linux-kernel - [PATCH next] dma: Add devm_dma_request

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Message-ID: <20241220131350.544009-1-csokas.bence@prolan.hu>
Date: Fri, 20 Dec 2024 14:13:49 +0100
From: Bence Csókás <csokas.bence@...lan.hu>
To: <dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: Bence Csókás <csokas.bence@...lan.hu>, Vinod Koul
	<vkoul@...nel.org>
Subject: [PATCH next] dma: Add devm_dma_request_chan()

Expand the arsenal of devm functions for DMA
devices, this time for requesting channels.

Signed-off-by: Bence Csókás <csokas.bence@...lan.hu>
---
 drivers/dma/dmaengine.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index c1357d7f3dc6..51c41664838d 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -926,6 +926,36 @@ void dma_release_channel(struct dma_chan *chan)
 }
 EXPORT_SYMBOL_GPL(dma_release_channel);
 
+static void dmaenginem_release_channel(void *chan)
+{
+	dma_release_channel(chan);
+}
+
+/**
+ * devm_dma_request_chan - try to allocate an exclusive slave channel
+ * @dev:	pointer to client device structure
+ * @name:	slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or an error pointer.
+ *
+ * The operation is managed and will be undone on driver detach.
+ */
+
+struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name)
+{
+	struct dma_chan *chan = dma_request_chan(dev, name);
+	int ret = 0;
+
+	if (!IS_ERR(chan))
+		ret = devm_add_action_or_reset(dev, dmaenginem_release_channel, chan);
+
+	if (ret)
+		return PTR_ERR(ret);
+
+	return chan;
+}
+EXPORT_SYMBOL_GPL(devm_dma_request_chan);
+
 /**
  * dmaengine_get - register interest in dma_channels
  */
-- 
2.34.1