On 27 February 2018 at 23:54, Andy Shevchenko [off-list ref] wrote:

On Tue, Feb 27, 2018 at 4:35 AM, Baolin Wang [off-list ref] wrote:

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On 26 February 2018 at 20:02, Andy Shevchenko [off-list ref] wrote:

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On Mon, Feb 26, 2018 at 5:01 AM, Baolin Wang [off-list ref] wrote:

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On 25 February 2018 at 20:19, Andy Shevchenko [off-list ref] wrote:

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+       for (n = 0; n < chip->ngpio; n++) {
+               if (!(BIT(n) & val))

for_each_set_bit().

At some point you may need just to go across lib/ in the kernel and
see what we have there.

I've considered the for_each_set_bit(), it need one 'unsigned long'
type parameter, but we get the value from regmap is 'u32' type. So we
need one extra conversion from 'u32' to 'unsigned long' like:

unsigned long reg = val;

for_each_set_bit(n, &reg, chip->ngpio) {
        .......
}

If you like this conversion, then I can change to use
for_each_set_bit(). Thanks.

Wouldn't it work like

unsigned long val;

...regmap_read(..., &val);

?

It can not work, regmap_read() expects 'unsigned int *'.

Ah, OK, than the temporary variable is a left approach.

quoted

But I can
convert it like this:

for_each_set_bit(n, (unsigned long *)&val, chip->ngpio) {
         .......
}

No, this is a boilerplate for static analyzers and definitely UB.

OK. Thanks for pointing this issue out.

-- 
Baolin.wang
Best Regards