On Thu, Jun 18, 2015 at 06:19:44PM +0800, YH Huang wrote:

On Fri, 2015-06-12 at 12:20 +0200, Thierry Reding wrote:

quoted

On Thu, May 21, 2015 at 09:29:24PM +0800, YH Huang wrote:

[...]

quoted

quoted

+#define DISP_PWM_CON_1		0x14
+#define PWM_PERIOD_MASK		0xfff
+#define PWM_PERIOD_MAX		0x00000fff

Same here. PWM_PERIOD_MAX isn't actually used anywhere, so perhaps just
drop it altogether. But see also below...

quoted

+/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */
+#define PWM_PERIOD_BIT_SHIFT	12

I wasn't very clear about this in my earlier review, so let me try to
explain why I think this is confusing. You use this as a divisor, but
you encode it as a shift. It's also PWM_PERIOD_MAX + 1, so I think it
would make more sense to drop this, keep PWM_PERIOD_MAX as above and
then replace the

	>> PWM_PERIOD_BIT_SHIFT
	
below by

	/ (PWM_PERIOD_MAX + 1)

Maybe I can change in this way:
Remove this: #define PWM_PERIOD_MAX		0x00000fff
Using ">> PWM_PERIOD_BIT_SHIFT" is faster than "/ (PWM_PERIOD_MAX + 1)"
Is this right?

The compiler should be able to optimize the division to a shift, so both
will likely result in the same code. But I don't mind much either way as
long as we don't define two symbols for essentially the same value.

Thierry
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