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SubjectRe: [PATCH v4 06/11] gpio: add support for the sl28cpld GPIO controller
Am 2020-06-05 14:00, schrieb Andy Shevchenko:
> On Fri, Jun 5, 2020 at 12:14 AM Michael Walle <michael@walle.cc> wrote:
>
>> Add support for the GPIO controller of the sl28 board management
>> controller. This driver is part of a multi-function device.
>>
>> A controller has 8 lines. There are three different flavors:
>> full-featured GPIO with interrupt support, input-only and output-only.
>
> ...
>
>> +#include <linux/of_device.h>
>
> I think also not needed.
> But wait...
>
>> + return devm_regmap_add_irq_chip_np(dev, dev_of_node(dev),
>> regmap,
>
> It seems regmap needs to be converted to use fwnode.

Mhh, this _np functions was actually part of this series in the
beginning.

>> + irq, IRQF_SHARED |
>> IRQF_ONESHOT, 0,
>> + irq_chip, &gpio->irq_data);
>
> ...
>
>> + if (!pdev->dev.parent)
>> + return -ENODEV;
>
> Are we expecting to get shot into foot? I mean why we need this check?

Can we be sure, that we always have a parent node? You are the first
which complains about this ;) There were some other comments to move
this to the beginning of the function.

>
>> + dev_id = platform_get_device_id(pdev);
>> + if (dev_id)
>> + type = dev_id->driver_data;
>
> Oh, no. In new code we don't need this. We have facilities to provide
> platform data in a form of fwnode.

Ok I'll look into that.

But I already have a question, so there are of_property_read_xx(), which
seems to be the old functions, then there is device_property_read_xx()
and
fwnode_property_read_xx(). What is the difference between the latter
two?

>
>> + else
>> + type =
>> (uintptr_t)of_device_get_match_data(&pdev->dev);
>
> So does this. device_get_match_data().
ok

>
>> + if (!type)
>> + return -ENODEV;
>
> ...
>
>> + if (irq_support &&
>
> Why do you need this flag? Can't simple IRQ number be sufficient?

I want to make sure, the is no misconfiguration. Eg. only GPIO
flavors which has irq_support set, have the additional interrupt
registers.

>
>> + device_property_read_bool(&pdev->dev,
>> "interrupt-controller")) {
>> + irq = platform_get_irq(pdev, 0);
>> + if (irq < 0)
>> + return irq;
>> +
>> + ret = sl28cpld_gpio_irq_init(&pdev->dev, gpio, regmap,
>> + base, irq);
>> + if (ret)
>> + return ret;
>> +
>> + config.irq_domain =
>> regmap_irq_get_domain(gpio->irq_data);
>> + }
>
> ...
>
>> +static const struct of_device_id sl28cpld_gpio_of_match[] = {
>
>> + { .compatible = "kontron,sl28cpld-gpio",
>> + .data = (void *)SL28CPLD_GPIO },
>> + { .compatible = "kontron,sl28cpld-gpi",
>> + .data = (void *)SL28CPLD_GPI },
>> + { .compatible = "kontron,sl28cpld-gpo",
>> + .data = (void *)SL28CPLD_GPO },
>
> All above can be twice less LOCs.

They are longer than 80 chars. Or do I miss something?

>
>> + {},
>
> No comma.

ok

>> +};
>
>
> ...
>
>> + .name = KBUILD_MODNAME,
>
> This actually not good idea in long term. File name can change and
> break an ABI.

Ahh an explanation, why this is bad. Ok makes sense, although to be
fair,
.id_table should be used for the driver name matching. I'm not sure if
this is used somewhere else, though.


--
-michael

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