On Thu, Aug 22, 2013 at 03:19:00PM +0100, Lee Jones wrote:
> On Thu, 22 Aug 2013, Mark Rutland wrote:
>
> > On Tue, Aug 20, 2013 at 10:30:34AM +0100, Sascha Hauer wrote:
> > > On Tue, Aug 20, 2013 at 11:11:19AM +0200, Linus Walleij wrote:
> > > > On Thu, Jun 6, 2013 at 2:16 PM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> > > >
> > > > > +++ b/arch/arm/boot/dts/dbx5x0.dtsi
> > > > > @@ -572,6 +572,8 @@
> > > > > v-i2c-supply = <&db8500_vape_reg>;
> > > > >
> > > > > clock-frequency = <400000>;
> > > > > + clocks = <&prcc_kclk 3 3>, <&prcc_pclk 3 3>;
> > > > > + clock-names = "nmk-i2c.0", "apb_pclk";
> > >
> > > Why do most clocks in this series have the instance number in the clock
> > > names? This looks very wrong to me.
> >
> > +1. The clock names should be the input names to the unit, they
> > shouldn't vary per instance.
>
> So I just had a quick look, and it looks like they each have their own
> clock:
>
> clk = clk_reg_prcc_kclk("p1_i2c1_kclk", "i2cclk",
> clkrst1_base, BIT(2), CLK_SET_RATE_GATE);
> clk = clk_reg_prcc_kclk("p1_i2c2_kclk", "i2cclk",
> clkrst1_base, BIT(6), CLK_SET_RATE_GATE);
> clk = clk_reg_prcc_kclk("p2_i2c3_kclk", "i2cclk",
> clkrst2_base, BIT(0), CLK_SET_RATE_GATE);
> clk_register_clkdev(clk, NULL, "nmk-i2c.3");
>
> /* etc */
>
> When using the names in Device Tree it doesn't actually matter what
> you call the first clock. You can call it "fred" if you wanted and it
> would still work, but in light of the naming conventions above and the
> fact that each clock can all be controlled independently, do we still
> want to use the name of the parent clock i.e. i2cclk?
Sorry, I don't follow.
The name should be the name of the clock _input_ on the block described,
as should be listed in documentation for the i2c block. The name should
not vary with instance, and the name should not (necessarily) match the
_output_ of the provider. Surely there's documentation for the i2c block
that gives a name for the clock input(s)?
On a related note, I see that this doesn't follow the primecell clock
bindings, which seem to rely on "apb_pclk" being first in the list. I
see that other primecell device bindings don't follow that in dts or
drivers, so I'm not sure how to fix that brokenness.
Thanks,
Mark.
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