[PATCH v2] char: hw_random: atmel-rng: disable TRNG during suspend
Nicolas Ferre
nicolas.ferre at atmel.com
Tue Oct 25 01:49:55 PDT 2016
Le 25/10/2016 à 02:56, Wenyou Yang a écrit :
> To fix the over consumption on the VDDCore due to the TRNG enabled,
> disable the TRNG during suspend, not only disable the user interface
> clock (which is controlled by PMC). Because the user interface clock
> is independent from any clock that may be used in the entropy source
> logic circuitry.
>
> Signed-off-by: Wenyou Yang <wenyou.yang at atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre at atmel.com>
Thanks
> ---
>
> Changes in v2:
> - Enable the user interface first, then enable the internal clock
> when resume.
>
> drivers/char/hw_random/atmel-rng.c | 24 +++++++++++++++++++++---
> 1 file changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c
> index 0fcc9e6..ae7cae5 100644
> --- a/drivers/char/hw_random/atmel-rng.c
> +++ b/drivers/char/hw_random/atmel-rng.c
> @@ -48,6 +48,16 @@ static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max,
> return 0;
> }
>
> +static void atmel_trng_enable(struct atmel_trng *trng)
> +{
> + writel(TRNG_KEY | 1, trng->base + TRNG_CR);
> +}
> +
> +static void atmel_trng_disable(struct atmel_trng *trng)
> +{
> + writel(TRNG_KEY, trng->base + TRNG_CR);
> +}
> +
> static int atmel_trng_probe(struct platform_device *pdev)
> {
> struct atmel_trng *trng;
> @@ -71,7 +81,7 @@ static int atmel_trng_probe(struct platform_device *pdev)
> if (ret)
> return ret;
>
> - writel(TRNG_KEY | 1, trng->base + TRNG_CR);
> + atmel_trng_enable(trng);
> trng->rng.name = pdev->name;
> trng->rng.read = atmel_trng_read;
>
> @@ -94,7 +104,7 @@ static int atmel_trng_remove(struct platform_device *pdev)
>
> hwrng_unregister(&trng->rng);
>
> - writel(TRNG_KEY, trng->base + TRNG_CR);
> + atmel_trng_disable(trng);
> clk_disable_unprepare(trng->clk);
>
> return 0;
> @@ -105,6 +115,7 @@ static int atmel_trng_suspend(struct device *dev)
> {
> struct atmel_trng *trng = dev_get_drvdata(dev);
>
> + atmel_trng_disable(trng);
> clk_disable_unprepare(trng->clk);
>
> return 0;
> @@ -113,8 +124,15 @@ static int atmel_trng_suspend(struct device *dev)
> static int atmel_trng_resume(struct device *dev)
> {
> struct atmel_trng *trng = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = clk_prepare_enable(trng->clk);
> + if (ret)
> + return ret;
>
> - return clk_prepare_enable(trng->clk);
> + atmel_trng_enable(trng);
> +
> + return 0;
> }
>
> static const struct dev_pm_ops atmel_trng_pm_ops = {
>
--
Nicolas Ferre
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