On Tue, Aug 16, 2022 at 10:18 PM Dmitry Rokosov
[off-list ref] wrote:

MSA311 is a tri-axial, low-g accelerometer with I2C digital output for
sensitivity consumer applications. It has dynamic user-selectable full
scales range of +-2g/+-4g/+-8g/+-16g and allows acceleration measurements
with output data rates from 1Hz to 1000Hz.

This driver supports following MSA311 features:
    - IIO interface
    - Different power modes: NORMAL and SUSPEND (using pm_runtime)
    - ODR (Output Data Rate) selection
    - Scale and samp_freq selection
    - IIO triggered buffer, IIO reg access
    - NEW_DATA interrupt + trigger

Below features to be done:
    - Motion Events: ACTIVE, TAP, ORIENT, FREEFALL
    - Low Power mode

Spec: https://cdn-shop.adafruit.com/product-files/5309/MSA311-V1.1-ENG.pdf

Have you ever seen such a tag?
We have the Datasheet that is more or less established for this kind of links.

The comments below are not a big deal, though.

...

+static const struct iio_decimal_fract msa311_fs_table[] = {
+       {0, 9580}, {0, 19160}, {0, 38320}, {0, 76641}

I would still keep the trailing comma for better consistency with a style.

+};

...

+static const struct iio_decimal_fract msa311_odr_table[] = {
+       {1, 0}, {1, 950000}, {3, 900000}, {7, 810000}, {15, 630000},
+       {31, 250000}, {62, 500000}, {125, 0}, {250, 0}, {500, 0}, {1000, 0}

Ditto.

+};

...

+struct msa311_priv {
+       struct regmap *regs;
+       struct regmap_field *fields[F_MAX_FIELDS];
+
+       struct device *dev;
+       struct mutex lock;

+       char chip_name[10];

Why limit it to 10? You may use devm_kasprintf()

+       struct iio_trigger *new_data_trig;
+       struct regulator *vdd;
+};

...

+static inline int msa311_set_odr(struct msa311_priv *msa311, unsigned int odr)

Why inline?

+{
+       struct device *dev = msa311->dev;
+       unsigned int pwr_mode;

+       bool good_odr = false;

Can it be split to see the assignments together below?

+       int err;
+
+       err = regmap_field_read(msa311->fields[F_PWR_MODE], &pwr_mode);
+       if (err)
+               return err;
+
+       /* Filter bad ODR values */
+       if (pwr_mode == MSA311_PWR_MODE_NORMAL)
+               good_odr = (odr > MSA311_ODR_1_95_HZ);

else
  good_odr = false;

+       if (!good_odr) {
+               dev_err(dev,
+                       "can't set odr %u.%06uHz, not available in %s mode\n",
+                       msa311_odr_table[odr].integral,
+                       msa311_odr_table[odr].microfract,
+                       msa311_pwr_modes[pwr_mode]);
+               return -EINVAL;
+       }
+
+       return regmap_field_write(msa311->fields[F_ODR], odr);
+}

...

+       if (wait_ms < unintr_thresh_ms)
+               usleep_range(wait_ms * USEC_PER_MSEC,
+                            unintr_thresh_ms * USEC_PER_MSEC);
+       else
+               return msleep_interruptible(wait_ms) ? -EINTR : 0;

Can be refactored to simple

else if (msleep...)
  return -EINTR;

Same amount of LoCs, but more readable.

+       return 0;

...

+err:

We usually name labels after what they are doing, I don't see any
error here, but notify done. Hence,

out_notify_done:

+       iio_trigger_notify_done(indio_dev->trig);
+
+       return IRQ_HANDLED;

...

+       used = scnprintf(msa311->chip_name, sizeof(msa311->chip_name),
+                        "msa311-%hhx", partid);

How 'used' is being used?

+       return 0;
+}

...

+       const char zero_bulk[2] = {0};

0 is not needed, '{ }' will work.

...

+       /*
+        * Register powerdown deferred callback which suspends the chip
+        * after module unloaded.
+        *
+        * MSA311 should be in SUSPEND mode in the two cases:
+        * 1) When driver is loaded, but we do not have any data or
+        *    configuration requests to it (we are solving it using
+        *    autosuspend feature).
+        * 2) When driver is unloaded and device is not used (devm action is
+        *    used in this case).
+        */

...

+static struct i2c_driver msa311_driver = {
+       .driver = {
+               .name = "msa311",

+               .owner = THIS_MODULE,

Redundant.

+               .of_match_table = msa311_of_match,
+               .pm = pm_ptr(&msa311_pm_ops),
+       },
+       .probe_new      = msa311_probe,
+       .id_table       = msa311_i2c_id,
+};

-- 
With Best Regards,
Andy Shevchenko