Re: [PATCH 07/10] media: rcar-fcp: Handle resets

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] media: rcar-fcp: ignored reset_control_deassert() return value in runtime PM
--

commit 35565c06b039b0484d84fa1dae3bc646e765ec43
Author: Paul Elder <paul.elder+renesas@ideasonboard.com>

media: rcar-fcp: Handle resets

On some versions of the FCP, such as the one on the X5H, reset control
is required to operate the FCP. Add support for handling resets
optionally, to continue supporting versions that do not require it.

> diff --git a/drivers/media/platform/renesas/rcar-fcp.c b/drivers/media/platform/renesas/rcar-fcp.c
> index d99b3ff976e80..15bcbbda3b853 100644
> --- a/drivers/media/platform/renesas/rcar-fcp.c
> +++ b/drivers/media/platform/renesas/rcar-fcp.c
[ ... ]
> @@ -305,11 +314,32 @@ static void rcar_fcp_remove(struct platform_device *pdev)
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> +static int fcp_pm_runtime_suspend(struct device *dev)
> +{
> +	struct rcar_fcp_device *fcp = dev_get_drvdata(dev);
> +
> +	reset_control_assert(fcp->rstc);
> +	return 0;
> +}

[Severity: Medium]
Is it safe to ignore the return value of reset_control_assert() in
fcp_pm_runtime_suspend()?

If the reset assertion fails, the error will be masked during suspend since
0 is always returned to the PM core.

> +
> +static int fcp_pm_runtime_resume(struct device *dev)
> +{
> +	struct rcar_fcp_device *fcp = dev_get_drvdata(dev);
> +
> +	reset_control_deassert(fcp->rstc);
> +	return 0;
> +}

[Severity: Medium]
Should the return value of reset_control_deassert() be checked and propagated
in fcp_pm_runtime_resume()?

If the deassertion fails during resume, the PM core and the driver will
wrongly assume the hardware is fully resumed. Subsequent register accesses
could target a device still in reset, which typically leads to invalid
data reads (0xffffffff) or bus faults.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260917-epaul-v7-3-rc1-x5h-vsp-fcp-v1-0-4c72d4e086dd@ideasonboard.com?part=7