Re: [PATCH v5 2/9] clk: renesas: rzg2l-cpg: Add support for critical resets

[Geert Uytterhoeven]

Hi Biju,

On Wed, 18 Mar 2026 at 09:41, Biju <biju.das.au@xxxxxxxxx> wrote:
> From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
>
> Some reset lines must remain deasserted at all times after boot, as
> asserting them would disable critical system functionality with no owning
> driver to restore them. This mirrors the existing crit_mod_clks mechanism
> which protects critical module clocks from being disabled.
>
> On RZ/G2L family SoCs, the DMA reset must be remain deasserted for routing
> some peripheral interrupts to CPU.
>
> Add crit_resets and num_crit_resets fields to struct rzg2l_cpg_info to
> allow SoC-specific data tables to declare reset IDs that must never be
> asserted.
>
> Introduce rzg2l_cpg_deassert_crit_resets() to iterate over all critical
> resets and deassert them. Call it both at probe time and during resume to
> ensure critical peripherals are held out of reset after power-on and
> suspend/resume cycles.
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

Thanks for your patch!

> --- a/drivers/clk/renesas/rzg2l-cpg.c
> +++ b/drivers/clk/renesas/rzg2l-cpg.c
> @@ -1765,6 +1765,15 @@ static int __rzg2l_cpg_assert(struct reset_controller_dev *rcdev,
>         dev_dbg(rcdev->dev, "%s id:%ld offset:0x%x\n",
>                 assert ? "assert" : "deassert", id, CLK_RST_R(reg));
>
> +       if (assert) {
> +               unsigned int i;
> +
> +               for (i = 0; i < priv->info->num_crit_resets; i++) {

for (unsigned int i = 0; ...)

> +                       if (id == priv->info->crit_resets[i])
> +                               return 0;
> +               }
> +       }
> +
>         if (!assert)
>                 value |= mask;
>         writel(value, priv->base + CLK_RST_R(reg));
> @@ -1802,6 +1811,21 @@ static int rzg2l_cpg_deassert(struct reset_controller_dev *rcdev,
>         return __rzg2l_cpg_assert(rcdev, id, false);
>  }
>
> +static int rzg2l_cpg_deassert_crit_resets(struct reset_controller_dev *rcdev,
> +                                         const struct rzg2l_cpg_info *info)
> +{
> +       unsigned int i;
> +       int ret;
> +
> +       for (i = 0; i < info->num_crit_resets; i++) {

for (unsigned int i = 0; ...)

> +               ret = rzg2l_cpg_deassert(rcdev, info->crit_resets[i]);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
>  static int rzg2l_cpg_reset(struct reset_controller_dev *rcdev,
>                            unsigned long id)
>  {

Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

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

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