Re: [PATCH 17/17] i3c: renesas: Add runtime PM support

[Frank Li <Frank.li@nxp.com>]

On Fri, May 22, 2026 at 01:18:15PM +0300, Claudiu Beznea wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>
> On the SoCs where the Renesas I3C driver is enabled (RZ/G3S and RZ/G3E),
> the clocks of the IP are managed through a clock PM domain. To keep the
> I3C code simpler, the explicit clock handling was dropped along with the
> addition of runtime PM support, in favor of the runtime PM APIs. Only the
> code for getting tclk was preserved, as it is necessary to compute the
> I3C clock rate.
>
> All the APIs provided to the I3C subsystem through struct
> i3c_master_controller_ops are guarded with runtime PM APIs to
> enable/disable the controller at runtime.
>
> As the Renesas I3C driver implements an asynchronous transmit model by
> preparing a transfer and waiting for its completion through the ISR,
> renesas_i3c_abort_xfer() was added to disable interrupts and synchronize
> IRQs before runtime suspending the controller. For this, the interrupts
> were saved in struct renesas_i3c::irqs. Along with this,
> renesas_i3c_wait_xfer() return type was changed to unsigned long.
>
> Along with the clocks, the controller pin configuration is changed
> through the provided "sleep" pin configuration.
>
> Add runtime PM support for the Renesas I3C driver.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
>  drivers/i3c/master/renesas-i3c.c | 183 ++++++++++++++++++++++++++-----
>  1 file changed, 156 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/i3c/master/renesas-i3c.c b/drivers/i3c/master/renesas-i3c.c
> index a070db4d2440..3b9807a89b54 100644
> --- a/drivers/i3c/master/renesas-i3c.c
> +++ b/drivers/i3c/master/renesas-i3c.c
> @@ -21,7 +21,9 @@
...
>  static int renesas_i3c_probe(struct platform_device *pdev)
>  {
>  	struct renesas_i3c *i3c;
> @@ -1360,12 +1448,21 @@ static int renesas_i3c_probe(struct platform_device *pdev)
>  	if (IS_ERR(i3c->regs))
>  		return PTR_ERR(i3c->regs);
>
> -	ret = devm_clk_bulk_get_all_enabled(&pdev->dev, &i3c->clks);
> -	if (ret <= RENESAS_I3C_TCLK_IDX)
> -		return dev_err_probe(&pdev->dev, ret < 0 ? ret : -EINVAL,
> -				     "Failed to get clocks (need > %d, got %d)\n",
> -				     RENESAS_I3C_TCLK_IDX, ret);
> -	i3c->num_clks = ret;

you can still use devm_clk_bulk_get_all(), if need tclk, you iterate clks
to find 'tclk', in case in future, need more clocks than tcls.

> +	i3c->tclk = devm_clk_get(&pdev->dev, "tclk");
> +	if (IS_ERR(i3c->tclk))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(i3c->tclk), "Failed to get tclk");
> +
> +	i3c->dev = &pdev->dev;
> +	pm_runtime_set_autosuspend_delay(&pdev->dev, 300);
> +	pm_runtime_use_autosuspend(&pdev->dev);
> +	ret = devm_add_action_or_reset(&pdev->dev, renesas_i3c_dont_use_autosuspend,
> +				       i3c->dev);

do you cleanup resource in renesas_i3c_dont_use_autosuspend(), look likes
needn't it.

> +	if (ret)
> +		return ret;
> +
> +	ret = devm_pm_runtime_enable(&pdev->dev);
> +	if (ret)
> +		return ret;
>
...
>
> +static int renesas_i3c_runtime_suspend(struct device *dev)
> +{
> +	return pinctrl_pm_select_sleep_state(dev);

Only change pin state, don't disable clock?

Frank
> +}
> +
> +static int renesas_i3c_runtime_resume(struct device *dev)
> +{
> +	return pinctrl_pm_select_default_state(dev);
> +}
> +
>  static const struct dev_pm_ops renesas_i3c_pm_ops = {
> +	RUNTIME_PM_OPS(renesas_i3c_runtime_suspend, renesas_i3c_runtime_resume, NULL)
>  	SYSTEM_SLEEP_PM_OPS(renesas_i3c_suspend, renesas_i3c_resume)
>  };
>
> --
> 2.43.0
>