Hi Mark,
On 08/19/2015 09:11 PM, Mark Brown wrote:
> On Tue, Aug 18, 2015 at 11:23:54AM +0530, Kishon Vijay Abraham I wrote:
>> On Friday 14 August 2015 11:30 PM, Mark Brown wrote:
>>> On Mon, Jul 27, 2015 at 04:54:09PM +0530, Kishon Vijay Abraham I wrote:
>
>>>> is moved as a child node of syscon, vsel_reg and enable_reg has the
>>>> absolute address because of the address translation that happens while
>>>> creating device from device tree node.
>>>> So avoid using platform_get_resource and use of_get_address in order to
>>>> get only the offset (untranslated address) and populate these in
>>>> vsel_reg and enable_reg.
>
>>> This sounds like we're going in the wrong direction, we're moving from a
>>> more generic API to a firmware specific one. Why is this a good fix?
>
>> platform_get_resource can be used if we need the absolute address but here we
>> need only the offset.
>
> So substract this address from the start of the resource to get the
> offset? Or provide a wrapper function in the resource code which does
> that.
I'd be very appreciated if you have and can share any thought on
How can we get this absolute base address to substract?
Below is what we have in DT:
l4_cfg: l4@4a000000 {
compatible = "ti,dra7-l4-cfg", "simple-bus";
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x4a000000 0x22c000>;
[GS] <=== 0x4a000000 is our top level l4 base address
scm: scm@2000 {
compatible = "ti,dra7-scm-core", "simple-bus";
reg = <0x2000 0x2000>;
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x2000 0x2000>;
[GS] <=== 0x4a002000 is our scm-core base address
IORESOURCE_MEM: 0x4a002000 : 4A003FFF
scm_conf: scm_conf@0 {
compatible = "syscon", "simple-bus";
reg = <0x0 0x1400>;
#address-cells = <1>;
#size-cells = <1>;
[GS] <=== 0x4a002000 is our syscon base address
IORESOURCE_MEM: 0x4a002000 : 4A0033FF
pbias_regulator: pbias_regulator {
compatible = "ti,pbias-omap";
reg = <0xe00 0x4>;
[GS] <=== 0x4a002E00 is our pbias base address
IORESOURCE_MEM: 0x4a002E00 : 4A002E03
Here we should use reg_offset=0xE00 as input parameter for regmap APIs.
syscon = <&scm_conf>;
pbias_mmc_reg: pbias_mmc_omap5 {
regulator-name = "pbias_mmc_omap5";
regulator-min-microvolt = <1800000>;
regulator-max-microvolt = <3000000>;
};
};
scm_conf_clocks: clocks {
#address-cells = <1>;
#size-cells = <0>;
};
};
As I understood, all of_address APIs/code is designed to parse/translate
addresses in top-bottom direction, and it looks nontrivial to get any kind
of base addresses from driver's side (except of its own address), because
it will require reverse DT parsing in bottom-top direction.
Maybe I missed smth?
--
regards,
-grygorii
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