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?
yes. Lee. e.g:
rtc-iobg@18840000 {
reg = <0x18840000 0x1000>;
sysrtc@2000 {
compatible = "sirf,prima2-sysrtc";
reg = <0x2000 0x100>;
interrupts = <0 52 0>;
};
pwrc@3000 {
compatible = "sirf,atlas7-pwrc";
reg = <0x3000 0x100>;
interrupts = <0 32 0>;
};
}
-barry
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