From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752667AbdKDSXk (ORCPT ); Sat, 4 Nov 2017 14:23:40 -0400 Received: from mout.kundenserver.de ([212.227.126.134]:61316 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751979AbdKDSXi (ORCPT ); Sat, 4 Nov 2017 14:23:38 -0400 Date: Sat, 4 Nov 2017 19:22:34 +0100 (CET) From: Stefan Wahren To: Florian Fainelli 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" , Martin Kaiser , Herbert Xu , linux-kernel@vger.kernel.org, Matt Mackall , "maintainer:BROADCOM BCM281XX/BCM11XXX/BCM216XX ARM ARCHITE..." , Mark Rutland , "moderated list:BROADCOM BCM2835 ARM ARCHITECTURE" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Sean Wang Message-ID: <547786283.132202.1509819754396@email.1und1.de> In-Reply-To: References: <20171102010408.27736-1-f.fainelli@gmail.com> <20171102010408.27736-8-f.fainelli@gmail.com> <944505791.223880.1509803454887@email.1und1.de> Subject: Re: [PATCH 07/12] hwrng: bcm2835-rng: Manage an optional clock MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Priority: 3 Importance: Medium X-Mailer: Open-Xchange Mailer v7.8.3-Rev36 X-Originating-Client: open-xchange-appsuite X-Provags-ID: V03:K0:dTjqmNYezbIQYugdIFVdUQoduRjhaEDgzXHYUtBu0j4Q1ku8+O1 KYkwOEaxEbUjz/BaRP9biBKpbvr7B7mzbB5mAh088USTR0ZGOT6kp2NREG9/rZ+tK+9/ztr sgN+TRa3DQJxgWKm+O6XJPwdQqU78o+F4oKkUsDuUpgyyzl7GDLDiMyfFklY54vCWYUz9cP R4pHi/Ol47dXPBUMjCbmw== X-UI-Out-Filterresults: notjunk:1;V01:K0:7wk1rrch8ac=:0DwCI1i/G2vt1kqTxDiFua S9eOEuRh+X4S6ZO+KPlB8/e5DBn2ByCZPisct1R05Ac0WkGPzpOnGxoCO5gyRs2YI/Ml8zZC2 7xLnAxOvzVnpcJgscvs5IUrGUmk35uEZ9Fl4WUPwwq4ditG7iufY/J4v9DcU7vJVFwGh/DRju pYdzW58Y20TwY1DGszJAYz2NvQMnZ4eJ1WqvXxD05loeNwI+OVbfx2rSTHzYjwY5Rc1cHjOsW LMq7fRdD/1EpxmFItjs1DaaqQqOqQlKhQjL8ruCew2z+OKmgx4NQlDJjNls1WkbHrg8C5esQ5 sdaeeShPxbvm7ZsncFC3b4a1r4JU88nrDWNVegNVi3tIh6T73adljVLgRdsxmRYuGykDQqsdL 6ZTWKapTg6f8JNKsY2J6DFgSWBsvA1AbZp7yjsC/cim4tmaA+0Wqgbigr06yyWpwGjU++UnAT zKIVQO/EcvUMsyXCoXP4HA0XKM1rxLevo7TBAwVyiIsG9xkU/YPduZORSyxipuLcEzEZOmT5d ey03CG8Fi9sbd8jhYUBP/sVEXAJTAV+LrPx7xYPKLTdywiUlRZmi+aAnN9Z/d2p0SODY2uxEP DwaYhpYMu6WN4t7g3ugJ8WOOOPsXHEnE+WP1vC22b0x64+cm+Gmgn1OH9zhnbZqijJtfOjhim r7CZ6ZHGFkUnKTyWKjdIylz8D7Kbvpw8YTv9uNpLt1z6EBDI25TtXtmRyRrDqGWE7eD9OhuUP MpK6cnzK0/2wsIt03EL6DDPf2/NpJ1Yi4Io7FMV9DYYRU8QPJFoji3tkt34= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Florian Fainelli hat am 4. November 2017 um 18:59 geschrieben: > > > 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)? Unfortunately we need to return the error in all other cases. Please take a look at devm_usb_get_phy in dwc2 [1]. AFAIK we don't need to take care of ENXIO in our case. http://elixir.free-electrons.com/linux/latest/source/drivers/usb/dwc2/platform.c#L247 > > -- > Florian > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel