RE: [PATCH] clk: renesas: rzg2l-cpg: Skip re-initializing MSTOPs and critical resets for s2idle

[Biju Das]

Hi Claudiu,

> -----Original Message-----
> From: Claudiu Beznea <claudiu.beznea@xxxxxxxxxx>
> Sent: 19 October 2026 13:25
> Subject: [PATCH] clk: renesas: rzg2l-cpg: Skip re-initializing MSTOPs and critical resets for s2idle
> 
> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> 
> When the system suspends to s2idle, any of the IP blocks may be in the wakeup path. For a device in the
> wakeup path, the generic PM domain (genpd) does not disable/enable its clocks across suspend/resume. Re-
> initializing the MSTOP bits for such a device leads to synchronous aborts when its registers are accessed
> for the first time after resume.
> 
> In a suspend mode that is not controlled by firmware, power to the SoC is not lost, so the MSTOP and
> critical reset state is retained and does not need re-initialization in the first place. Skip it when
> pm_suspend_via_firmware() reports such a mode.
> 
> Fixes: 5cd33db56956 ("clk: renesas: rzg2l: Add support for MSTOP in clock enable/disable API")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> ---
>  drivers/clk/renesas/rzg2l-cpg.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c index
> f6293c968bcf..3d2281456036 100644
> --- a/drivers/clk/renesas/rzg2l-cpg.c
> +++ b/drivers/clk/renesas/rzg2l-cpg.c
> @@ -31,6 +31,7 @@
>  #include <linux/reset-controller.h>
>  #include <linux/slab.h>
>  #include <linux/string_choices.h>
> +#include <linux/suspend.h>
>  #include <linux/units.h>
> 
>  #include <dt-bindings/clock/renesas-cpg-mssr.h>
> @@ -2697,6 +2698,9 @@ static int rzg2l_cpg_resume(struct device *dev)
>  	struct rzg2l_cpg_priv *priv = dev_get_drvdata(dev);
>  	int ret;
> 
> +	if (!pm_suspend_via_firmware())
> +		return 0;
> +

Please move this after deassert, otherwise it will lead to SCIF not getting console
prompt during s2idle as reset is asserted during suspend?

Cheers,
Biju

>  	ret = rzg2l_cpg_deassert_crit_resets(&priv->rcdev, priv->info);
>  	if (ret)
>  		return ret;