From: Wenyou Yang Subject: [PATCH v2] char: hw_random: atmel-rng: disable TRNG during suspend Date: Tue, 25 Oct 2016 08:56:33 +0800 Message-ID: <1477356993-27778-1-git-send-email-wenyou.yang@atmel.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , Wenyou Yang , , Nicolas Ferre , Wenyou Yang To: Herbert Xu , Matt Mackall Return-path: Received: from eusmtp01.atmel.com ([212.144.249.242]:28741 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755190AbcJYBAL (ORCPT ); Mon, 24 Oct 2016 21:00:11 -0400 Sender: linux-crypto-owner@vger.kernel.org List-ID: 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 --- 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 = { -- 2.7.4