Re: [PATCH v2 4/5] clk: cygnus: add clock support for Broadcom Cygnus

Arnd Bergmann
2015-01-07T09:12:07Z

On Tuesday 06 January 2015 18:29:07 Ray Jui wrote:
> On 1/6/2015 12:21 PM, Arnd Bergmann wrote:
> > On Monday 05 January 2015 15:21:15 Ray Jui wrote:
> >
> > The tables look fairly regular. Is it possible that it's common
> > to all iproc variants with a standard way to derive all other
> > values from the channel index?
> >
> Ah no. Not only it's different between different iproc variants, it's
> also different between plls on the same soc.

Ok, I see.

> >> +static const struct iproc_asiu_gate asiu_gate[BCM_CYGNUS_NUM_ASIU_CLKS] = {
> >> + [BCM_CYGNUS_ASIU_KEYPAD_CLK] =
> >> + asiu_gate_val(0x0, 7),
> >> + [BCM_CYGNUS_ASIU_ADC_CLK] =
> >> + asiu_gate_val(0x0, 9),
> >> + [BCM_CYGNUS_ASIU_PWM_CLK] =
> >> + asiu_gate_val(IPROC_CLK_INVALID_OFFSET, 0),
> >> +};
> >
> > Here I think a better binding would be to pass the gate value in the
> > clock specifier, rather than an artificial index. That would let
> > you get rid of the BCM_CYGNUS_ASIU_KEYPAD_CLK/BCM_CYGNUS_ASIU_ADC_CLK
> > macros.
> >
> You meant to pass in both the gate register offset and its bit shift
> through the clock specifier? But isn't the current ASIU clock code much
> more consistent with the rest of the iProc clock code?

For simple devices that don't need an index macro, I would always
prefer not defining them, because they are a pain to maintain.
For a simple gate clock controller, we could compute both the offset
and bit number from a single integer.

However, I now saw upon taking a closer look that the asiu has both
a gate and a divider, and the latter one is not as simple, so
my comment doesn't apply here.

Arnd