On 02/21/2017 12:26 PM, Heiner Kallweit wrote:
> Add handling of RNG0 clock to the driver.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
> ---
> v2:
> - consider that clock is optional
> - use managed call to clk_disable_unprepare to ensure that
> cleaning up is done in the right order if driver is removed
> ---
> drivers/char/hw_random/meson-rng.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
> index 119d6984..2e23be80 100644
> --- a/drivers/char/hw_random/meson-rng.c
> +++ b/drivers/char/hw_random/meson-rng.c
> @@ -62,6 +62,7 @@
> #include <linux/slab.h>
> #include <linux/types.h>
> #include <linux/of.h>
> +#include <linux/clk.h>
>
> #define RNG_DATA 0x00
>
> @@ -69,6 +70,7 @@ struct meson_rng_data {
> void __iomem *base;
> struct platform_device *pdev;
> struct hwrng rng;
> + struct clk *core_clk;
> };
>
> static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
> @@ -81,11 +83,17 @@ static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
> return sizeof(u32);
> }
>
> +static void meson_rng_clk_disable(void *clk)
> +{
> + clk_disable_unprepare(clk);
> +}
> +
> static int meson_rng_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> struct meson_rng_data *data;
> struct resource *res;
> + int ret;
>
> data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> if (!data)
> @@ -98,6 +106,20 @@ static int meson_rng_probe(struct platform_device *pdev)
> if (IS_ERR(data->base))
> return PTR_ERR(data->base);
>
> + data->core_clk = devm_clk_get(dev, "core");
> + if (IS_ERR(data->core_clk))
> + data->core_clk = NULL;
> +
> + if (data->core_clk) {
This "if" is useless, if core_clk is NULL, this will work also.
> + ret = clk_prepare_enable(data->core_clk);
> + if (ret)
> + return ret;
> + ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
> + data->core_clk);
> + if (ret)
> + return ret;
> + }
> +
> data->rng.name = pdev->name;
> data->rng.read = meson_rng_read;
>
>
