Re: [PATCH 2/3] soc: rockchip: power-domain: Use of_clk_get_parent_count() instead of open coding

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Mike,

On Sun, Feb 18, 2018 at 8:09 PM, Michael Turquette
<mturquette@baylibre.com> wrote:
> On Sat, Feb 10, 2018 at 8:35 AM, Heiko Stuebner <heiko@sntech.de> wrote:
>> Am Freitag, 19. Januar 2018, 16:18:20 CET schrieb Geert Uytterhoeven:
>>> As of_clk_get_parent_count() returns zero on failure, while
>>> of_count_phandle_with_args() might return a negative error code, this
>>> also fixes the issue of possibly using a negative number in the
>>> allocation below.
>>>
>>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
>>> ---
>>>  drivers/soc/rockchip/pm_domains.c | 3 ++-
>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/soc/rockchip/pm_domains.c b/drivers/soc/rockchip/pm_domains.c
>>> index 5c342167b9db7a16..9936038d38771784 100644
>>> --- a/drivers/soc/rockchip/pm_domains.c
>>> +++ b/drivers/soc/rockchip/pm_domains.c
>>> @@ -16,6 +16,7 @@
>>>  #include <linux/of_address.h>
>>>  #include <linux/of_platform.h>
>>>  #include <linux/clk.h>
>>> +#include <linux/clk-provider.h>
>>
>> not wanting to be to nitpicky, but clk-provider.h seems that it should be
>> used from drivers exposing clocks to the system, not from clock users.
>>
>> I just remember that in the past clk maintainers tried to keep their
>> layering intact, so I've included them for clarification.
>>
>> Mike, Stephen: the power-domain driver of Rockchip socs needs
>> to toggle all clocks of domain peripherals when turning a domain
>> on or off, so has a variable list of clocks in the clocks property in dt.
>> Hence the of_count_... call which could be replaced with
>> of_clk_get_parent_count to not open-code this.
>
> Moving of_clk_get_parent_count to clk.h seems reasonable to me. It's
> more of an of-specific helper than a provider-specific helper.
>
> Anyone up to submit a patch so that this one doesn't need to include
> clk-provider.h?

I gave it a try.
Just moving of_clk_get_parent_count() from clk-provider.h to clk.h causes
breakage, as half of the clock providers using of_clk_get_parent_count()
do not include <linux/clk.h>:

    drivers/clk/at91/clk-generated.c
    drivers/clk/at91/clk-main.c
    drivers/clk/at91/clk-master.c
    drivers/clk/at91/clk-programmable.c
    drivers/clk/at91/clk-slow.c
    drivers/clk/at91/clk-smd.c
    drivers/clk/at91/clk-usb.c
    drivers/clk/at91/sckc.c
    drivers/clk/clk-axi-clkgen.c
    drivers/clk/clk-gpio.c
    drivers/clk/clk-hsdk-pll.c
    drivers/clk/h8300/clk-div.c
    drivers/clk/h8300/clk-h8s2678.c
    drivers/clk/renesas/clk-div6.c
    drivers/clk/ti/composite.c
    drivers/clk/ti/gate.c
    drivers/clk/ti/mux.c

So our options are:
  1. Add #include <linux/clk.h> to each of the above,
  2. Add #include <linux/clk.h> to <linux/clk-provider.h>,
  3. Do nothing, i.e. users of of_clk_get_parent_count () need to
      #include <linux/clk-provider.h>, cfr. this patch series.

Any preference? Any option I'm missing?

Thanks!

>>>  #include <linux/regmap.h>
>>>  #include <linux/mfd/syscon.h>
>>>  #include <dt-bindings/power/rk3288-power.h>
>>> @@ -391,7 +392,7 @@ static int rockchip_pm_add_one_domain(struct rockchip_pmu *pmu,
>>>               return -EINVAL;
>>>       }
>>>
>>> -     clk_cnt = of_count_phandle_with_args(node, "clocks", "#clock-cells");
>>> +     clk_cnt = of_clk_get_parent_count(node);
>>>       pd = devm_kzalloc(pmu->dev,
>>>                         sizeof(*pd) + clk_cnt * sizeof(pd->clks[0]),
>>>                         GFP_KERNEL);
>>>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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