Re: [PATCH v2 2/2] clk: rockchip: rk3288: Handle clock tree for rk3288w

[Mylene Josserand]

Hi Geert,

On 4/1/20 6:56 PM, Geert Uytterhoeven wrote:
> Hi MylÃne,
>
> On Wed, Apr 1, 2020 at 5:35 PM MylÃne Josserand
> <mylene.josserand@xxxxxxxxxxxxx> wrote:
> > The revision rk3288w has a different clock tree about
> > "hclk_vio" clock, according to the BSP kernel code.
> >
> > This patch handles this difference by detecting which SOC it is
> > and creating the div accordingly. Because we are using
> > soc_device_match function, we need to delay the registration
> > of this clock later than others to have time to get SoC revision.
> >
> > Otherwise, because of CLK_OF_DECLARE uses, clock tree will be
> > created too soon to have time to detect SoC's revision.
> >
> > Signed-off-by: MylÃne Josserand <mylene.josserand@xxxxxxxxxxxxx>
>
> Thanks for your patch!

Thanks for your review!

> > --- a/drivers/clk/rockchip/clk-rk3288.c
> > +++ b/drivers/clk/rockchip/clk-rk3288.c
> > @@ -914,10 +923,15 @@ static struct syscore_ops rk3288_clk_syscore_ops = {
> >          .resume = rk3288_clk_resume,
> >   };
> >
> > +static const struct soc_device_attribute rk3288w[] = {
> > +       { .soc_id = "RK32xx", .revision = "RK3288w" },
> > +       { /* sentinel */ }
> > +};
> > +
> > +static struct rockchip_clk_provider *ctx;
> > +
> >   static void __init rk3288_clk_init(struct device_node *np)
> >   {
> > -       struct rockchip_clk_provider *ctx;
> > -
> >          rk3288_cru_base = of_iomap(np, 0);
> >          if (!rk3288_cru_base) {
> >                  pr_err("%s: could not map cru region\n", __func__);
> > @@ -955,3 +969,17 @@ static void __init rk3288_clk_init(struct device_node *np)
> >          rockchip_clk_of_add_provider(np, ctx);
> >   }
> >   CLK_OF_DECLARE(rk3288_cru, "rockchip,rk3288-cru", rk3288_clk_init);
> > +
> > +static int __init rk3288_hclkvio_register(void)
> > +{
>
> This function will always be called, even when running a (multi-platform)
> kernel on a non-rk3288 platform.  So you need some protection against
> that.

erg, good point, I didn't think about that.

> > +       /* Check for the rk3288w revision as clock tree is different */
> > +       if (soc_device_match(rk3288w))
> > +               rockchip_clk_register_branches(ctx, rk3288w_hclkvio_branch,
> > +                                              ARRAY_SIZE(rk3288w_hclkvio_branch));
> > +       else
> > +               rockchip_clk_register_branches(ctx, rk3288_hclkvio_branch,
> > +                                              ARRAY_SIZE(rk3288_hclkvio_branch));
>
> Note that soc_device_match() returns a struct soc_device_attribute
> pointer.  If you would store the rockchip_clk_branch array pointer and
> size in rk3288w[...].data (i.e. a pointer to a struct containing that
> info), for both the r83288w and normal rk3288 variants, you could
> simplify this to:
>
>      attr = soc_device_match(rk3288w);
>      if (attr) {
>              struct rk3288_branch_array *p = attr->data;
>              rockchip_clk_register_branches(ctx, p->branches, p->len);
>      }
>
> That would handle the not-running-on-rk3288 issue as well.

Nice, thank you for the explanation and the code, very useful :)

Best regards,

MylÃne