Re: [PATCHv2] reset: ti-rstctrl: use the reset-simple driver

* Rob Herring [off-list ref] [180308 22:27]:

On Thu, Mar 8, 2018 at 10:02 AM, Tony Lindgren [off-list ref] wrote:

quoted

In PRM, there are also registers for each interconnect device
context lost and wake-up dependencies. We don't have a driver
for that yet, it's handled by the SoC init code currently.

Regardless of having/needing a driver, you should take a stab at doing
the binding at least. It doesn't make sense to do the binding of the
child without doing the parent.

Sure, we have already partial binding documentation for
PRM at Documentation/devicetree/bindings/arm/omap/prcm.txt.
I'll take a look at updating it for the reset controller.

quoted

Unlike the binding for reset controller, the binding for
wake-up dependencies and context lost should look similar
binding to the clkctrl clock binding we have. That's because
there are tons of those registers.

quoted

quoted

+
+           gfx_rstctrl: rstctrl@4 {
+                   compatible = "ti,rstctrl";
+                   reg = <0x4 0x4>;

Anytime I see a single register in DT I worry about scaling. How many of
these in an SoC?

There are not many instances of the reset controller. There
is one register per interconnect instance for external
accelerators, so about 3 - 10 reset controller registers
per SoC.

Okay, seems a reasonable number.

However, couldn't you just have PRM node(s) and have that register as
a simple reset driver (along with anything else it handles).

We could have a driver for PRM, but I'm not sure if doing a
separate PRM driver helps much here. It seems like reset-simple
already does the job for most part and can be enhanced as
needed :)

The missing piece is how to get the extra pieces of information
to the consumer drivers.. That is the reset status and context
lost status of each device.

Regards,

Tony