Hi PrasannaKumar,

Le 2018-03-07 15:51, PrasannaKumar Muralidharan a écrit :
Hi Paul,

On 7 March 2018 at 04:31, Paul Cercueil <p...@crapouillou.net> wrote:
Le 2018-03-06 10:32, James Hogan a écrit :

On Mon, Sep 18, 2017 at 07:32:40PM +0530, PrasannaKumar Muralidharan

Add RNG node to jz4780 dtsi. This driver uses registers that are part of the register set used by Ingenic CGU driver. Use regmap in RNG driver to access its register. Create 'simple-bus' node, make CGU and RNG node as
child of it so that both the nodes are visible without changing CGU
driver code.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmku...@gmail.com>

Better late than never:
Acked-by: James Hogan <jho...@kernel.org>

(I presume its okay for the reg ranges to overlap, ISTR that being an
issue a few years ago, but maybe thats fixed now).


What bothers me is that the CGU code has not been modified to use regmap, so
registers area is actually mapped twice (once in the CGU driver, once with

One of my previous versions changed CGU code to use regmap. I got a
review comment saying that is not required
(https://patchwork.kernel.org/patch/9906889/). The points in the
comment were valid so I reverted the change. Please have a look at the

I don't know, the point of regmap is for when a register area is shared. It does not make sense to me to have one driver use regmap and not the other one.

Besides, regmap would be useful if the RNG registers were actually located
in the
middle of the register area used by the CGU driver, which is not the case
The CGU block does have some registers after the RNG ones on the X1000 SoC,
I don't think they will ever be used (and if they are it won't be by the CGU


Ingenic M200 SoC's CGU has clock and power related registers after the
RNG registers. Paul Burton suggested using regmap to expose registers
to CGU and RNG drivers

Where can I find the M200 programming manual? The M200's CGU might have some registers located after the RNG ones, but that does not mean that they will
be used by the clocks driver.


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