From: Florian Fainelli Subject: Re: [PATCH 07/12] hwrng: bcm2835-rng: Manage an optional clock Date: Sat, 4 Nov 2017 10:59:32 -0700 Message-ID: References: <20171102010408.27736-1-f.fainelli@gmail.com> <20171102010408.27736-8-f.fainelli@gmail.com> <944505791.223880.1509803454887@email.1und1.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Krzysztof Kozlowski , Ray Jui , Eric Anholt , Rob Herring , Steffen Trumtrar , Harald Freudenberger , Russell King , "moderated list:BROADCOM BCM2835 ARM ARCHITECTURE" , PrasannaKumar Muralidharan , Scott Branden , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Herbert Xu , Martin Kaiser , Matt Mackall , "maintainer:BROADCOM BCM281XX/BCM11XXX/BCM216XX ARM ARCHITE..." , Mar To: Stefan Wahren Return-path: In-Reply-To: <944505791.223880.1509803454887-7tX72C7vayboQLBSYMtkGA@public.gmane.org> Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-crypto.vger.kernel.org Hi Stefan, On 11/04/2017 06:50 AM, Stefan Wahren wrote: > Hi Florian, > >> Florian Fainelli hat am 2. November 2017 um 02:04 geschrieben: >> >> >> One of the last steps before bcm63xx-rng can be eliminated is to manage >> a clock during hwrng::init and hwrng::cleanup, so fetch it in the probe >> function, and manage it during these two steps when valid. >> >> Signed-off-by: Florian Fainelli >> --- >> drivers/char/hw_random/bcm2835-rng.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c >> index ed20e0b6b7ae..35928efb52e7 100644 >> --- a/drivers/char/hw_random/bcm2835-rng.c >> +++ b/drivers/char/hw_random/bcm2835-rng.c >> @@ -15,6 +15,7 @@ >> #include >> #include >> #include >> +#include >> >> #define RNG_CTRL 0x0 >> #define RNG_STATUS 0x4 >> @@ -33,6 +34,7 @@ struct bcm2835_rng_priv { >> struct hwrng rng; >> void __iomem *base; >> bool mask_interrupts; >> + struct clk *clk; >> }; >> >> static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng) >> @@ -67,6 +69,11 @@ static int bcm2835_rng_init(struct hwrng *rng) >> { >> struct bcm2835_rng_priv *priv = to_rng_priv(rng); >> u32 val; >> + int ret; >> + >> + ret = clk_prepare_enable(priv->clk); >> + if (ret) >> + return ret; >> >> if (priv->mask_interrupts) { >> /* mask the interrupt */ >> @@ -88,6 +95,8 @@ static void bcm2835_rng_cleanup(struct hwrng *rng) >> >> /* disable rng hardware */ >> __raw_writel(0, priv->base + RNG_CTRL); >> + >> + clk_disable_unprepare(priv->clk); >> } >> >> struct bcm2835_rng_of_data { >> @@ -130,6 +139,11 @@ static int bcm2835_rng_probe(struct platform_device *pdev) >> return PTR_ERR(priv->base); >> } >> >> + /* Clock is optional on most platforms */ >> + priv->clk = devm_clk_get(dev, NULL); >> + if (IS_ERR(priv->clk)) >> + priv->clk = NULL; > > at least in case of EPROBE_DEFERED this isn't the expected behavior. Maybe we should better trigger on non-existing clock? Good point, so more like: if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -ENODEV)? -- Florian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html