Re: [RFC PATCH 02/06] input/rmi4: Core files

From: Linus Walleij
Date: Thu Oct 11 2012 - 11:37:10 EST


On Thu, Oct 11, 2012 at 6:15 AM, Christopher Heiny <Cheiny@xxxxxxxxxxxxx> wrote:
> On Thursday, October 11, 2012 02:21:53 AM I wrote:

>> > +union pdt_properties {
>> > + struct {
>> > + u8 reserved_1:6;
>> > + u8 has_bsr:1;
>> > + u8 reserved_2:1;
>> > + } __attribute__((__packed__));
>> > + u8 regs[1];
>>
>> I don't understand what this union is trying to achieve.
>>
>> regs[1] does not look right considering what you're trying to
>> achieve. Since the above fields require a regs[2] (9 bits!)
>> to be stored. Maybe write out what you're trying to do here
>> so I can understand it? (If everyone else in the world gets
>> it immediately, it's maybe me that need fixing instead...)
>>
>> Apart from these remarks it's looking real nice now!
>
> I only count 8 bits there, unless there's something about
> packing I'm not aware of. Is there something else you
> found confusing about the union?

I just did bad maths, too many figured in the struct...

But consider Dmitry's suggestion that you might get rid
of this unionizing.

Yours,
Linus Walleij
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