Re: [PATCH v8 14/16] ARM: dts: Introduce STM32F429 MCU

On Wed, May 20, 2015 at 06:17:34PM +0200, Maxime Coquelin wrote:

Hi Arnd, Philipp,

2015-05-13 21:11 GMT+02:00 Arnd Bergmann [off-list ref]:

quoted

Ideally the binding should follow closely what is documented
in the data sheet.

Daniel and myself would like your opinion about this binding:

rcc: rcc@40023800 {
    #reset-cells = <1>;
    #clock-cells = <2>;
    compatible = "st,stm32-rcc";
    reg = <0x40023800 0x10>, <0x40023810 0x20>, <0x40023830 0x20>;
    reg-names = "clock-cfg", "reset", "clock-gates";
};

It would solve a problem Daniel is facing due to conflicting mem
region when clock and reset drivers are enabled, as both would reserve
the same region.

Also, it would make the reset driver very generic.
Doing that, we could even create a generic-reset.c driver that would
be used by STM32 and Sunxi (at least).
In the probe function, it would check the number of reg resources.
If a single resource is passed, it would take it, else it would look
the one named "reset".
The driver and bindings would be the same for the two families, and
the bindings would be backward compatible with sunxi ones.

Philip, Arnd, what do you think?

I lack a bit of context here, but I'd be very happy to use a generic
driver. As a matter of fact, the sunxi reset driver is already pretty
much there (not that it's very difficult to do).

The only thing we did that stands out a bit is that we actually need
the reset driver much earlier than the default probe, since some of
our timers are maintained in reset. We have some code to do just that
already, we just need have something similar to be on board.

Maxime (the other one)

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com