On Sun, 04 Oct 2015, Barry Song wrote:
> 2015-09-29 16:55 GMT+08:00 Lee Jones <lee.jo...@linaro.org>:
> > On Tue, 29 Sep 2015, Barry Song wrote:
> >
> >> 2015-09-29 15:16 GMT+08:00 Lee Jones <lee.jo...@linaro.org>:
> >> > On Tue, 29 Sep 2015, Barry Song wrote:
> >> >> >> >> +static int sirfsoc_pwrc_probe(struct platform_device *pdev)
> >> >> >> >> +{
> >> >> >> >> + struct device_node *np = pdev->dev.of_node;
> >> >> >> >> + const struct of_device_id *match;
> >> >> >> >> + struct sirfsoc_pwrc_info *pwrcinfo;
> >> >> >> >> + struct regmap_irq_chip *regmap_irq_chip;
> >> >> >> >> + struct sirfsoc_pwrc_register *pwrc_reg;
> >> >> >> >> + struct regmap *map;
> >> >> >> >> + int ret;
> >> >> >> >> + u32 base;
> >> >> >> >> +
> >> >> >> >> + if (of_property_read_u32(np, "reg", &base))
> >> >> >> >> + panic("unable to find base address of pwrc node in
> >> >> >> >> dtb\n");
> >> >> >> >
> >> >> >> > It looks like this driver should depend on OF.
> >> >> >> >
> >> >> >> > Why are you obtaining the base address manually? Use:
> >> >> >> >
> >> >> >> > res = platform_get_resource();
> >> >> >> > devm_ioremap_resource(res);
> >> >> >> >
> >> >> >> > ... instead.
> >> >> >>
> >> >> >> this was explained as they are not in memory space, they are behind a
> >> >> >> bus bridge.
> >> >> >
> >> >> > Use 'ranges' in the DT, then you can pull out the proper address
> >> >> > without hand rolling your own method.
> >> >>
> >> >> it seems it is not a "ranges" thing, things behind rtciobrg is much
> >> >> like things behind USB or sdio. we need to use a rtciobrg protocol to
> >> >> do read/write.
> >> >> they can not be randomly accessed by load/store, and can't be XIP.
> >> >> they don't have any ranges in CPU memory space.
> >> >
> >> > So what's the point of 'base' then? I assumed this was the base of
> >> > the IP registers which where memory mapped?
> >>
> >> just think we have a i2c device, and this i2c device has multi-functions.
> >> each function has a base of its register offset.
> >> actually, the base is the offset of 1st register.
> >
> > Does it every change, from device to device?
What I mean is ...
> yes. Lee. e.g:
>
> rtc-iobg@18840000 {
> reg = <0x18840000 0x1000>;
>
> sysrtc@2000 {
Is sysrtc always @2000, or might it be @4000 on some devices?
> compatible = "sirf,prima2-sysrtc";
> reg = <0x2000 0x100>;
> interrupts = <0 52 0>;
> };
> pwrc@3000 {
Same for pwrc?
> compatible = "sirf,atlas7-pwrc";
> reg = <0x3000 0x100>;
> interrupts = <0 32 0>;
> };
>
> }
>
>
> -barry
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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