On Thu, Oct 11, 2012 at 04:15:56AM +0000, Christopher Heiny wrote:
> On Thursday, October 11, 2012 02:21:53 AM you wrote:
> > On Sat, Oct 6, 2012 at 6:09 AM, Christopher Heiny <che...@synaptics.com>
> > wrote:
>
> >
> > > +
> > > +/** This is here because all those casts made for some ugly code.
> > > + */
> > > +static void u8_and(u8 *dest, u8 *target1, u8 *target2, int nbits)
> > > +{
> > > + bitmap_and((long unsigned int *) dest,
> > > + (long unsigned int *) target1,
> > > + (long unsigned int *) target2,
> > > + nbits);
> > > +}
> >
> > Hm, getting rid of unreadable casts is a valid case.
> >
> > I'll be OK with this but maybe the real solution is to introduce such
> > helpers into <linux/bitmap.h>?
>
> Hmmm. We'll give that some thought. Thought I'd like to get the RMI4
> driver nailed down, just to keep the area of change small. Once we've
> got all the kinks worked out here, we'll look at bitmap.h helpers.
The question is why you are using u8 for bitmaps instead of doing
DECALRE_BITMAP() and using it instead? Then you would not need silly
wrappers around existing APIs.
>
> >
> > (...)
> >
> > > +static int process_interrupt_requests(struct rmi_device *rmi_dev)
> > > +{
> > > + struct rmi_driver_data *data = dev_get_drvdata(&rmi_dev->dev);
> > > + struct device *dev = &rmi_dev->dev;
> > > + struct rmi_function_container *entry;
> > > + u8 irq_status[data->num_of_irq_regs];
> >
> > Looking at this...
> >
> > What does the data->num_of_irq_regs actually contain?
> >
> > I just fear that it is something constant like always 2 or always 4,
> > so there is actually, in reality, a 16 or 32 bit register hiding in there.
> >
> > In that case what you should do is to represent it as a u16 or u32 here,
> > just or the bits into a status word, and then walk over that status
> > word with something like ffs(bitword); ...
>
> Nope, it's not constant. In theory, and RMI4 based sensor can have up
> to 128 functions (in practice, it's far fewer), and each function can
> have as many as 7 interrupts. So the number of IRQ registers can vary
> from RMI4 sensor to RMI4 sensor, and needs to be computed during the
> scan of the product descriptor table.
Is it a good idea to have it on stack then? Should it be part of
rmi_device instead?
> >
> > > +#define simple_show_union_struct(regtype, propname, fmt)\
> > > +static ssize_t tricat(rmi_fn_, FNUM, _##propname##_show)(struct device
> > > *dev,\ + struct device_attribute *attr,
> > > char *buf) {\ + struct rmi_function_container *fc;\
> > > + struct FUNCTION_DATA *data;\
> > > +\
> > > + fc = to_rmi_function_container(dev);\
> > > + data = fc->data;\
> > > +\
> > > + return snprintf(buf, PAGE_SIZE, fmt,\
> > > + data->regtype.propname);\
> > > +}
> >
> > OK I see the point, but is there really no other way to do this than
> > to #define huge static inlines like these? Is it really not possible to
> > create just generic functions instead of going this far?
> >
> > (same comment for all)
>
> We tried generic functions previously, and it wound up really really ugly.
> We'd be willing to look at it again, though, since this isn't real beautiful
> either. If you've got an example implementation in mind. a pointer would
> help a great deal.
You just need to wrap around a custome structure around struct
device_attribute and then you shoudl be able to use generics. If you
look into trackpoint.c you should gett the idea.
Thanks.
--
Dmitry
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