Re: [PATCH v2 1/2] hwmon: (ucd9000) Add gpio chip interface

[Eddie James]

On 03/14/2018 01:55 PM, Guenter Roeck wrote:
> On Tue, Mar 13, 2018 at 11:13:04PM +0200, Andy Shevchenko wrote:
> > On Tue, Mar 13, 2018 at 10:59 PM, Eddie James
> > <eajames@xxxxxxxxxxxxxxxxxx> wrote:
> > > From: Christopher Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
> > >
> > > Add a struct gpio_chip and define some methods so that this device's
> > > I/O can be accessed via /sys/class/gpio.
> > > +       /*
> > > +        * Note:
> > > +        *
> > > +        * Pinmux support has not been added to the new gpio_chip.
> > > +        * This support should be added when possible given the mux
> > > +        * behavior of these IO devices.
> > > +        */
> > > +       data->gpio.label = (const char *)&client->name;
> > Hmm... Why do you need this casting?
> >
> > > +       data->gpio.get_direction = ucd9000_gpio_get_direction;
> > > +       data->gpio.direction_input = ucd9000_gpio_direction_input;
> > > +       data->gpio.direction_output = ucd9000_gpio_direction_output;
> > > +       data->gpio.get = ucd9000_gpio_get;
> > > +       data->gpio.set = ucd9000_gpio_set;
> > > +       data->gpio.can_sleep = 1;
> > Isn't it type of boolean?
> You are right.
>
> > > +       data->gpio.base = -1;
> > > +       data->gpio.parent = &client->dev;
> > > +       data->gpio.owner = THIS_MODULE;
> > > +       data->gpio.of_node = client->dev.of_node;
> > I think GPIO core does this for you.
> Same here. I checked and found that it also sets the owner, so maybe this can be
> dropped as well.

Ah true. Especially since there is a TODO: remove chip->owner in the core.

> > > +       if (data->gpio.ngpio) {
> > Hmm...
> >
> > I would rather reorganize the above part to a separate helper, like
> >
> > static int ..._probe_gpio()
> > {
> > ...
> >    switch () {
> >     default:
> >       return 0; /* GPIO part is optional */
> >    }
> >    return 0;
> > }
> >
> > ret = _probe_gpio();
> > if (ret)
> >   dev_warn();
> I am neutral to positiva on that.
> Might as well add the call to devm_gpiochip_add_data()
> into that function as well.

Sure. I can do a v4.

Thanks,
Eddie

> > > +               ret = devm_gpiochip_add_data(&client->dev, &data->gpio,
> > > +                                            client);
> > > +               if (ret)
> > > +                       dev_warn(&client->dev, "Could not add gpiochip: %d\n",
> > > +                                ret);
> > > +       }
> > > +
> > >          return pmbus_do_probe(client, mid, info);
> > >   }
> > >
> > > --
> > > 1.8.3.1
> >
> >
> > --
> > With Best Regards,
> > Andy Shevchenko