Re: [PATCH 2/6] dmaengine: sun6i: Add a quirk for additional mbus clock

Chen-Yu Tsai
2019-03-11T05:47:43Z

On Fri, Mar 8, 2019 at 12:58 AM Jernej Skrabec <jernej.skrabec@siol.net> wrote:
>
> H6 DMA controller needs additional mbus clock to be enabled.
>
> Add a quirk for it and handle it accordingly.
>
> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> ---
> drivers/dma/sun6i-dma.c | 23 ++++++++++++++++++++++-
> 1 file changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index 0cd13f17fc11..761555080325 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -129,6 +129,7 @@ struct sun6i_dma_config {
> u32 dst_burst_lengths;
> u32 src_addr_widths;
> u32 dst_addr_widths;
> + bool mbus_clk;

Nit: has_mbus_clk. Be explicit. Leave nothing to assumptions.

> };
>
> /*
> @@ -182,6 +183,7 @@ struct sun6i_dma_dev {
> struct dma_device slave;
> void __iomem *base;
> struct clk *clk;
> + struct clk *clk_mbus;
> int irq;
> spinlock_t lock;
> struct reset_control *rstc;
> @@ -1208,6 +1210,14 @@ static int sun6i_dma_probe(struct platform_device *pdev)
> return PTR_ERR(sdc->clk);
> }
>
> + if (sdc->cfg->mbus_clk) {
> + sdc->clk_mbus = devm_clk_get(&pdev->dev, "mbus");
> + if (IS_ERR(sdc->clk_mbus)) {
> + dev_err(&pdev->dev, "No mbus clock specified\n");
> + return PTR_ERR(sdc->clk_mbus);
> + }
> + }
> +
> sdc->rstc = devm_reset_control_get(&pdev->dev, NULL);
> if (IS_ERR(sdc->rstc)) {
> dev_err(&pdev->dev, "No reset controller specified\n");
> @@ -1312,11 +1322,19 @@ static int sun6i_dma_probe(struct platform_device *pdev)
> goto err_reset_assert;
> }
>
> + if (sdc->cfg->mbus_clk) {
> + ret = clk_prepare_enable(sdc->clk_mbus);

The clk API checks for NULL pointer, so you could just drop the
conditional here.

> + if (ret) {
> + dev_err(&pdev->dev, "Couldn't enable mbus clock\n");
> + goto err_clk_disable;
> + }
> + }
> +
> ret = devm_request_irq(&pdev->dev, sdc->irq, sun6i_dma_interrupt, 0,
> dev_name(&pdev->dev), sdc);
> if (ret) {
> dev_err(&pdev->dev, "Cannot request IRQ\n");
> - goto err_clk_disable;
> + goto err_mbus_clk_disable;
> }
>
> ret = dma_async_device_register(&sdc->slave);
> @@ -1341,6 +1359,8 @@ static int sun6i_dma_probe(struct platform_device *pdev)
> dma_async_device_unregister(&sdc->slave);
> err_irq_disable:
> sun6i_kill_tasklet(sdc);
> +err_mbus_clk_disable:
> + clk_disable_unprepare(sdc->clk_mbus);

Since you aren't using it here either.

ChenYu

> err_clk_disable:
> clk_disable_unprepare(sdc->clk);
> err_reset_assert:
> @@ -1359,6 +1379,7 @@ static int sun6i_dma_remove(struct platform_device *pdev)
>
> sun6i_kill_tasklet(sdc);
>
> + clk_disable_unprepare(sdc->clk_mbus);
> clk_disable_unprepare(sdc->clk);
> reset_control_assert(sdc->rstc);
>
> --
> 2.21.0
>