + *
> + * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
> + *
> + * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/adxl354_adxl355.pdf
> + */
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/limits.h>
> +#include <linux/math64.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#include "adxl355.h"
> +
> +const struct regmap_range adxl355_read_reg_range[] = {
> +       regmap_reg_range(ADXL355_DEVID_AD, ADXL355_FIFO_DATA),
> +       regmap_reg_range(ADXL355_OFFSET_X_H, ADXL355_SELF_TEST)
> +};
> +EXPORT_SYMBOL_GPL(adxl355_read_reg_range);

It does not look like this regmap definition is used outside of the
core file, so maybe just keep it private/static for this file?

> +
> +const struct regmap_access_table adxl355_readable_regs_tbl = {
> +       .yes_ranges = adxl355_read_reg_range,
> +       .n_yes_ranges = ARRAY_SIZE(adxl355_read_reg_range),
> +};
> +EXPORT_SYMBOL_GPL(adxl355_readable_regs_tbl);
> +
> +const struct regmap_range adxl355_write_reg_range[] = {
> +       regmap_reg_range(ADXL355_OFFSET_X_H, ADXL355_RESET)
> +};
> +EXPORT_SYMBOL_GPL(adxl355_write_reg_range);
> +

This doesn't look like it's used between files, so maybe keep it private?

> +const struct regmap_access_table adxl355_writeable_regs_tbl = {
> +       .yes_ranges = adxl355_write_reg_range,
> +       .n_yes_ranges = ARRAY_SIZE(adxl355_write_reg_range),
> +};
> +EXPORT_SYMBOL_GPL(adxl355_writeable_regs_tbl);
> +
> +enum adxl355_op_mode {
> +       ADXL355_MEASUREMENT,
> +       ADXL355_STANDBY,
> +       ADXL355_TEMP_OFF
> +};
> +
> +enum adxl355_odr {
> +       ADXL355_ODR_4000HZ,
> +       ADXL355_ODR_2000HZ,
> +       ADXL355_ODR_1000HZ,
> +       ADXL355_ODR_500HZ,
> +       ADXL355_ODR_250HZ,
> +       ADXL355_ODR_125HZ,
> +       ADXL355_ODR_62_5HZ,
> +       ADXL355_ODR_31_25HZ,
> +       ADXL355_ODR_15_625HZ,
> +       ADXL355_ODR_7_813HZ,
> +       ADXL355_ODR_3_906HZ
> +};
> +
> +enum adxl355_hpf_3db {
> +       ADXL355_HPF_OFF,
> +       ADXL355_HPF_24_7,
> +       ADXL355_HPF_6_2084,
> +       ADXL355_HPF_1_5545,
> +       ADXL355_HPF_0_3862,
> +       ADXL355_HPF_0_0954,
> +       ADXL355_HPF_0_0238
> +};
> +
> +static const int adxl355_odr_table[][2] = {
> +       [0] = {4000, 0},
> +       [1] = {2000, 0},
> +       [2] = {1000, 0},
> +       [3] = {500, 0},
> +       [4] = {250, 0},
> +       [5] = {125, 0},
> +       [6] = {62, 500000},
> +       [7] = {31, 250000},
> +       [8] = {15, 625000},
> +       [9] = {7, 813000},
> +       [10] = {3, 906000}
> +};
> +
> +static int adxl355_hpf_3db_table[7][2] = {0};

Maybe make this const as well?

> +
> +static const int adxl355_hpf_3db_multipliers[] = {
> +       0,
> +       247000,
> +       62084,
> +       15545,
> +       3862,
> +       954,
> +       238
> +};
> +
> +struct adxl355_data {
> +       struct regmap *regmap;
> +       struct device *dev;
> +       struct mutex lock; /* lock to protect op_mode */
> +       enum adxl355_op_mode op_mode;
> +       enum adxl355_odr odr;
> +       enum adxl355_hpf_3db hpf_3db;
> +       int x_calibbias;
> +       int y_calibbias;
> +       int z_calibbias;
> +};
> +
> +static int adxl355_set_op_mode(struct adxl355_data *data,
> +                              enum adxl355_op_mode op_mode)
> +{
> +       int ret;
> +
> +       if (data->op_mode == op_mode)
> +               return 0;
> +
> +       ret = regmap_update_bits(data->regmap, ADXL355_POWER_CTL,
> +                                ADXL355_POWER_CTL_MODE_MSK, op_mode);
> +       if (ret < 0)
> +               return ret;
> +
> +       data->op_mode = op_mode;
> +
> +       return ret;
> +}
> +
> +static void adxl355_fill_3db_frequency_table(struct adxl355_data *data)
> +{
> +       int i;
> +       u64 rem;
> +       u64 div;
> +       u32 multiplier;
> +       u64 odr = mul_u64_u32_shr(adxl355_odr_table[data->odr][0], 1000000, 0) +
> +                                       adxl355_odr_table[data->odr][1];
> +
> +       for (i = 0; i < ARRAY_SIZE(adxl355_hpf_3db_multipliers); i++) {
> +               multiplier = adxl355_hpf_3db_multipliers[i];
> +               div = div64_u64_rem(mul_u64_u32_shr(odr, multiplier, 0),
> +                                   100000000000000UL, &rem);
> +
> +               adxl355_hpf_3db_table[i][0] = div;
> +               adxl355_hpf_3db_table[i][1] = div_u64(rem, 100000000);
> +       }
> +}
> +
> +static int adxl355_setup(struct adxl355_data *data)
> +{
> +       unsigned int regval;
> +       int ret;
> +
> +       ret = regmap_read(data->regmap, ADXL355_DEVID_AD, &regval);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (regval != ADXL355_DEVID_AD_VAL) {
> +               dev_err(data->dev, "Invalid ADI ID 0x%02x\n", regval);
> +               return -ENODEV;
> +       }
> +
> +       ret = regmap_read(data->regmap, ADXL355_DEVID_MST, &regval);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (regval != ADXL355_DEVID_MST_VAL) {
> +               dev_err(data->dev, "Invalid MEMS ID 0x%02x\n", regval);
> +               return -ENODEV;
> +       }
> +
> +       ret = regmap_read(data->regmap, ADXL355_PARTID, &regval);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (regval != ADXL355_PARTID_VAL) {
> +               dev_err(data->dev, "Invalid DEV ID 0x%02x\n", regval);
> +               return -ENODEV;
> +       }
> +
> +       /*
> +        * Perform a software reset to make sure the device is in a consistent
> +        * state after start up.
> +        */
> +       ret = regmap_write(data->regmap, ADXL355_RESET, ADXL355_RESET_CODE);
> +       if (ret < 0)
> +               return ret;
> +
> +       adxl355_fill_3db_frequency_table(data);
> +
> +       return adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
> +}
> +
> +static int adxl355_get_temp_data(struct adxl355_data *data,
> +                                u8 addr, __be16 *out)
> +{
> +       return regmap_bulk_read(data->regmap, addr, out, sizeof(*out));
> +}
> +
> +static int adxl355_read_axis(struct adxl355_data *data, u8 addr)
> +{
> +       __be32 regval;
> +       int ret;
> +
> +       ret = regmap_bulk_read(data->regmap, addr, &regval, 3);
> +       if (ret < 0)
> +               return ret;
> +
> +       return be32_to_cpu(regval) >> 8;
> +}
> +
> +static int adxl355_find_match(const int (*freq_tbl)[2], const int n,
> +                             const int val, const int val2)
> +{
> +       int i;
> +
> +       for (i = 0; i < n; i++) {
> +               if (freq_tbl[i][0] == val && freq_tbl[i][1] == val2)
> +                       return i;
> +       }
> +
> +       return -EINVAL;
> +}
> +
> +static int adxl355_set_odr(struct adxl355_data *data,
> +                          enum adxl355_odr odr)
> +{
> +       int ret = 0;
> +
> +       mutex_lock(&data->lock);
> +
> +       if (data->odr == odr)
> +               goto out_unlock;
> +
> +       ret = adxl355_set_op_mode(data, ADXL355_STANDBY);
> +       if (ret < 0)
> +               goto out_unlock;
> +
> +       ret = regmap_update_bits(data->regmap, ADXL355_FILTER,
> +                                ADXL355_FILTER_ODR_MSK,
> +                                ADXL355_FILTER_ODR_MODE(odr));
> +       if (!ret) {
> +               data->odr = odr;
> +               adxl355_fill_3db_frequency_table(data);
> +       }
> +
> +out_unlock:
> +       ret = adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
> +       mutex_unlock(&data->lock);
> +       return ret;
> +}
> +
> +static int adxl355_set_hpf_3db(struct adxl355_data *data,
> +                              enum adxl355_hpf_3db hpf)
> +{
> +       int ret = 0;
> +
> +       mutex_lock(&data->lock);
> +
> +       if (data->hpf_3db == hpf)
> +               goto out_unlock;
> +
> +       ret = adxl355_set_op_mode(data, ADXL355_STANDBY);
> +       if (ret < 0)
> +               goto out_unlock;
> +
> +       ret = regmap_update_bits(data->regmap, ADXL355_FILTER,
> +                                ADXL355_FILTER_HPF_MSK,
> +                                ADXL355_FILTER_HPF_MODE(hpf));
> +       if (!ret)
> +               data->hpf_3db = hpf;
> +
> +out_unlock:
> +       ret = adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
> +       mutex_unlock(&data->lock);
> +       return ret;
> +}
> +
> +static int adxl355_set_calibbias(struct adxl355_data *data,
> +                                int scan_index, int calibbias)
> +{
> +       int ret = 0;
> +       __be16 reg = cpu_to_be16(calibbias);
> +
> +       mutex_lock(&data->lock);
> +
> +       ret = adxl355_set_op_mode(data, ADXL355_STANDBY);
> +       if (ret < 0)
> +               goto out_unlock;
> +
> +       switch (scan_index) {
> +       case 0:
> +               ret = regmap_bulk_write(data->regmap, ADXL355_OFFSET_X_H,
> +                                       &reg, 2);
> +               if (ret < 0)
> +                       goto out_unlock;
> +               data->x_calibbias = calibbias;
> +               break;
> +       case 1:
> +               ret = regmap_bulk_write(data->regmap, ADXL355_OFFSET_Y_H,
> +                                       &reg, 2);
> +               if (ret < 0)
> +                       goto out_unlock;
> +               data->y_calibbias = calibbias;
> +               break;
> +       case 2:
> +               ret = regmap_bulk_write(data->regmap, ADXL355_OFFSET_Z_H,
> +                                       &reg, 2);
> +               if (ret < 0)
> +                       goto out_unlock;
> +               data->z_calibbias = calibbias;
> +               break;
> +       default:
> +               ret = -EINVAL;
> +               break;
> +       }
> +
> +out_unlock:
> +       ret = adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
> +       mutex_unlock(&data->lock);
> +       return ret;
> +}
> +
> +static int adxl355_read_raw(struct iio_dev *indio_dev,
> +                           struct iio_chan_spec const *chan,
> +                           int *val, int *val2, long mask)
> +{
> +       struct adxl355_data *data = iio_priv(indio_dev);
> +       int ret;
> +       __be16 out;
> +
> +       switch (mask) {
> +       case IIO_CHAN_INFO_RAW:
> +               switch (chan->type) {
> +               case IIO_TEMP:
> +                       ret = adxl355_get_temp_data(data, chan->address, &out);
> +                       if (ret < 0)
> +                               break;
> +                       *val = be16_to_cpu(out);
> +                       ret = IIO_VAL_INT;
> +                       break;
> +
> +               case IIO_ACCEL:
> +                       ret = adxl355_read_axis(data, chan->address);
> +                       if (ret < 0)
> +                               break;
> +                       *val = sign_extend32(ret >> (chan->scan_type.shift),
> +                                            chan->scan_type.realbits - 1);
> +                       ret = IIO_VAL_INT;
> +                       break;
> +
> +               default:
> +                       ret = -EINVAL;
> +                       break;
> +               }
> +
> +               return ret;
> +       case IIO_CHAN_INFO_SCALE:
> +               switch (chan->type) {
> +               case IIO_TEMP:
> +                       *val = TEMP_SCALE_VAL;
> +                       *val2 = TEMP_SCALE_VAL2;
> +                       return IIO_VAL_INT_PLUS_MICRO;
> +               case IIO_ACCEL:
> +                       *val = 0;
> +                       *val2 = ADXL355_NSCALE;
> +                       return IIO_VAL_INT_PLUS_NANO;
> +               default:
> +                       return -EINVAL;
> +               }
> +       case IIO_CHAN_INFO_OFFSET:
> +               *val = TEMP_OFFSET_VAL;
> +               *val2 = TEMP_OFFSET_VAL2;
> +               return IIO_VAL_INT_PLUS_MICRO;
> +       case IIO_CHAN_INFO_CALIBBIAS:
> +               if (chan->scan_index == 0)
> +                       *val = data->x_calibbias;
> +               else if (chan->scan_index == 1)
> +                       *val = data->y_calibbias;
> +               else
> +                       *val = data->z_calibbias;
> +               *val = sign_extend32(*val, 15);
> +               return IIO_VAL_INT;
> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               *val = adxl355_odr_table[data->odr][0];
> +               *val2 = adxl355_odr_table[data->odr][1];
> +               return IIO_VAL_INT_PLUS_MICRO;
> +       case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
> +               *val = adxl355_hpf_3db_table[data->hpf_3db][0];
> +               *val2 = adxl355_hpf_3db_table[data->hpf_3db][1];
> +               return IIO_VAL_INT_PLUS_MICRO;
> +       }
> +       return -EINVAL;
> +}
> +
> +static int adxl355_write_raw(struct iio_dev *indio_dev,
> +                            struct iio_chan_spec const *chan,
> +                            int val, int val2, long mask)
> +{
> +       struct adxl355_data *data = iio_priv(indio_dev);
> +       int odr_idx, hpf_idx, calibbias, ret;
> +
> +       switch (mask) {
> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               odr_idx = adxl355_find_match(adxl355_odr_table,
> +                                            ARRAY_SIZE(adxl355_odr_table),
> +                                            val, val2);
> +               if (odr_idx < 0)
> +                       return odr_idx;
> +
> +               return adxl355_set_odr(data, odr_idx);
> +       case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
> +               hpf_idx = adxl355_find_match(adxl355_hpf_3db_table,
> +                                            ARRAY_SIZE(adxl355_hpf_3db_table),
> +                                            val, val2);
> +               if (hpf_idx < 0)
> +                       return hpf_idx;
> +
> +               return adxl355_set_hpf_3db(data, hpf_idx);
> +       case IIO_CHAN_INFO_CALIBBIAS:
> +               calibbias = clamp_t(int, val, S16_MIN, S16_MAX);
> +               ret = adxl355_set_calibbias(data, chan->scan_index, calibbias);
> +
> +               return ret;

return adxl355_set_calibbias();    directly


> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +static int adxl355_read_avail(struct iio_dev *indio_dev,
> +                             struct iio_chan_spec const *chan,
> +                             const int **vals, int *type, int *length,
> +                             long mask)
> +{
> +       switch (mask) {
> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               *vals = (const int *)adxl355_odr_table;
> +               *type = IIO_VAL_INT_PLUS_MICRO;
> +               /* Values are stored in a 2D matrix */
> +               *length = ARRAY_SIZE(adxl355_odr_table) * 2;
> +
> +               return IIO_AVAIL_LIST;
> +       case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
> +               *vals = (const int *)adxl355_hpf_3db_table;
> +               *type = IIO_VAL_INT_PLUS_MICRO;
> +               /* Values are stored in a 2D matrix */
> +               *length = ARRAY_SIZE(adxl355_hpf_3db_table) * 2;
> +
> +               return IIO_AVAIL_LIST;
> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +static const unsigned long adxl355_avail_scan_masks[] = {
> +       GENMASK(3, 0),
> +       0
> +};
> +
> +static const struct iio_info adxl355_info = {
> +       .read_raw       = adxl355_read_raw,
> +       .write_raw      = adxl355_write_raw,
> +       .read_avail     = &adxl355_read_avail
> +};
> +
> +#define ADXL355_ACCEL_CHANNEL(index, reg, axis) {                      \
> +       .type = IIO_ACCEL,                                              \
> +       .address = reg,                                                 \
> +       .modified = 1,                                                  \
> +       .channel2 = IIO_MOD_##axis,                                     \
> +       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |                  \
> +                             BIT(IIO_CHAN_INFO_CALIBBIAS),             \
> +       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |          \
> +                                   BIT(IIO_CHAN_INFO_SAMP_FREQ) |      \
> +               BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),      \
> +       .info_mask_shared_by_type_available =                           \
> +               BIT(IIO_CHAN_INFO_SAMP_FREQ) |                          \
> +               BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),      \
> +       .scan_index = index,                                            \
> +       .scan_type = {                                                  \
> +               .sign = 's',                                            \
> +               .realbits = 20,                                         \
> +               .storagebits = 32,                                      \
> +               .shift = 4,                                             \
> +               .endianness = IIO_BE,                                   \
> +       }                                                               \
> +}
> +
> +static const struct iio_chan_spec adxl355_channels[] = {
> +       ADXL355_ACCEL_CHANNEL(0, ADXL355_XDATA3, X),
> +       ADXL355_ACCEL_CHANNEL(1, ADXL355_YDATA3, Y),
> +       ADXL355_ACCEL_CHANNEL(2, ADXL355_ZDATA3, Z),
> +       {
> +               .type = IIO_TEMP,
> +               .address = ADXL355_TEMP2,
> +               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +                                     BIT(IIO_CHAN_INFO_SCALE) |
> +                                     BIT(IIO_CHAN_INFO_OFFSET),
> +               .scan_index = 3,
> +               .scan_type = {
> +                       .sign = 's',
> +                       .realbits = 12,
> +                       .storagebits = 16,
> +                       .endianness = IIO_BE,
> +               },
> +       }
> +};
> +
> +int adxl355_core_probe(struct device *dev, struct regmap *regmap,
> +                      const char *name)
> +{
> +       struct adxl355_data *data;
> +       struct iio_dev *indio_dev;
> +       int ret;
> +
> +       indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +       if (!indio_dev)
> +               return -ENOMEM;
> +
> +       data = iio_priv(indio_dev);
> +       data->regmap = regmap;
> +       data->dev = dev;
> +       data->op_mode = ADXL355_STANDBY;
> +       mutex_init(&data->lock);
> +
> +       indio_dev->dev.parent = dev;

This parent assignment can be removed.
It's done in devm_iio_device_alloc()

> +       indio_dev->name = name;
> +       indio_dev->info = &adxl355_info;
> +       indio_dev->modes = INDIO_DIRECT_MODE;
> +       indio_dev->channels = adxl355_channels;
> +       indio_dev->num_channels = ARRAY_SIZE(adxl355_channels);
> +       indio_dev->available_scan_masks = adxl355_avail_scan_masks;
> +
> +       ret = adxl355_setup(data);
> +       if (ret < 0) {
> +               dev_err(dev, "ADXL355 setup failed\n");
> +               return ret;
> +       }
> +
> +       return devm_iio_device_register(dev, indio_dev);
> +}
> +EXPORT_SYMBOL_GPL(adxl355_core_probe);
> +
> +MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
> +MODULE_DESCRIPTION("ADXL355 3-Axis Digital Accelerometer core driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iio/accel/adxl355_i2c.c b/drivers/iio/accel/adxl355_i2c.c
> new file mode 100644
> index 000000000..1c9764129
> --- /dev/null
> +++ b/drivers/iio/accel/adxl355_i2c.c
> @@ -0,0 +1,63 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ADXL355 3-Axis Digital Accelerometer I2C driver
> + *
> + * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#include "adxl355.h"
> +
> +static const struct regmap_config adxl355_i2c_regmap_config = {
> +       .reg_bits = 8,
> +       .val_bits = 8,
> +       .max_register = 0x2F,
> +       .rd_table = &adxl355_readable_regs_tbl,
> +       .wr_table = &adxl355_writeable_regs_tbl
> +};
> +
> +static int adxl355_i2c_probe(struct i2c_client *client)
> +{
> +       struct regmap *regmap;
> +
> +       regmap = devm_regmap_init_i2c(client, &adxl355_i2c_regmap_config);
> +       if (IS_ERR(regmap)) {
> +               dev_err(&client->dev, "Error initializing i2c regmap: %ld\n",
> +                       PTR_ERR(regmap));
> +               return PTR_ERR(regmap);
> +       }
> +
> +       return adxl355_core_probe(&client->dev, regmap, client->name);
> +}
> +
> +static const struct i2c_device_id adxl355_i2c_id[] = {
> +       { "adxl355", 0 },
> +       { }
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, adxl355_i2c_id);
> +
> +static const struct of_device_id adxl355_of_match[] = {
> +       { .compatible = "adi,adxl355" },
> +       { },

Comma can be removed.
It's a null-terminator.

> +};
> +
> +MODULE_DEVICE_TABLE(of, adxl355_of_match);
> +
> +static struct i2c_driver adxl355_i2c_driver = {
> +       .driver = {
> +               .name   = "adxl355_i2c",
> +               .of_match_table = adxl355_of_match,
> +       },
> +       .probe_new      = adxl355_i2c_probe,
> +       .id_table       = adxl355_i2c_id,
> +};
> +
> +module_i2c_driver(adxl355_i2c_driver);
> +
> +MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
> +MODULE_DESCRIPTION("ADXL355 3-Axis Digital Accelerometer I2C driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iio/accel/adxl355_spi.c b/drivers/iio/accel/adxl355_spi.c
> new file mode 100644
> index 000000000..ae02cbfad
> --- /dev/null
> +++ b/drivers/iio/accel/adxl355_spi.c
> @@ -0,0 +1,66 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ADXL355 3-Axis Digital Accelerometer SPI driver
> + *
> + * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/spi/spi.h>
> +
> +#include "adxl355.h"
> +
> +static const struct regmap_config adxl355_spi_regmap_config = {
> +       .reg_bits = 7,
> +       .pad_bits = 1,
> +       .val_bits = 8,
> +       .read_flag_mask = BIT(0),
> +       .max_register = 0x2F,
> +       .rd_table = &adxl355_readable_regs_tbl,
> +       .wr_table = &adxl355_writeable_regs_tbl
> +};
> +
> +static int adxl355_spi_probe(struct spi_device *spi)
> +{
> +       const struct spi_device_id *id = spi_get_device_id(spi);
> +       struct regmap *regmap;
> +
> +       regmap = devm_regmap_init_spi(spi, &adxl355_spi_regmap_config);
> +       if (IS_ERR(regmap)) {
> +               dev_err(&spi->dev, "Error initializing spi regmap: %ld\n",
> +                       PTR_ERR(regmap));
> +               return PTR_ERR(regmap);
> +       }
> +
> +       return adxl355_core_probe(&spi->dev, regmap, id->name);
> +}
> +
> +static const struct spi_device_id adxl355_spi_id[] = {
> +       { "adxl355", 0 },
> +       { }
> +};
> +
> +MODULE_DEVICE_TABLE(spi, adxl355_spi_id);
> +
> +static const struct of_device_id adxl355_of_match[] = {
> +       { .compatible = "adi,adxl355" },
> +       { },

Comma can be removed.

> +};
> +
> +MODULE_DEVICE_TABLE(of, adxl355_of_match);
> +
> +static struct spi_driver adxl355_spi_driver = {
> +       .driver = {
> +               .name   = "adxl355_spi",
> +               .of_match_table = adxl355_of_match,
> +       },
> +       .probe          = adxl355_spi_probe,
> +       .id_table       = adxl355_spi_id,
> +};
> +
> +module_spi_driver(adxl355_spi_driver);
> +
> +MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
> +MODULE_DESCRIPTION("ADXL355 3-Axis Digital Accelerometer SPI driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.30.1
>