Hi PrasannaKumar,
Le 2018-03-07 15:51, PrasannaKumar Muralidharan a écrit :
Hi Paul,
On 7 March 2018 at 04:31, Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote:
Le 2018-03-06 10:32, James Hogan a écrit :
On Mon, Sep 18, 2017 at 07:32:40PM +0530, PrasannaKumar Muralidharan
wrote:
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
<prasannatsmkumar@xxxxxxxxx>
Better late than never:
Acked-by: James Hogan <jhogan@xxxxxxxxxx>
(I presume its okay for the reg ranges to overlap, ISTR that being an
issue a few years ago, but maybe thats fixed now).
Cheers
James
What bothers me is that the CGU code has not been modified to use
regmap, so
the
registers area is actually mapped twice (once in the CGU driver, once
with
regmap).
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
discussion.
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
here.
The CGU block does have some registers after the RNG ones on the X1000
SoC,
but
I don't think they will ever be used (and if they are it won't be by
the CGU
driver).
Regards,
-Paul
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
(https://patchwork.linux-mips.org/patch/14094/).
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.
Thanks,
-Paul
