[alsa-devel] [PATCH 2/5] clk: bcm2835: enable management of PCM clock

[Geert Uytterhoeven]

On Sun, Jan 10, 2016 at 1:17 PM, Martin Sperl <kernel at martin.sperl.org> wrote:
>> On 10.01.2016, at 12:58, Mark Brown <broonie at kernel.org> wrote:
>>
>> On Sun, Jan 10, 2016 at 11:55:48AM +0100, Martin Sperl wrote:
>>
>>> So if someone with a better idea how to keep those dt-binding includes
>>> synchronized with the definitions used by the code step forward and
>>> propose a better solution how to get that implemented?
>>
>>> I guess there will be a few more occurrences of clocks that are
>>> currently not defined, which will need to get introduced in the future
>>> PWM and PCM were just the last in this series.
>>
>> Presumably just making the code not rely on having a define for the
>> number of clocks would deal with the problem (eg, using ARRAY_SIZE
>> internally).
> ARRAY_SIZE would work fine, but the code is:
>
> #include <dt-bindings/clock/bcm2835.h>
> ...
> struct bcm2835_cprman {
>         struct device *dev;
>         void __iomem *regs;
>         spinlock_t regs_lock;
>         const char *osc_name;
>
>         struct clk_onecell_data onecell;
>         struct clk *clks[BCM2835_CLOCK_COUNT];
> };
> ...
> static int bcm2835_clk_probe(struct platform_device *pdev)
> {
> ...
>         clks[BCM2835_PLLA_CORE] =
>                 bcm2835_register_pll_divider(cprman, &bcm2835_plla_core_data);
> ...
>         clks[BCM2835_CLOCK_PCM] =
>                 bcm2835_register_clock(cprman, &bcm2835_clock_pcm_data);
> ...
> }
>
> So the Array size is defined by the dt-bindings.

I wrote:
| Hence it can better be replaced (it seems to be unused in dts files, but you
| can keep the definition to be 100% sure) by an ARRAY_SIZE() in the C driver.
| This requires changing the driver to e.g. initialize clks[] in
|bcm2835_clk_probe() based on a table instead of explicit code.

If you fill in clks[] from a static table, you can take ARRAY_SIZE of
the static table.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds