[PATCH v2 2/3] ASoC: sunxi: sun4i-spdif: Resume device before kcontrol register access

[Chen-Yu Tsai]

On Fri, May 22, 2026 at 12:54 PM <phucduc.bui at gmail.com> wrote:
>
> From: bui duc phuc <phucduc.bui at gmail.com>
>
> Accessing registers while the device is runtime-suspended
> may lead to invalid hardware accesses on systems where the
> APB bus clock is gated during runtime suspend.

Did you actually reproduce the issue, or did you add the patch simply
because Sashiko mentioned it?

On sunxi, either it will hang the system because the bus transaction
got ignored, or it won't as something else enabled the clock.

And when you do add patches due to Sashiko raising an issue, please
do mention it in the commit message.

> Ensure the device is resumed before accessing registers.
>
> Signed-off-by: bui duc phuc <phucduc.bui at gmail.com>
> ---
>  sound/soc/sunxi/sun4i-spdif.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/sound/soc/sunxi/sun4i-spdif.c b/sound/soc/sunxi/sun4i-spdif.c
> index 89eccc83a130..f54eb14c9ed8 100644
> --- a/sound/soc/sunxi/sun4i-spdif.c
> +++ b/sound/soc/sunxi/sun4i-spdif.c
> @@ -428,6 +428,11 @@ static int sun4i_spdif_get_status(struct snd_kcontrol *kcontrol,
>         struct sun4i_spdif_dev *host = snd_soc_dai_get_drvdata(cpu_dai);
>         u8 *status = ucontrol->value.iec958.status;
>         unsigned int reg;
> +       int ret;
> +
> +       ret = pm_runtime_resume_and_get(cpu_dai->dev);
> +       if (ret)
> +               return ret;
>
>         scoped_guard(spinlock_irqsave, &host->lock) {
>                 regmap_read(host->regmap, SUN4I_SPDIF_TXCHSTA0, &reg);
> @@ -443,6 +448,8 @@ static int sun4i_spdif_get_status(struct snd_kcontrol *kcontrol,
>                 status[5] = (reg >> 8) & 0x3;
>         }
>
> +       pm_runtime_put(cpu_dai->dev);
> +
>         return 0;
>  }
>
> @@ -453,8 +460,13 @@ static int sun4i_spdif_set_status(struct snd_kcontrol *kcontrol,
>         struct sun4i_spdif_dev *host = snd_soc_dai_get_drvdata(cpu_dai);
>         u8 *status = ucontrol->value.iec958.status;
>         unsigned int reg;
> +       int ret;
>         bool chg0, chg1;
>
> +       ret = pm_runtime_resume_and_get(cpu_dai->dev);
> +       if (ret)
> +               return ret;
> +
>         scoped_guard(spinlock_irqsave, &host->lock) {
>                 reg = (u32)status[3] << 24;
>                 reg |= (u32)status[2] << 16;
> @@ -479,6 +491,8 @@ static int sun4i_spdif_set_status(struct snd_kcontrol *kcontrol,
>                                    SUN4I_SPDIF_TXCFG_NONAUDIO, reg);
>         }
>
> +       pm_runtime_put(cpu_dai->dev);
> +
>         return chg0 || chg1;
>  }
>
> --
> 2.43.0
>