Re: [PATCH v4 2/2] drivers: dma: altera-msgdma: add OF support

From: Vinod Koul
Date: Mon May 10 2021 - 12:19:59 EST


On 29-04-21, 16:18, Olivier Dautricourt wrote:
> This driver had no device tree support.
>
> - add compatible field "altr,msgdma"
> - define msgdma_of_xlate, with no argument
> - register dma controller with of_dma_controller_register
>
> Signed-off-by: Olivier Dautricourt <olivier.dautricourt@xxxxxxxxxx>
> ---
>
> 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
>
> drivers/dma/altera-msgdma.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
> index 9a841ce5f0c5..7e58385facef 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"
>
> @@ -784,6 +785,14 @@ static int request_and_map(struct platform_device *pdev, const char *name,
> return 0;
> }
>
> +static struct dma_chan *msgdma_of_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct msgdma_device *d = ofdma->of_dma_data;
> +
> + return dma_get_any_slave_channel(&d->dmadev);

Interesting, why dma_get_any_slave_channel() dont you care for the right
slave channel which is required for your controller..?

> +}
> +
> /**
> * msgdma_probe - Driver probe function
> * @pdev: Pointer to the platform_device structure
> @@ -888,6 +897,16 @@ static int msgdma_probe(struct platform_device *pdev)
> if (ret)
> goto fail;
>
> + if (IS_ENABLED(CONFIG_OF)) {

no need of this, it is taken care by the core

> + ret = of_dma_controller_register(pdev->dev.of_node,
> + msgdma_of_xlate, mdev);
> + if (ret) {
> + dev_err(&pdev->dev,
> + "failed to register dma controller");
> + goto fail;
> + }
> + }
> +
> dev_notice(&pdev->dev, "Altera mSGDMA driver probe success\n");
>
> return 0;
> @@ -916,9 +935,19 @@ static int msgdma_remove(struct platform_device *pdev)
> return 0;
> }
>
> +#ifdef CONFIG_OF
> +static const struct of_device_id msgdma_match[] = {
> + { .compatible = "altr,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

--
~Vinod