Re: [PATCH 01/10] clk/samsung: exynos5433: add definitions of HDMI-PHY output clocks

[Michael Turquette <mturquette@baylibre.com>]

Quoting Sylwester Nawrocki (2015-10-20 04:17:35)
> On 20/10/15 12:34, Michael Turquette wrote:
> >> diff --git a/include/dt-bindings/clock/exynos5433.h b/include/dt-bindings/clock/exynos5433.h
> >> > index 5bd80d5..4f0d566 100644
> >> > --- a/include/dt-bindings/clock/exynos5433.h
> >> > +++ b/include/dt-bindings/clock/exynos5433.h
> >> > @@ -765,7 +765,10 @@
> >> >  #define CLK_SCLK_RGB_VCLK                              109
> >> >  #define CLK_SCLK_RGB_TV_VCLK                           110
> >> >  
> >> > -#define DISP_NR_CLK                                    111
> >> > +#define CLK_PHYCLK_HDMIPHY_PIXEL_CLKO_PHY              111
> >> > +#define CLK_PHYCLK_HDMIPHY_TMDS_CLKO_PHY               112
> >> > +
> >> > +#define DISP_NR_CLK                                    113
> >
> > Why break compatibility with older DTBs?
> 
> I used to be resistant to changing those _NR_CLK defines
> in the past but then realized they are not part of the DT ABI.
> These defines are used only in drivers and affect only size
> of the provider's allocated clock array. The confusion may be
> caused by the fact that the whole header is shared by the kernel
> source and dts.
> 
> $ git grep -l _NR_CLK arch/arm/boot/dts drivers/clk/samsung/
> drivers/clk/samsung/clk-exynos-clkout.c
> drivers/clk/samsung/clk-exynos3250.c
> drivers/clk/samsung/clk-exynos4.c
> drivers/clk/samsung/clk-exynos4415.c
> drivers/clk/samsung/clk-exynos5250.c
> drivers/clk/samsung/clk-exynos5260.c
> drivers/clk/samsung/clk-exynos5410.c
> drivers/clk/samsung/clk-exynos5420.c
> drivers/clk/samsung/clk-exynos5433.c
> drivers/clk/samsung/clk-exynos5440.c
> drivers/clk/samsung/clk-exynos7.c
> 
> There is no *_NR_CLK in any dts file.
> New kernel will work will older DTB, the driver will just
> register more clocks, which will not be dereferenced anywhere
> in older dtb.

I skimmed through the code too fast. You're right, its a sentinel/max
value thing which is not part of the ABI.

Pardon the noise. Nothing to see here, move along...

Regards,
Mike

> 
> -- 
> Regards,
> Sylwester
> --
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