Hi Arnd,
Thank you for the suggestion - it's exactly what we were looking for!
Regards,
Marc
Sent from my phone
> On Jan 15, 2014, at 5:10 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
>
>> On Wednesday 15 January 2014, Marc Carino wrote:
>> + gen-ctrl {
>> + compatible = "brcm,brcmstb-gen-ctrl-v1";
>> + reg = <0xf0404304 0x4
>> + 0xf0404308 0x4
>> + 0xf03e2578 0x4
>> + 0xf03e2488 0x10
>> + 0xf0452000 0x20>;
>> + };
>
> Sorry I didn't get back to you on this when we discussed the previous
> version. I'm actually less happy with this DT representation than the
> original. What I take from your description is that you have multiple
> register ranges that basically combine more-or-less random registers
> that belong into different Linux subsystems.
>
> I think the best way to deal with this is to have the "syscon" driver
> handle the multiplexing between the various drivers that need access
> to the registers. It would look something like (taking the numbers
> from your previous patch):
>
> ahb {
> ranges = <0 0xf0000000 0x1000000>; /* 16 MB remapped registers */
>
> hif-cpubuictrl: syscon@3e2400 {
> compatible = "brcm,7445-cpubioctrl", "syscon";
> reg = <0x3e2000, 0x1000>;
> };
>
> hif-continuation: syscon@45200 {
> compatible = "brcm,7445-hif-continuation", "syscon";
> reg = <0x452000, 0x1000>;
> };
>
> sun-top-ctrl: ...
> };
>
> This lets the syscon driver find and map the three register areas.
> Drivers that need access to the registers then do
>
> reset {
> compatible = "brcm,7445-reset-ctrl";
> syscon = <&sun-top-ctrl 0x300 0x100>;
> #reset-cells = <1>;
> };
>
> And then you can add a regular device driver to drivers/reset that provides
> a device_reset() API to other drivers, or a system-reset function to be
> registered as arm_pm_restart. This driver would use
> syscon_regmap_lookup_by_phandle() to get access to a regmap pointer,
> and then use either hardcoded offsets into the regmap, or get those
> offsets from numbers in the devicetree, as provided in the example
> above.
>
> Arnd
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
