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

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Message-ID: <20250905144427.1840684-4-tommaso.merciai.xr@bp.renesas.com>
Date: Fri,  5 Sep 2025 16:44:19 +0200
From: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
To: tomm.merciai@...il.com
Cc: linux-renesas-soc@...r.kernel.org,
	biju.das.jz@...renesas.com,
	Tommaso Merciai <tommaso.merciai.xr@...renesas.com>,
	Vinod Koul <vkoul@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Wolfram Sang <wsa+renesas@...g-engineering.com>,
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
	Uwe Kleine-König <u.kleine-koenig@...libre.com>,
	dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
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@...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