Re: [PATCH 2/4] dmaengine: sh: rz-dmac: Use devm_add_action_or_reset()

[Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>]

Hi Philipp,
Thank you for your review!

On Fri, Sep 05, 2025 at 04:53:54PM +0200, Philipp Zabel wrote:
> On Fr, 2025-09-05 at 16:44 +0200, Tommaso Merciai wrote:
> > Slightly simplify rz_dmac_probe() by using devm_add_action_or_reset()
> > for reset cleanup.
> > 
> > Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> > ---
> >  drivers/dma/sh/rz-dmac.c | 13 +++++++++++--
> >  1 file changed, 11 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> > index 0b526cc4d24be..0bc11a6038383 100644
> > --- a/drivers/dma/sh/rz-dmac.c
> > +++ b/drivers/dma/sh/rz-dmac.c
> > @@ -905,6 +905,11 @@ static int rz_dmac_parse_of(struct device *dev, struct rz_dmac *dmac)
> >  	return rz_dmac_parse_of_icu(dev, dmac);
> >  }
> >  
> > +static void rz_dmac_reset_control_assert(void *data)
> > +{
> > +	reset_control_assert(data);
> > +}
> > +
> >  static int rz_dmac_probe(struct platform_device *pdev)
> >  {
> >  	const char *irqname = "error";
> > @@ -977,6 +982,12 @@ static int rz_dmac_probe(struct platform_device *pdev)
> >  	if (ret)
> >  		goto err_pm_runtime_put;
> >  
> > +	ret = devm_add_action_or_reset(&pdev->dev,
> > +				       rz_dmac_reset_control_assert,
> > +				       dmac->rstc);
> > +	if (ret)
> > +		goto err_pm_runtime_put;
> > +
> >  	for (i = 0; i < dmac->n_channels; i++) {
> >  		ret = rz_dmac_chan_probe(dmac, &dmac->channels[i], i);
> >  		if (ret < 0)
> > @@ -1031,7 +1042,6 @@ static int rz_dmac_probe(struct platform_device *pdev)
> >  				  channel->lmdesc.base_dma);
> >  	}
> >  
> > -	reset_control_assert(dmac->rstc);
> >  err_pm_runtime_put:
> >  	pm_runtime_put(&pdev->dev);
> >  
> > @@ -1053,7 +1063,6 @@ static void rz_dmac_remove(struct platform_device *pdev)
> >  				  channel->lmdesc.base,
> >  				  channel->lmdesc.base_dma);
> >  	}
> > -	reset_control_assert(dmac->rstc);
> 
> This patch changes cleanup order by effectively moving the
> reset_control_assert() after pm_runtime_put(). The commit message does
> not explain that this is safe to do.

Agreed. Thanks.

> 
> If this is ok, I'd move the reset_control_assert() up before
> pm_runtime_enable/resume_and_get().

You mean having in the end the following calls:

...
	dmac->rstc = devm_reset_control_array_get_optional_exclusive(&pdev->dev);
	if (IS_ERR(dmac->rstc))
		return dev_err_probe(&pdev->dev, PTR_ERR(dmac->rstc),
				     "failed to get resets\n");

	ret = reset_control_deassert(dmac->rstc);
	if (ret)
		return dev_err_probe(&pdev->dev, ret,
				     "failed to deassert resets\n");

	ret = devm_add_action_or_reset(&pdev->dev,
				       rz_dmac_reset_control_assert,
				       dmac->rstc);
	if (ret)
		return dev_err_probe(&pdev->dev, ret,
				     "failed to register reset cleanup action\n");

	ret = devm_pm_runtime_enable(&pdev->dev);
	if (ret < 0)
		return dev_err_probe(&pdev->dev, ret,
				     "Failed to enable runtime PM\n");
...

Right?
Thanks in advance.


Kind Regards,
Tommaso

> 
> regards
> Philipp