Hi Biju,
Thank you for the patch.
On Thu, Aug 25, 2022 at 02:21:41PM +0100, Biju Das wrote:
> As the resets DT property is mandatory, and is present in all .dtsi
> in mainline, add support to perform deassert/assert using reference
> counted reset handle.
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> v12->v13:
> * Removed unused iopoll.h header file.
> * Added Rb tag from Geert.
> v11->v12:
> * Replaced read_poll_timeout_atomic-> udelay(1) as testing on RZ/G1N
> shows this delay is sufficient to avoid lock-up.
> * Removed Rb tags.
> v10->v11:
> * To avoid lock-up on R-Car Gen2, added poll for reset status after deassert.
> v9->v10:
> * Moved {deassert,assert} calls to vsp1_pm_runtime_{resume,suspend}
> v8->v9:
> * No change
> v7->v8:
> * No Change
> v6->v7:
> * No change
> v5->v6:
> * Rebased to media_staging and updated commit header
> * Added Rb tag from Laurent
> * Added forward declaration for struct reset_control
> * Updated vsp1_device_get() with changes suggested by Laurent
> * Updated error message for reset_control_get form ctrl->control.
> v4->v5:
> * Added Rb tag from Geert
> v3->v4:
> * Restored error check for pm_runtime_resume_and_get and calls
> assert() in case of failure.
> v2->v3:
> * Added Rb tag from Philipp
> * If reset_control_deassert() failed, return ret directly.
> v1->v2:
> * Used reference counted reset handle to perform deassert/assert
> RFC->v1:
> * Added reset support as separate patch
> * Moved rstc just after the bus_master field in struct vsp1_device
> RFC:
> * https://patchwork.kernel.org/project/linux-renesas-soc/patch/20220112174612.10773-21-biju.das.jz@xxxxxxxxxxxxxx/
> ---
> drivers/media/platform/renesas/vsp1/vsp1.h | 2 ++
> .../media/platform/renesas/vsp1/vsp1_drv.c | 28 +++++++++++++++++--
> 2 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/renesas/vsp1/vsp1.h b/drivers/media/platform/renesas/vsp1/vsp1.h
> index 37cf33c7e6ca..baf898d577ec 100644
> --- a/drivers/media/platform/renesas/vsp1/vsp1.h
> +++ b/drivers/media/platform/renesas/vsp1/vsp1.h
> @@ -22,6 +22,7 @@
> struct clk;
> struct device;
> struct rcar_fcp_device;
> +struct reset_control;
>
> struct vsp1_drm;
> struct vsp1_entity;
> @@ -79,6 +80,7 @@ struct vsp1_device {
> void __iomem *mmio;
> struct rcar_fcp_device *fcp;
> struct device *bus_master;
> + struct reset_control *rstc;
>
> struct vsp1_brx *brs;
> struct vsp1_brx *bru;
> diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drv.c b/drivers/media/platform/renesas/vsp1/vsp1_drv.c
> index 1f73c48eb738..975e6851735e 100644
> --- a/drivers/media/platform/renesas/vsp1/vsp1_drv.c
> +++ b/drivers/media/platform/renesas/vsp1/vsp1_drv.c
> @@ -16,6 +16,7 @@
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> #include <linux/videodev2.h>
>
> #include <media/rcar-fcp.h>
> @@ -622,6 +623,7 @@ static int __maybe_unused vsp1_pm_runtime_suspend(struct device *dev)
> struct vsp1_device *vsp1 = dev_get_drvdata(dev);
>
> rcar_fcp_disable(vsp1->fcp);
> + reset_control_assert(vsp1->rstc);
>
> return 0;
> }
> @@ -631,13 +633,30 @@ static int __maybe_unused vsp1_pm_runtime_resume(struct device *dev)
> struct vsp1_device *vsp1 = dev_get_drvdata(dev);
> int ret;
>
> + ret = reset_control_deassert(vsp1->rstc);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * On R-Car Gen2, vsp1 register access after deassert can cause
> + * lock-up. It is a special case and needs some delay to avoid
> + * this lock-up.
You can reflow this to 80 columns:
* On R-Car Gen2, vsp1 register access after deassert can cause lock-up.
* It is a special case and needs some delay to avoid this lock-up.
> + */
> + udelay(1);
Is it worth conditioning this on the VSP version to only add the delay
on Gen2 ?
With these two small issues addressed,
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> +
> if (vsp1->info) {
> ret = vsp1_device_init(vsp1);
> if (ret < 0)
> - return ret;
> + goto done;
> }
>
> - return rcar_fcp_enable(vsp1->fcp);
> + ret = rcar_fcp_enable(vsp1->fcp);
> +
> +done:
> + if (ret < 0)
> + reset_control_assert(vsp1->rstc);
> +
> + return ret;
> }
>
> static const struct dev_pm_ops vsp1_pm_ops = {
> @@ -825,6 +844,11 @@ static int vsp1_probe(struct platform_device *pdev)
> if (irq < 0)
> return irq;
>
> + vsp1->rstc = devm_reset_control_get_shared(&pdev->dev, NULL);
> + if (IS_ERR(vsp1->rstc))
> + return dev_err_probe(&pdev->dev, PTR_ERR(vsp1->rstc),
> + "failed to get reset control\n");
> +
> /* FCP (optional). */
> fcp_node = of_parse_phandle(pdev->dev.of_node, "renesas,fcp", 0);
> if (fcp_node) {
--
Regards,
Laurent Pinchart
