Re: [RESEND PATCH v5 5/5] input: joystick: Add ADC attached joystick driver.

[Paul Cercueil]

Hi Andy,

Le sam. 18 avril 2020 à 0:10, Andy Shevchenko 
<andy.shevchenko@xxxxxxxxx> a écrit :
> On Fri, Apr 17, 2020 at 11:21 PM Artur Rojek <contact@xxxxxxxxxxxxxx> 
> wrote:
> >  Add a driver for joystick devices connected to ADC controllers
> >  supporting the Industrial I/O subsystem.
>
> ...
>
> >  +#include <linux/of.h>
>
> Do you really need this? (See below as well)
>
> ...
>
> >  +               sign = 
> > (tolower(joy->chans[i].channel->scan_type.sign) == 's');
>
> Too many parentheses. But here it's up to you,
>
> ...
>
> >  +               case 2:
>
> >  +                       val = ((const u16 *)data)[i];
>
> Can't you do this in each branch below?
>
> >  +                       if (endianness == IIO_BE)
> >  +                               val = be16_to_cpu(val);
> >  +                       else if (endianness == IIO_LE)
> >  +                               val = le16_to_cpu(val);
> >  +                       break;
>
> ...
>
> >  +       device_for_each_child_node(dev, child) {
> >  +               ret = fwnode_property_read_u32(child, "reg", &i);
> >  +               if (ret || i >= num_axes) {
> >  +                       dev_err(dev, "reg invalid or missing");
> >  +                       goto err;
> >  +               }
> >  +
> >  +               if (fwnode_property_read_u32(child, "linux,code",
> >  +                                            &axes[i].code)) {
> >  +                       dev_err(dev, "linux,code invalid or 
> > missing");
> >  +                       goto err;
> >  +               }
> >  +
> >  +               if (fwnode_property_read_u32_array(child, 
> > "abs-range",
> >  +                                                  axes[i].range, 
> > 2)) {
> >  +                       dev_err(dev, "abs-range invalid or 
> > missing");
> >  +                       goto err;
> >  +               }
>
> >  +       }
> >  +
> >  +       joy->axes = axes;
> >  +
> >  +       return 0;
> >  +
> >  +err:
> >  +       fwnode_handle_put(child);
>
> >  +       return -EINVAL;
>
> Can we avoid shadowing the actual error code?
>
> ...
>
> >  +       bits = joy->chans[0].channel->scan_type.storagebits;
>
> >  +       if (!bits || (bits >> 3) > 2) {
>
> Wouldn't be clear to use simple 'bits > 16'?
>
> >  +               dev_err(dev, "Unsupported channel storage size");
> >  +               return -EINVAL;
> >  +       }
>
> ...
>
> >  +static const struct of_device_id adc_joystick_of_match[] = {
> >  +       { .compatible = "adc-joystick", },
> >  +       { },
> >  +};
> >  +MODULE_DEVICE_TABLE(of, adc_joystick_of_match);
> >  +
> >  +static struct platform_driver adc_joystick_driver = {
> >  +       .driver = {
> >  +               .name = "adc-joystick",
>
> >  +               .of_match_table = 
> > of_match_ptr(adc_joystick_of_match),
>
> Drop this a bit harmful of_match_ptr() macro. It should go with ugly
> #ifdeffery. Here you simple introduced a compiler warning.

I assume you mean #ifdef around the of_device_id + module table macro?

> On top of that, you are using device property API, OF use in this case
> is contradictory (at lest to some extend).

I don't see why. The fact that the driver can work when probed from 
platform code, doesn't mean that it shouldn't have a table to probe 
from devicetree.

-Paul

> >  +       },
> >  +       .probe = adc_joystick_probe,
> >  +};
>
> --
> With Best Regards,
> Andy Shevchenko