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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Mon, 27 Apr 2020 08:59:13 +0200
Message-ID: <CAMj1kXGwVZiGbsT2NwWTyka0FVZnQcmfMSeoBKD03PdC=fRZeA@mail.gmail.com>
Subject: Re: [PATCH 2/3] hwrng: cctrng - change default to n
To:     Hadar Gat <hadar.gat@arm.com>
Cc:     Matt Mackall <mpm@selenic.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Stefan Wahren <wahrenst@gmx.net>,
        Zaibo Xu <xuzaibo@huawei.com>,
        Tomer Maimon <tmaimon77@gmail.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Gilad Ben-Yossef <gilad@benyossef.com>,
        Ofir Drang <ofir.drang@arm.com>
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On Mon, 27 Apr 2020 at 07:42, Hadar Gat <hadar.gat@arm.com> wrote:
>
> For many users, the Arm CryptoCell HW is not available, so the
> default for HW_RANDOM_CCTRNG changed to n.
>
> Signed-off-by: Hadar Gat <hadar.gat@arm.com>
> ---
>  drivers/char/hw_random/Kconfig | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> index df2d001..0938d3d 100644
> --- a/drivers/char/hw_random/Kconfig
> +++ b/drivers/char/hw_random/Kconfig
> @@ -476,8 +476,8 @@ config HW_RANDOM_KEYSTONE
>
>  config HW_RANDOM_CCTRNG
>         tristate "Arm CryptoCell True Random Number Generator support"
> -       depends on HAS_IOMEM & OF
> -       default HW_RANDOM
> +       depends on HW_RANDOM & HAS_IOMEM & OF

The whole block is guarded by if HW_RANDOM, so I don't think you need
the dependency here.

> +       default n

'default n' is the default so you can just remove the line

>         help
>           This driver provides support for the True Random Number
>           Generator available in Arm TrustZone CryptoCell.
> --
> 2.7.4
>