Hi Andy,

Le mar. 19 mai 2020 à 23:43, Andy Shevchenko 
[off-list ref] a écrit :

On Sun, May 17, 2020 at 10:49 PM Artur Rojek [off-list ref] 
wrote:

quoted

 Add a driver for joystick devices connected to ADC controllers
 supporting the Industrial I/O subsystem.

...

quoted

 +static int adc_joystick_handle(const void *data, void *private)
 +{
 +       struct adc_joystick *joy = private;
 +       enum iio_endian endianness;
 +       int bytes, msb, val, i;
 +       bool sign;
 +
 +       bytes = joy->chans[0].channel->scan_type.storagebits >> 3;
 +
 +       for (i = 0; i < joy->num_chans; ++i) {
 +               endianness = 
joy->chans[i].channel->scan_type.endianness;
 +               msb = joy->chans[i].channel->scan_type.realbits - 1;

quoted

 +               sign = 
(tolower(joy->chans[i].channel->scan_type.sign) == 's');

Do we need tolower()?

I'll answer this one:

The sign can be uppercase to specify that the value is sign-extended in 
all the storage bits.

-Paul

quoted

 +
 +               switch (bytes) {
 +               case 1:
 +                       val = ((const u8 *)data)[i];
 +                       break;
 +               case 2:
 +                       if (endianness == IIO_BE)

quoted

 +                               val = be16_to_cpu(((const u16 
*)data)[i]);

Yeah, you have to provide bitwise types to satisfy sparse.
Maybe using *_to_cpup() will cure this.

quoted

 +                       else if (endianness == IIO_LE)
 +                               val = le16_to_cpu(((const u16 
*)data)[i]);
 +                       else /* IIO_CPU */
 +                               val = ((const u16 *)data)[i];
 +                       break;
 +               default:
 +                       return -EINVAL;
 +               }
 +
 +               val >>= joy->chans[i].channel->scan_type.shift;
 +               if (sign)
 +                       val = sign_extend32(val, msb);
 +               else
 +                       val &= GENMASK(msb, 0);
 +               input_report_abs(joy->input, joy->axes[i].code, 
val);
 +       }
 +
 +       input_sync(joy->input);
 +
 +       return 0;
 +}

...

quoted

 +       /* Count how many channels we got. NULL terminated. */
 +       while (joy->chans[joy->num_chans].indio_dev)
 +               joy->num_chans++;

I don't see how useful this is. Why not simple do below...

quoted

 +       bits = joy->chans[0].channel->scan_type.storagebits;
 +       if (!bits || (bits > 16)) {
 +               dev_err(dev, "Unsupported channel storage size");
 +               return -EINVAL;
 +       }
 +       for (i = 1; i < joy->num_chans; ++i)
 +               if (joy->chans[i].channel->scan_type.storagebits != 
bits) {
 +                       dev_err(dev, "Channels must have equal 
storage size");
 +                       return -EINVAL;
 +               }

...something like

  for (i = 0; joy->chans[i].indio_dev; i++) {
    bits = joy->chans[i].channel->scan_type.storagebits;
    if (bits ...) {
      ...error handling...
    }
    if (bits != joy->chans[0].channel->scan_type.storagebits) {
      ...second level of error handling...
    }
 }

...

quoted

 +static const struct of_device_id adc_joystick_of_match[] = {
 +       { .compatible = "adc-joystick", },

quoted

 +       { },

No need comma.

quoted

 +};

--
With Best Regards,
Andy Shevchenko