On Mon, Jun 17, 2024 at 11:26 PM Anand Moon <linux.amoon@xxxxxxxxx> wrote:
>
> 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
>
Thanks for pointing that out! Will fix in v2.
> > + 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
