Re: [PATCH v3 3/8] gpio: gpio-rz: GPIO driver for Renesas RZ series

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

Hi Linus,

On Thu, Jan 19, 2017 at 10:38 AM, Linus Walleij
<linus.walleij@xxxxxxxxxx> wrote:
> On Thu, Jan 19, 2017 at 10:36 AM, Geert Uytterhoeven
> <geert@xxxxxxxxxxxxxx> wrote:
>> On Thu, Jan 19, 2017 at 10:27 AM, Linus Walleij
>> <linus.walleij@xxxxxxxxxx> wrote:
>>> On Wed, Jan 18, 2017 at 3:06 PM, Geert Uytterhoeven
>>> <geert@xxxxxxxxxxxxxx> wrote:
>>>> On Wed, Jan 18, 2017 at 2:58 PM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
>>>>>> +       gpio_chip->request = rz_gpio_request;
>>>>>> +       gpio_chip->free = rz_gpio_free;
>>>>>> +       gpio_chip->label = dev_name(&pdev->dev);
>>>>>> +       gpio_chip->parent = &pdev->dev;
>>>>>> +       gpio_chip->owner = THIS_MODULE;
>>>>>> +       gpio_chip->base = -1;
>>>>>> +       gpio_chip->ngpio = ret == 0 ? args.args[2] : RZ_GPIOS_PER_PORT;
>>>>>
>>>>> bgpio_init() will have already set this up to 16 (RZ_GPIOS_PER_PORT)
>>>>> as we pass width 2 bytes.
>>>>
>>>> Note that some banks have less than 16 GPIOs, cfr. the last value of the
>>>> gpio-ranges tuple being less than 16.
>>>
>>> Aha OK then it is fine to override this default value calculate from
>>> the register size.
>>>
>>> But for that case we should use the standard DT property
>>> ngpios described in
>>> Documentation/devicetree/bindings/gpio/gpio.txt
>>> It is for exactly this purpose.
>>
>> IC.
>>
>> Note that gpio-rcar uses the same method, switching to "ngpios" would
>> break backwards compatibility.
>
> Can we support both?

Yes we can, I guess.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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