On Mon, Mar 23, 2020 at 12:41 PM Ivan Mikhaylov [off-list ref] wrote:

Proximity sensor driver based on light/vcnl4000.c code.
For now supports only the single on-demand measurement.

The VCNL3020 is a fully integrated proximity sensor. Fully
integrated means that the infrared emitter is included in the
package. It has 16-bit resolution. It includes a signal
processing IC and features standard I2C communication
interface. It features an interrupt function.

Thank you for a patch, my comments below.

Datasheet available at:
http://www.vishay.com/docs/84150/vcnl3020.pdf

I'm thinking that we may simple introduce new tag, called Datesheet:
to put such links.

Signed-off-by: Ivan Mikhaylov <redacted>

...

 obj-$(CONFIG_SRF08)            += srf08.o
 obj-$(CONFIG_SX9500)           += sx9500.o
 obj-$(CONFIG_VL53L0X_I2C)      += vl53l0x-i2c.o
+obj-$(CONFIG_VCNL3020)         += vcnl3020.o

Perhaps keep ordered?

...

+/*
+ * vcnl3020.c - Support for Vishay VCNL3020 proximity sensor

Using file names in themselves is a bad idea. Whenever you would
rename file (for instance, to support new sensors from the same family
in the future) you will forget (often, I see this in practice!) to
update this line.
Just drop it from here and try to avoid in the future.

+ *
+ * based on vcnl4000.c

This sounds like a continuation of previous sentence. Drop line in
between and use proper English grammar and punctuation.

+ */

...

+struct vcnl3020_data {
+       struct i2c_client *client;
+       u32 rev;

+       struct mutex vcnl3020_lock; /* for i2c operations */

Simple 'lock' is enough, the rest is dup noise.
Also, consider kernel doc format instead of odd comments.

+};

...

+static const struct i2c_device_id vcnl3020_id[] = {
+       { "vcnl3020", 0 },
+       {}
+};
+MODULE_DEVICE_TABLE(i2c, vcnl3020_id);

Can you group this with OF table below?

...

+static int32_t vcnl3020_init(struct vcnl3020_data *data)

int32_t...

+{

+       s32 rc;

...s32?!

Applies to entire code.

+       u32 led_current;
+       struct device *dev = &data->client->dev;

Reversed xmas tree order looks better.

+       rc = i2c_smbus_read_byte_data(data->client, VCNL_PROD_REV);

Can you use regmap I²C API?

+       if (rc < 0) {
+               dev_err(dev, "Error (%d) reading product revision", rc);
+               goto exit;
+       }
+

+       if (rc == VCNL3020_PROD_ID) {
+               data->rev = rc & 0xff;

This conjunction looks strange. Also, why type of rev is u32 instead of u8?

+               mutex_init(&data->vcnl3020_lock);
+       } else {
+               dev_err(dev, "Product id (%x) did not match vcnl3020 (%x)", rc,
+                       VCNL3020_PROD_ID);
+               rc = -ENODEV;
+               goto exit;
+       }
+
+       /* set led current */
+       rc = i2c_smbus_write_byte_data(data->client, VCNL_LED_CURRENT,
+                                      led_current);
+       if (rc < 0) {
+               dev_err(dev, "Error (%d) setting LED current", rc);
+               goto exit;
+       }
+
+       return 0;

+exit:
+       return rc;

Useless. Return directly.

+};

...

+       /* wait for data to become ready */
+       while (tries--) {
+               rc = i2c_smbus_read_byte_data(data->client, VCNL_COMMAND);
+               if (rc < 0)
+                       goto fail;
+               if (rc & VCNL_PS_RDY)
+                       break;
+               msleep(20); /* measurement takes up to 100 ms */
+       }

Timeout loops look more naturally in do {} while format.

  unsigned int tries = 5;
  ...

  do {
  ...
  } while (--tries);

...

+       *val = (rc & 0xff) << 8;

+       *val |= rc & 0xff;

All these conjunctions looks fishy. Why do you need them? Cant you
rely on the returned value by I²C API?

...

+fail:

Better name is 'err_unlock' or 'out_unlock'. The rule of thumb to
describe in the label what you *about to do* there.

+       mutex_unlock(&data->vcnl3020_lock);
+
+       return rc;
+}

...

+                       rc = vcnl3020_measure_proximity(data, val);
+                       if (rc < 0)

Can rc be positive? Drop all these ' < 0' in cases where it is
guaranteed not to be the case.

+                               return rc;

...

+static int32_t vcnl3020_probe(struct i2c_client *client,
+                             const struct i2c_device_id *id)

Can you switch to ->probe_new() ?

...

+       dev_info(&client->dev, "Proximity sensor, Rev: %02x\n",
+                data->rev);

Noise.

...

+       rc = devm_iio_device_register(&client->dev, indio_dev);
+       if (rc != 0)

Redundant ' != 0' part.

+               goto out;
+
+       return rc;

+out:
+       devm_iio_device_free(&client->dev, indio_dev);
+       return rc;

Managed resources are exactly for this not to be appeared in the code.

+}

...

+static const struct of_device_id vcnl3020_of_match[] = {
+       {
+               .compatible = "vishay,vcnl3020",
+       },

Missed terminator. How did you test this?

+};

--
With Best Regards,
Andy Shevchenko