Re: [PATCH v6 2/2] iio: magnetometer: bmc150: use FIELD_PREP and FIELD_GET helpers

From: Jonathan Cameron

Date: Wed Jun 10 2026 - 11:46:24 EST

On Wed, 10 Jun 2026 13:58:31 +0000
Hungyu Lin <dennylin0707@xxxxxxxxx> wrote:

> Replace open-coded bitfield operations with FIELD_PREP() and
> FIELD_GET() helpers where appropriate.
>
> Also simplify bmc150_magn_set_odr() by returning directly from
> the matching table entry.
>
> Signed-off-by: Hungyu Lin <dennylin0707@xxxxxxxxx>
Andy mentioned in previous patch - slow down! More than one version a day
is very rarely appropriate. That creates a lot of noise on the list
and means that you aren't gathering up multiple bits of feedback before
posting a new verison.

Anything I apply for IIO is now 7.3 material so this isn't going upstream
for about 3 months anyway so take your time!

The alignment is not the preferred amount for pretty much all cases.
Rather than go to v7, applied but with this fix up:
Note that it is on the testing branch of iio.git which will get rebased
on rc1 once available in about 3 weeks time.

diff --git a/drivers/iio/magnetometer/bmc150_magn.c b/drivers/iio/magnetometer/bmc150_magn.c
index ee8092d4006c..32dff9cdd0f7 100644
--- a/drivers/iio/magnetometer/bmc150_magn.c
+++ b/drivers/iio/magnetometer/bmc150_magn.c
@@ -248,13 +248,13 @@ static int bmc150_magn_set_power_mode(struct bmc150_magn_data *data,
BMC150_MAGN_REG_OPMODE_ODR,
BMC150_MAGN_MASK_OPMODE,
FIELD_PREP(BMC150_MAGN_MASK_OPMODE,
- BMC150_MAGN_MODE_SLEEP));
+ BMC150_MAGN_MODE_SLEEP));
case BMC150_MAGN_POWER_MODE_NORMAL:
return regmap_update_bits(data->regmap,
BMC150_MAGN_REG_OPMODE_ODR,
BMC150_MAGN_MASK_OPMODE,
FIELD_PREP(BMC150_MAGN_MASK_OPMODE,
- BMC150_MAGN_MODE_NORMAL));
+ BMC150_MAGN_MODE_NORMAL));
}

return -EINVAL;
@@ -312,10 +312,10 @@ static int bmc150_magn_set_odr(struct bmc150_magn_data *data, int val)
continue;

return regmap_update_bits(data->regmap,
- BMC150_MAGN_REG_OPMODE_ODR,
- BMC150_MAGN_MASK_ODR,
- FIELD_PREP(BMC150_MAGN_MASK_ODR,
- bmc150_magn_samp_freq_table[i].reg_val));
+ BMC150_MAGN_REG_OPMODE_ODR,
+ BMC150_MAGN_MASK_ODR,
+ FIELD_PREP(BMC150_MAGN_MASK_ODR,
+ bmc150_magn_samp_freq_table[i].reg_val));
}

> ---
> drivers/iio/magnetometer/bmc150_magn.c | 33 ++++++++++++--------------
> 1 file changed, 15 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/iio/magnetometer/bmc150_magn.c b/drivers/iio/magnetometer/bmc150_magn.c
> index f6639d7fab04..ee8092d4006c 100644
> --- a/drivers/iio/magnetometer/bmc150_magn.c
> +++ b/drivers/iio/magnetometer/bmc150_magn.c
> @@ -9,6 +9,7 @@
> * (C) Copyright 2011~2014 Bosch Sensortec GmbH All Rights Reserved
> */
>
> +#include <linux/bitfield.h>
> #include <linux/cleanup.h>
> #include <linux/delay.h>
> #include <linux/i2c.h>
> @@ -246,14 +247,14 @@ static int bmc150_magn_set_power_mode(struct bmc150_magn_data *data,
> return regmap_update_bits(data->regmap,
> BMC150_MAGN_REG_OPMODE_ODR,
> BMC150_MAGN_MASK_OPMODE,
> - BMC150_MAGN_MODE_SLEEP <<
> - BMC150_MAGN_SHIFT_OPMODE);
> + FIELD_PREP(BMC150_MAGN_MASK_OPMODE,
> + BMC150_MAGN_MODE_SLEEP));
Should be aligned as:
FIELD_PREP(BMC150_MAGN_MASK_OPMODE,
BMC150_MAGN_MODE_SLEEP));

> case BMC150_MAGN_POWER_MODE_NORMAL:
> return regmap_update_bits(data->regmap,
> BMC150_MAGN_REG_OPMODE_ODR,
> BMC150_MAGN_MASK_OPMODE,
> - BMC150_MAGN_MODE_NORMAL <<
> - BMC150_MAGN_SHIFT_OPMODE);
> + FIELD_PREP(BMC150_MAGN_MASK_OPMODE,
> + BMC150_MAGN_MODE_NORMAL));
Same here.

> }
>
> return -EINVAL;
> @@ -291,7 +292,7 @@ static int bmc150_magn_get_odr(struct bmc150_magn_data *data, int *val)
> ret = regmap_read(data->regmap, BMC150_MAGN_REG_OPMODE_ODR, &reg_val);
> if (ret < 0)
> return ret;
> - odr_val = (reg_val & BMC150_MAGN_MASK_ODR) >> BMC150_MAGN_SHIFT_ODR;
> + odr_val = FIELD_GET(BMC150_MAGN_MASK_ODR, reg_val);
>
> for (i = 0; i < ARRAY_SIZE(bmc150_magn_samp_freq_table); i++)
> if (bmc150_magn_samp_freq_table[i].reg_val == odr_val) {
> @@ -304,21 +305,17 @@ static int bmc150_magn_get_odr(struct bmc150_magn_data *data, int *val)
>
> static int bmc150_magn_set_odr(struct bmc150_magn_data *data, int val)
> {
> - int ret;
> u8 i;
>
> for (i = 0; i < ARRAY_SIZE(bmc150_magn_samp_freq_table); i++) {
> - if (bmc150_magn_samp_freq_table[i].freq == val) {
> - ret = regmap_update_bits(data->regmap,
> - BMC150_MAGN_REG_OPMODE_ODR,
> - BMC150_MAGN_MASK_ODR,
> - bmc150_magn_samp_freq_table[i].
> - reg_val <<
> - BMC150_MAGN_SHIFT_ODR);
> - if (ret < 0)
> - return ret;
> - return 0;
> - }
> + if (bmc150_magn_samp_freq_table[i].freq != val)
> + continue;
> +
> + return regmap_update_bits(data->regmap,
> + BMC150_MAGN_REG_OPMODE_ODR,
> + BMC150_MAGN_MASK_ODR,
> + FIELD_PREP(BMC150_MAGN_MASK_ODR,
> + bmc150_magn_samp_freq_table[i].reg_val));
and here should be
return regmap_update_bits(data->regmap,
BMC150_MAGN_REG_OPMODE_ODR,
BMC150_MAGN_MASK_ODR,
FIELD_PREP(BMC150_MAGN_MASK_ODR,
bmc150_magn_samp_freq_table[i].reg_val));

> }
>
> return -EINVAL;
> @@ -801,7 +798,7 @@ static int bmc150_magn_data_rdy_trigger_set_state(struct iio_trigger *trig,
>
> ret = regmap_update_bits(data->regmap, BMC150_MAGN_REG_INT_DRDY,
> BMC150_MAGN_MASK_DRDY_EN,
> - state << BMC150_MAGN_SHIFT_DRDY_EN);
> + FIELD_PREP(BMC150_MAGN_MASK_DRDY_EN, state));
> if (ret < 0)
> return ret;
>