Hi Sam,
On Tue, 18 Jun 2024 at 06:08, Sam Protsenko <semen.protsenko@xxxxxxxxxx> wrote:
>
> Some SoCs like Exynos850 might require the SSS bus clock (PCLK) to be
> enabled in order to access TRNG registers. Add and handle optional PCLK
> clock accordingly to make it possible.
>
> Signed-off-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
> ---
> drivers/char/hw_random/exynos-trng.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/hw_random/exynos-trng.c b/drivers/char/hw_random/exynos-trng.c
> index 88a5088ed34d..4520a280134c 100644
> --- a/drivers/char/hw_random/exynos-trng.c
> +++ b/drivers/char/hw_random/exynos-trng.c
> @@ -47,7 +47,8 @@
> struct exynos_trng_dev {
> struct device *dev;
> void __iomem *mem;
> - struct clk *clk;
> + struct clk *clk; /* operating clock */
> + struct clk *pclk; /* bus clock */
> struct hwrng rng;
> };
>
> @@ -141,10 +142,23 @@ static int exynos_trng_probe(struct platform_device *pdev)
> goto err_clock;
> }
>
> + trng->pclk = devm_clk_get_optional(&pdev->dev, "pclk");
Use devm_clk_get_optional_enabled to avoid clk_prepare_enable
> + if (IS_ERR(trng->pclk)) {
> + ret = dev_err_probe(&pdev->dev, PTR_ERR(trng->pclk),
> + "cannot get pclk");
> + goto err_clock;
> + }
> +
> + ret = clk_prepare_enable(trng->pclk);
> + if (ret) {
> + dev_err(&pdev->dev, "Could not enable the pclk.\n");
> + goto err_clock;
> + }
> +
> ret = clk_prepare_enable(trng->clk);
Use devm_clk_get_enabled for this clock
> if (ret) {
> dev_err(&pdev->dev, "Could not enable the clk.\n");
> - goto err_clock;
> + goto err_clock_enable;
> }
>
> ret = devm_hwrng_register(&pdev->dev, &trng->rng);
> @@ -160,6 +174,9 @@ static int exynos_trng_probe(struct platform_device *pdev)
> err_register:
> clk_disable_unprepare(trng->clk);
>
> +err_clock_enable:
> + clk_disable_unprepare(trng->pclk);
> +
> err_clock:
> pm_runtime_put_noidle(&pdev->dev);
>
> @@ -174,6 +191,7 @@ static void exynos_trng_remove(struct platform_device *pdev)
> struct exynos_trng_dev *trng = platform_get_drvdata(pdev);
>
> clk_disable_unprepare(trng->clk);
> + clk_disable_unprepare(trng->pclk);
>
> pm_runtime_put_sync(&pdev->dev);
> pm_runtime_disable(&pdev->dev);
> --
> 2.39.2
>
>
Thanks
-Anand
