linux-kernel - [PATCH v2 4/4] dmaengine: stm32-dma3: introduce ddata2dev helper

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Message-ID: <20251121-dma3_improv-v2-4-76a207b13ea6@foss.st.com>
Date: Fri, 21 Nov 2025 14:36:59 +0100
From: Amelie Delaunay <amelie.delaunay@...s.st.com>
To: Vinod Koul <vkoul@...nel.org>,
        Maxime Coquelin
	<mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>
CC: <dmaengine@...r.kernel.org>, <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        Amelie Delaunay <amelie.delaunay@...s.st.com>
Subject: [PATCH v2 4/4] dmaengine: stm32-dma3: introduce ddata2dev helper

The purpose of this helper is to 'standardize' device pointer retrieval,
similar to the chan2dev() helper.
ddata2dev() helper returns the device pointer from struct dma_device stored
in stm32_dma3_ddata structure.
Device pointer from struct dma_device has been initialized with &pdev->dev,
so the ddata2dev helper returns &pdev->dev.

Signed-off-by: Amelie Delaunay <amelie.delaunay@...s.st.com>
---
 drivers/dma/stm32/stm32-dma3.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/stm32/stm32-dma3.c b/drivers/dma/stm32/stm32-dma3.c
index 29ea510fa539..84b00c436134 100644
--- a/drivers/dma/stm32/stm32-dma3.c
+++ b/drivers/dma/stm32/stm32-dma3.c
@@ -333,6 +333,11 @@ static struct device *chan2dev(struct stm32_dma3_chan *chan)
 	return &chan->vchan.chan.dev->device;
 }
 
+static struct device *ddata2dev(struct stm32_dma3_ddata *ddata)
+{
+	return ddata->dma_dev.dev;
+}
+
 static void stm32_dma3_chan_dump_reg(struct stm32_dma3_chan *chan)
 {
 	struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
@@ -1110,7 +1115,7 @@ static int stm32_dma3_alloc_chan_resources(struct dma_chan *c)
 	struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
 	int ret;
 
-	ret = pm_runtime_resume_and_get(ddata->dma_dev.dev);
+	ret = pm_runtime_resume_and_get(ddata2dev(ddata));
 	if (ret < 0)
 		return ret;
 
@@ -1144,7 +1149,7 @@ static int stm32_dma3_alloc_chan_resources(struct dma_chan *c)
 	chan->lli_pool = NULL;
 
 err_put_sync:
-	pm_runtime_put_sync(ddata->dma_dev.dev);
+	pm_runtime_put_sync(ddata2dev(ddata));
 
 	return ret;
 }
@@ -1170,7 +1175,7 @@ static void stm32_dma3_free_chan_resources(struct dma_chan *c)
 	if (chan->semaphore_mode)
 		stm32_dma3_put_chan_sem(chan);
 
-	pm_runtime_put_sync(ddata->dma_dev.dev);
+	pm_runtime_put_sync(ddata2dev(ddata));
 
 	/* Reset configuration */
 	memset(&chan->dt_config, 0, sizeof(chan->dt_config));
@@ -1610,11 +1615,11 @@ static bool stm32_dma3_filter_fn(struct dma_chan *c, void *fn_param)
 		if (!(mask & BIT(chan->id)))
 			return false;
 
-	ret = pm_runtime_resume_and_get(ddata->dma_dev.dev);
+	ret = pm_runtime_resume_and_get(ddata2dev(ddata));
 	if (ret < 0)
 		return false;
 	semcr = readl_relaxed(ddata->base + STM32_DMA3_CSEMCR(chan->id));
-	pm_runtime_put_sync(ddata->dma_dev.dev);
+	pm_runtime_put_sync(ddata2dev(ddata));
 
 	/* Check if chan is free */
 	if (semcr & CSEMCR_SEM_MUTEX)
@@ -1636,7 +1641,7 @@ static struct dma_chan *stm32_dma3_of_xlate(struct of_phandle_args *dma_spec, st
 	struct dma_chan *c;
 
 	if (dma_spec->args_count < 3) {
-		dev_err(ddata->dma_dev.dev, "Invalid args count\n");
+		dev_err(ddata2dev(ddata), "Invalid args count\n");
 		return NULL;
 	}
 
@@ -1645,14 +1650,14 @@ static struct dma_chan *stm32_dma3_of_xlate(struct of_phandle_args *dma_spec, st
 	conf.tr_conf = dma_spec->args[2];
 
 	if (conf.req_line >= ddata->dma_requests) {
-		dev_err(ddata->dma_dev.dev, "Invalid request line\n");
+		dev_err(ddata2dev(ddata), "Invalid request line\n");
 		return NULL;
 	}
 
 	/* Request dma channel among the generic dma controller list */
 	c = dma_request_channel(mask, stm32_dma3_filter_fn, &conf);
 	if (!c) {
-		dev_err(ddata->dma_dev.dev, "No suitable channel found\n");
+		dev_err(ddata2dev(ddata), "No suitable channel found\n");
 		return NULL;
 	}
 
@@ -1665,6 +1670,7 @@ static struct dma_chan *stm32_dma3_of_xlate(struct of_phandle_args *dma_spec, st
 
 static u32 stm32_dma3_check_rif(struct stm32_dma3_ddata *ddata)
 {
+	struct device *dev = ddata2dev(ddata);
 	u32 chan_reserved, mask = 0, i, ccidcfgr, invalid_cid = 0;
 
 	/* Reserve Secure channels */
@@ -1676,7 +1682,7 @@ static u32 stm32_dma3_check_rif(struct stm32_dma3_ddata *ddata)
 	 * In case CID filtering is not configured, dma-channel-mask property can be used to
 	 * specify available DMA channels to the kernel.
 	 */
-	of_property_read_u32(ddata->dma_dev.dev->of_node, "dma-channel-mask", &mask);
+	of_property_read_u32(dev->of_node, "dma-channel-mask", &mask);
 
 	/* Reserve !CID-filtered not in dma-channel-mask, static CID != CID1, CID1 not allowed */
 	for (i = 0; i < ddata->dma_channels; i++) {
@@ -1696,7 +1702,7 @@ static u32 stm32_dma3_check_rif(struct stm32_dma3_ddata *ddata)
 				ddata->chans[i].semaphore_mode = true;
 			}
 		}
-		dev_dbg(ddata->dma_dev.dev, "chan%d: %s mode, %s\n", i,
+		dev_dbg(dev, "chan%d: %s mode, %s\n", i,
 			!(ccidcfgr & CCIDCFGR_CFEN) ? "!CID-filtered" :
 			ddata->chans[i].semaphore_mode ? "Semaphore" : "Static CID",
 			(chan_reserved & BIT(i)) ? "denied" :
@@ -1704,7 +1710,7 @@ static u32 stm32_dma3_check_rif(struct stm32_dma3_ddata *ddata)
 	}
 
 	if (invalid_cid)
-		dev_warn(ddata->dma_dev.dev, "chan%*pbl have invalid CID configuration\n",
+		dev_warn(dev, "chan%*pbl have invalid CID configuration\n",
 			 ddata->dma_channels, &invalid_cid);
 
 	return chan_reserved;

-- 
2.43.0