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SubjectRe: [PATCH v1 10/11] watchdog: bd9576_wdt: switch to using devm_fwnode_gpiod_get()
On 9/5/22 08:21, Andy Shevchenko wrote:
> On Mon, Sep 5, 2022 at 6:13 PM Guenter Roeck <linux@roeck-us.net> wrote:
>> On 9/5/22 04:09, Andy Shevchenko wrote:
>>> On Mon, Sep 5, 2022 at 9:33 AM Dmitry Torokhov
>>> <dmitry.torokhov@gmail.com> wrote:
>
> ...
>
>>>> + count = device_property_count_u32(dev->parent, "rohm,hw-timeout-ms");
>>>> + if (count < 0 && count != -EINVAL)
>>>> + return count;
>>>> +
>>>> + if (count > 0) {
>>>
>>>> + if (count > ARRAY_SIZE(hw_margin))
>>>> + return -EINVAL;
>>>
>>> Why double check? You may move it out of the (count > 0).
>>
>> Two checks will always be needed, so I don't entirely see
>> how that would be better.
>
> But not nested. That's my point:
>
> if (count > ARRAY_SIZE())
> return ...
> if (count > 0)
> ...
>

The old code has either 1 or two checks if there is no error.
Your suggested code has always two checks. I don't see how that
is an improvement.

>>>> - if (ret == 1)
>>>> - hw_margin_max = hw_margin[0];
>>>
>>>> + ret = device_property_read_u32_array(dev->parent,
>>>> + "rohm,hw-timeout-ms",
>>>> + hw_margin, count);
>>>> + if (ret < 0)
>>>> + return ret;
>>>
>>> So, only this needs the count > 0 check since below already has it implicitly.
>>>
>> Sorry, I don't understand this comment.
>
> if (count > 0) {
> ret = device_property_read_u32_array(...);
> ...
> }
> if (count == 1)
> ...
> if (count == 2)
> ...
>
> But here it might be better to have the nested conditionals.
>

We know that count is either 1 or 2 here, so strictly speaking
if (count == 1) {
} else {
}
would be sufficient. On the other side, that depends on ARRAY_SIZE() being
exactly 2, so
if (count == 1) {
} else if (count == 2) {
}
would also make sense. Either way is fine with me. I'll leave it up
to Dmitry to decide what he wants to do.

Thanks,
Guenter

>>>> - if (ret == 2) {
>>>> - hw_margin_max = hw_margin[1];
>>>> - hw_margin_min = hw_margin[0];
>>>> + if (count == 1)
>>>> + hw_margin_max = hw_margin[0];
>>>> +
>>>> + if (count == 2) {
>>>> + hw_margin_max = hw_margin[1];
>>>> + hw_margin_min = hw_margin[0];
>>>> + }
>>>> }
>

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