linux-kernel - [PATCH v6 3/3] dmaengine: altera-msgdma: add OF support

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Message-ID: <7459635ba093d87b6bf12413cf7cfe09f6e3019b.1623251990.git.olivier.dautricourt@orolia.com>
Date:   Wed, 9 Jun 2021 17:21:46 +0200
From:   Olivier Dautricourt <olivier.dautricourt@...lia.com>
To:     Rob Herring <robh+dt@...nel.org>, Vinod Koul <vkoul@...nel.org>,
        Stefan Roese <sr@...x.de>
Cc:     Olivier Dautricourt <olivier.dautricourt@...lia.com>,
        dmaengine@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v6 3/3] dmaengine: altera-msgdma: add OF support

This driver had no device tree support.

- add compatible field "altr,socfpga-msgdma"
- register dma controller with of_dma_controller_register

Reviewed-by: Stefan Roese <sr@...x.de>
Signed-off-by: Olivier Dautricourt <olivier.dautricourt@...lia.com>
---

Notes:
    Changes in v2:
        none

    Changes from v2 to v3:
        Removed CONFIG_OF #ifdef's and use if (IS_ENABLED(CONFIG_OF))
        only once.

    Changes from v3 to v4
        Reintroduce #ifdef CONFIG_OF for msgdma_match
        as it produces a unused variable warning

    Changes from v4 to v5
        - As per Rob's comments on patch 1/2:
          change compatible field from altr,msgdma to
          altr,socfpga-msgdma.
        - change commit title to fit previous commits naming
        - As per Vinod's comments:
          - use dma_get_slave_channel instead of dma_get_any_slave_channel which
            makes more sense.
          - remove if (IS_ENABLED(CONFIG_OF)) for of_dma_controller_register
            as it is taken care by the core
    v6:
        use of_dma_xlate_by_chan_id and expect the dma cell to be 0 in dt (id of
        the unique channel)
        Check ret value of of_dma_controller_register
    	-EINVAL: non-dt device on OF system
    	0 or -ENODEV: success or non-of system
    	other: fail

        call of_dma_controller_free on dettach :)

 drivers/dma/altera-msgdma.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
index 9a841ce5f0c5..0fe0676f8e1d 100644
--- a/drivers/dma/altera-msgdma.c
+++ b/drivers/dma/altera-msgdma.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/of_dma.h>

 #include "dmaengine.h"

@@ -888,6 +889,13 @@ static int msgdma_probe(struct platform_device *pdev)
 	if (ret)
 		goto fail;

+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 of_dma_xlate_by_chan_id, dma_dev);
+	if (ret == -EINVAL)
+		dev_warn(&pdev->dev, "device was not probed from DT");
+	else if (ret && ret != -ENODEV)
+		goto fail;
+
 	dev_notice(&pdev->dev, "Altera mSGDMA driver probe success\n");

 	return 0;
@@ -908,6 +916,8 @@ static int msgdma_remove(struct platform_device *pdev)
 {
 	struct msgdma_device *mdev = platform_get_drvdata(pdev);

+	if (pdev->dev.of_node)
+		of_dma_controller_free(pdev->dev.of_node);
 	dma_async_device_unregister(&mdev->dmadev);
 	msgdma_dev_remove(mdev);

@@ -916,9 +926,19 @@ static int msgdma_remove(struct platform_device *pdev)
 	return 0;
 }

+#ifdef CONFIG_OF
+static const struct of_device_id msgdma_match[] = {
+	{ .compatible = "altr,socfpga-msgdma", },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, msgdma_match);
+#endif
+
 static struct platform_driver msgdma_driver = {
 	.driver = {
 		.name = "altera-msgdma",
+		.of_match_table = of_match_ptr(msgdma_match),
 	},
 	.probe = msgdma_probe,
 	.remove = msgdma_remove,
--
2.31.0.rc2


--
Olivier Dautricourt