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. > 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/). Regards, PrasannaKumar
