Re: [PATCH] crypto: exynos-rng - Remove exynos-rng driver

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Jun 10, 2026 at 03:46:54PM +0100, Peter Griffin wrote:
> Hi Eric,
> 
> On Sun, 31 May 2026 at 19:02, Eric Biggers <ebiggers@kernel.org> wrote:
> >
> > This driver has no purpose.  It doesn't feed into the Linux RNG, nor
> > does it implement the hwrng interface.  It is accessible only via the
> > "rng" algorithm type of AF_ALG, which isn't used in practice.  Everyone
> > uses either the Linux RNG, or rarely /dev/hwrng.
> >
> > Moreover, this is a PRNG whose only source of entropy is the 160-bit
> > seed the user passes in.  So this can be used only by a user who already
> > has a source of cryptographically secure random numbers, such as
> > /dev/random.  Which they can, and do, just use in the first place.
> >
> > Just remove this driver.  There's no need to keep useless code around.
> >
> > Note that the other crypto_rng drivers in drivers/crypto/ are similarly
> > unused and are being removed too.  This commit just handles exynos-rng.
> >
> > Signed-off-by: Eric Biggers <ebiggers@kernel.org>
> > ---
> 
> If the driver is being removed, should the binding documentation for
> this driver not also be deleted (see
> Documentation/devicetree/bindings/rng/samsung,exynos4-rng.yaml)?
> 
> Peter

In other discussions I've been told that devicetree bindings are
hardware descriptions that should still exist even if there is no
driver.  It doesn't make a lot of sense, but it seems to be what the
devicetree people want.  I expect there would be objections to removing
this binding.

- Eric