Hi,
On Thu, Apr 12, 2012 at 04:54:01PM +0300, Alexander Shishkin wrote:
> On Wed, 11 Apr 2012 15:16:03 +0300, Felipe Balbi <balbi@xxxxxx> wrote:
> > On Wed, Apr 11, 2012 at 03:14:12PM +0300, Alexander Shishkin wrote:
> > > On Wed, 11 Apr 2012 14:37:35 +0300, Felipe Balbi <balbi@xxxxxx> wrote:
> > > > On Wed, Apr 11, 2012 at 01:52:31PM +0300, Alexander Shishkin wrote:
> > > > > On Wed, 11 Apr 2012 12:54:41 +0300, Felipe Balbi <balbi@xxxxxx> wrote:
> > > > > > why do you need separate functions to read capability or operational
> > > > > > registers ? They look the same. You could just define them a little
> > > > > > differently:
> > > > > >
> > > > > > static u32 hw_read(void *base, u32 offset, u32 mask)
> > > > > > {
> > > > > > return ioread32(base + offset) & mask;
> > > > > > }
> > > > > >
> > > > > > then, when calling it you can use:
> > > > > >
> > > > > > hw_read(hw_bank.op, ADDRESS, mask);
> > > > > > hw_read(hw_bank.cap, ADDRESS, mask);
> > > > >
> > > > > That's what I've done in the "redo register access" patch. The reason I
> > > > > didn't do this here is that I wanted to change one thing at a time. It
> > > > > might make sense to squash these patches together, too.
> > > >
> > > > that patch is different. You use some extra trickery to try and guess
> > > > which base to use (operational or capability) whereas you could just
> > > > pass that as an argument.
> > >
> > > Yes, I really wanted to hide all that under the hood and let the hw_*
> > > functions deal with the register banks, it looks better to me, but I
> > > will change it to what you're suggesting, if you think it's better like
> > > that.
> >
> > to me it looks better than trying to guess which base to use. I prefer
> > explicitly passing the base address as argument.
>
> Actually, it's not so much *guessing*, we actually know which registers
> are where. Another thing is, I still want to use lookup tables as in
> "redo register access" to eliminate the ugly register definitions like
>
> #define REGISTER1 (some_global_var.lpm ? 0x10 : 0x20)
>
> and I couldn't come up with any better way for doing that.
struct my_struct {
unsigned lpm:1;
};
...
static u32 hw_read(struct my_struct *ptr, void __iomem *base,
u32 register, u32 mask)
{
u32 reg = register;
if (ptr->lpm)
reg += 0x10;
return readl(base + reg) & mask;
}
or something similar. Another way could be:
struct my_struct {
unsigned int extra_offset;
};
static u32 hw_read(struct my_struct *ptr, void __iomem *base,
u32 register, u32 mask)
{
return readl(base + reg + ptr->extra_offset) & mask;
}
...
static int __devinit probe(struct platform_device *pdev)
{
...
if (lpm)
ptr->extra_offset = 0x10;
else
ptr->extra_offset = 0x00;
...
return 0;
}
which avoids extra branches on every read/write :-p
--
balbi
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