[PATCH 0/4] dmaengine: sh: rz-dmac: Add system sleep PM support

[PATCH 0/4] dmaengine: sh: rz-dmac: Add system sleep PM support

[Tommaso Merciai]

Dear All,

This patch series improves runtime PM support and adds system sleep PM ops for
supporting deep sleep in the rz-dmac driver.

It also refactors the driver to use the newly added devm_pm_runtime_enable()
and rz_dmac_reset_control_assert() functions for reset cleanup handling.

Thanks & Regards,
Tommaso

Tommaso Merciai (4):
  dmaengine: sh: rz-dmac: Use devm_pm_runtime_enable()
  dmaengine: sh: rz-dmac: Use devm_add_action_or_reset()
  dmaengine: sh: rz-dmac: Refactor runtime PM handling
  dmaengine: sh: rz-dmac: Add system sleep power management

 drivers/dma/sh/rz-dmac.c | 82 ++++++++++++++++++++++++++++++++++------
 1 file changed, 70 insertions(+), 12 deletions(-)

-- 
2.43.0

[PATCH 1/4] dmaengine: sh: rz-dmac: Use devm_pm_runtime_enable()

[Tommaso Merciai]

Use devm_pm_runtime_enable() into rz_dmac_probe() and drop unnecessary
pm_runtime_disable() from rz_dmac_probe() and rz_dmac_remove().

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
---
 drivers/dma/sh/rz-dmac.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 1f687b08d6b86..0b526cc4d24be 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -963,12 +963,15 @@ static int rz_dmac_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(dmac->rstc),
 				     "failed to get resets\n");
 
-	pm_runtime_enable(&pdev->dev);
+	ret = devm_pm_runtime_enable(&pdev->dev);
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret,
+				     "Failed to enable runtime PM\n");
+
 	ret = pm_runtime_resume_and_get(&pdev->dev);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "pm_runtime_resume_and_get failed\n");
-		goto err_pm_disable;
-	}
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret,
+				     "pm_runtime_resume_and_get failed\n");
 
 	ret = reset_control_deassert(dmac->rstc);
 	if (ret)
@@ -1031,8 +1034,6 @@ static int rz_dmac_probe(struct platform_device *pdev)
 	reset_control_assert(dmac->rstc);
 err_pm_runtime_put:
 	pm_runtime_put(&pdev->dev);
-err_pm_disable:
-	pm_runtime_disable(&pdev->dev);
 
 	return ret;
 }
@@ -1054,7 +1055,6 @@ static void rz_dmac_remove(struct platform_device *pdev)
 	}
 	reset_control_assert(dmac->rstc);
 	pm_runtime_put(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
 
 	platform_device_put(dmac->icu.pdev);
 }
-- 
2.43.0

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

[Tommaso Merciai]

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);
 	pm_runtime_put(&pdev->dev);
 
 	platform_device_put(dmac->icu.pdev);
-- 
2.43.0

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

[Philipp Zabel]

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.

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

regards
Philipp

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

[Tommaso Merciai]

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

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

[Philipp Zabel]

On Fr, 2025-09-05 at 17:22 +0200, Tommaso Merciai wrote:
> 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?

Right.

regards
Philipp

[PATCH 3/4] dmaengine: sh: rz-dmac: Refactor runtime PM handling

[Tommaso Merciai]

Refactor runtime PM handling to ensure correct power management and prevent
resource leaks.  Invoke pm_runtime_get_sync() when allocating DMA channel
resources and pm_runtime_put() when freeing them.  Add pm_runtime_put() in
rz_dmac_probe() to balance the usage count during device initialization,
and remove the unnecessary pm_runtime_put() from rz_dmac_remove() to avoid
PM inconsistencies.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
---
 drivers/dma/sh/rz-dmac.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 0bc11a6038383..4ab6076f5499e 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -455,7 +455,7 @@ static int rz_dmac_alloc_chan_resources(struct dma_chan *chan)
 	if (!channel->descs_allocated)
 		return -ENOMEM;
 
-	return channel->descs_allocated;
+	return pm_runtime_get_sync(chan->device->dev);
 }
 
 static void rz_dmac_free_chan_resources(struct dma_chan *chan)
@@ -490,6 +490,8 @@ static void rz_dmac_free_chan_resources(struct dma_chan *chan)
 
 	INIT_LIST_HEAD(&channel->ld_free);
 	vchan_free_chan_resources(&channel->vc);
+
+	pm_runtime_put(chan->device->dev);
 }
 
 static struct dma_async_tx_descriptor *
@@ -1027,6 +1029,7 @@ static int rz_dmac_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "unable to register\n");
 		goto dma_register_err;
 	}
+	pm_runtime_put(&pdev->dev);
 	return 0;
 
 dma_register_err:
@@ -1063,7 +1066,6 @@ static void rz_dmac_remove(struct platform_device *pdev)
 				  channel->lmdesc.base,
 				  channel->lmdesc.base_dma);
 	}
-	pm_runtime_put(&pdev->dev);
 
 	platform_device_put(dmac->icu.pdev);
 }
-- 
2.43.0

RE: [PATCH 3/4] dmaengine: sh: rz-dmac: Refactor runtime PM handling

[Biju Das]

Hi Tommaso,

> -----Original Message-----
> From: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> Sent: 05 September 2025 15:44
> Subject: [PATCH 3/4] dmaengine: sh: rz-dmac: Refactor runtime PM handling
> 
> Refactor runtime PM handling to ensure correct power management and prevent resource leaks.  Invoke
> pm_runtime_get_sync() when allocating DMA channel resources and pm_runtime_put() when freeing them.
> Add pm_runtime_put() in
> rz_dmac_probe() to balance the usage count during device initialization, and remove the unnecessary
> pm_runtime_put() from rz_dmac_remove() to avoid PM inconsistencies.
> 
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> ---
>  drivers/dma/sh/rz-dmac.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c index 0bc11a6038383..4ab6076f5499e
> 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -455,7 +455,7 @@ static int rz_dmac_alloc_chan_resources(struct dma_chan *chan)
>  	if (!channel->descs_allocated)
>  		return -ENOMEM;
> 
> -	return channel->descs_allocated;
> +	return pm_runtime_get_sync(chan->device->dev);

I would check for pm_runtime_resume_and_get(chan->device->dev) first
If successful, still will return channel->descs_allocated to comply with API documentation
rather than returning "runtime PM status"

@device_alloc_chan_resources: allocate resources and return the
number of allocated descriptors.

Cheers,
Biju

Re: [PATCH 3/4] dmaengine: sh: rz-dmac: Refactor runtime PM handling

[Claudiu Beznea]

Hi, Tommaso,

On 9/5/25 17:44, Tommaso Merciai wrote:
> Refactor runtime PM handling to ensure correct power management and prevent
> resource leaks.  Invoke pm_runtime_get_sync() when allocating DMA channel
> resources and pm_runtime_put() when freeing them.  Add pm_runtime_put() in
> rz_dmac_probe() to balance the usage count during device initialization,
> and remove the unnecessary pm_runtime_put() from rz_dmac_remove() to avoid
> PM inconsistencies.
> 
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> ---
>   drivers/dma/sh/rz-dmac.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> index 0bc11a6038383..4ab6076f5499e 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -455,7 +455,7 @@ static int rz_dmac_alloc_chan_resources(struct dma_chan *chan)
>   	if (!channel->descs_allocated)
>   		return -ENOMEM;
>   
> -	return channel->descs_allocated;
> +	return pm_runtime_get_sync(chan->device->dev);

This looks wrong to me as, rz_dmac_alloc_chan_resources() could be 
called from the following path:

dma_request_chan() ->
   find_candidate() ->
     dma_chan_get() ->
       rz_dmac_alloc_chan_resources()

With this, the runtime PM reference counter is incremented on 
dma_request_chan() calls, when DMA consumers request DMA channels, and 
remains different than zero until the DMA channel is put. But, on 
suspend path, the runtime PM reference counter is not touched even when 
there are DMA channels requested.

Am I missing something?

Thank you,
Claudiu

[PATCH 4/4] dmaengine: sh: rz-dmac: Add system sleep power management

[Tommaso Merciai]

Add runtime and system sleep power management operations to the RZ DMAC
driver. This enables proper handling of suspend and resume sequences,
including device reset and channel re-initialization, preparing the driver
for power state transitions.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
---
 drivers/dma/sh/rz-dmac.c | 47 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 4ab6076f5499e..d849e313a7f79 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -437,6 +437,24 @@ static int rz_dmac_xfer_desc(struct rz_dmac_chan *chan)
  * DMA engine operations
  */
 
+static int rz_dmac_chan_init_all(struct rz_dmac *dmac)
+{
+	unsigned int i;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dmac->dev);
+	if (ret < 0)
+		return ret;
+
+	rz_dmac_writel(dmac, DCTRL_DEFAULT, CHANNEL_0_7_COMMON_BASE + DCTRL);
+	rz_dmac_writel(dmac, DCTRL_DEFAULT, CHANNEL_8_15_COMMON_BASE + DCTRL);
+
+	for (i = 0; i < dmac->n_channels; i++)
+		rz_dmac_ch_writel(&dmac->channels[i], CHCTRL_DEFAULT, CHCTRL, 1);
+
+	return pm_runtime_put_sync(dmac->dev);
+}
+
 static int rz_dmac_alloc_chan_resources(struct dma_chan *chan)
 {
 	struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
@@ -1070,6 +1088,34 @@ static void rz_dmac_remove(struct platform_device *pdev)
 	platform_device_put(dmac->icu.pdev);
 }
 
+static int rz_dmac_suspend(struct device *dev)
+{
+	struct rz_dmac *dmac = dev_get_drvdata(dev);
+
+	return reset_control_assert(dmac->rstc);
+}
+
+static int rz_dmac_resume(struct device *dev)
+{
+	struct rz_dmac *dmac = dev_get_drvdata(dev);
+	int ret;
+
+	ret = reset_control_deassert(dmac->rstc);
+	if (ret)
+		return ret;
+
+	return rz_dmac_chan_init_all(dmac);
+}
+
+static const struct dev_pm_ops rz_dmac_pm_ops = {
+	/*
+	 * TODO for system sleep/resume:
+	 *   - Wait for the current transfer to complete and stop the device,
+	 *   - Resume transfers, if any.
+	 */
+	SYSTEM_SLEEP_PM_OPS(rz_dmac_suspend, rz_dmac_resume)
+};
+
 static const struct of_device_id of_rz_dmac_match[] = {
 	{ .compatible = "renesas,r9a09g057-dmac", },
 	{ .compatible = "renesas,rz-dmac", },
@@ -1079,6 +1125,7 @@ MODULE_DEVICE_TABLE(of, of_rz_dmac_match);
 
 static struct platform_driver rz_dmac_driver = {
 	.driver		= {
+		.pm	= pm_sleep_ptr(&rz_dmac_pm_ops),
 		.name	= "rz-dmac",
 		.of_match_table = of_rz_dmac_match,
 	},
-- 
2.43.0

Re: [PATCH 0/4] dmaengine: sh: rz-dmac: Add system sleep PM support

[Tommaso Merciai]

On Fri, Sep 05, 2025 at 04:44:16PM +0200, Tommaso Merciai wrote:
> Dear All,
> 
> This patch series improves runtime PM support and adds system sleep PM ops for
> supporting deep sleep in the rz-dmac driver.
> 
> It also refactors the driver to use the newly added devm_pm_runtime_enable()
> and rz_dmac_reset_control_assert() functions for reset cleanup handling.

Series not tested yet on RZ/G2L or any stress test.

Thanks,
Tommaso

> 
> Thanks & Regards,
> Tommaso
> 
> Tommaso Merciai (4):
>   dmaengine: sh: rz-dmac: Use devm_pm_runtime_enable()
>   dmaengine: sh: rz-dmac: Use devm_add_action_or_reset()
>   dmaengine: sh: rz-dmac: Refactor runtime PM handling
>   dmaengine: sh: rz-dmac: Add system sleep power management
> 
>  drivers/dma/sh/rz-dmac.c | 82 ++++++++++++++++++++++++++++++++++------
>  1 file changed, 70 insertions(+), 12 deletions(-)
> 
> -- 
> 2.43.0
>