[PATCH v2] iommu/rockchip: make clock handling optional

[Enric Balletbo Serra]

2018-04-17 14:09 GMT+02:00 Heiko Stuebner <heiko at sntech.de>:
> iommu clocks are optional, so the driver should not fail if they are not
> present. Instead just set the number of clocks to 0, which the clk-blk APIs
> can handle just fine.
>
> Fixes: f2e3a5f557ad ("iommu/rockchip: Control clocks needed to access the IOMMU")
> Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> Reviewed-by: Robin Murphy <robin.murphy at arm.com>
> ---
> changes in v2:
> - keep it required in the binding for future variants
>   but optional in the code for backwards compatiblity
> - follow Robin Murphy's beautification suggestion
>
> As the original changes breaks a lot of display support in 4.17-rc1,
> this should abviously go in as fix into 4.17.
>
>  drivers/iommu/rockchip-iommu.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
> index 5fc8656c60f9..422d22990289 100644
> --- a/drivers/iommu/rockchip-iommu.c
> +++ b/drivers/iommu/rockchip-iommu.c
> @@ -1175,8 +1175,15 @@ static int rk_iommu_probe(struct platform_device *pdev)
>         for (i = 0; i < iommu->num_clocks; ++i)
>                 iommu->clocks[i].id = rk_iommu_clocks[i];
>
> +       /*
> +        * iommu clocks should be present for all new devices and devicetrees
> +        * but there are older devicetrees without clocks out in the wild.
> +        * So clocks as optional for the time being.
> +        */
>         err = devm_clk_bulk_get(iommu->dev, iommu->num_clocks, iommu->clocks);
> -       if (err)
> +       if (err == -ENOENT)
> +               iommu->num_clocks = 0;
> +       else if (err)
>                 return err;
>
>         err = clk_bulk_prepare(iommu->num_clocks, iommu->clocks);
> --
> 2.16.2
>
>
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Thanks to this patch my display is back :)

Tested-by: Enric Balletbo i Serra <enric.balletbo at collabora.com>