On Mon, Mar 02, 2015 at 04:24:44PM +0800, Chen-Yu Tsai wrote:
> Reduced Serial Bus (RSB) is an SMBus like bus used to communicate
> with some PMICs (like the AXP223) or other peripherals.
>
> The RSB DT bindings are pretty much the same as the one defined for
> the marvell's mv64xxx controller, with the additional RSB specific
> "allwinner,rsb-hw-addr" property for slave device nodes.
>
> There are 2 types of addresses for RSB devices, a hardware address
> and a runtime (software) configurable address. The former is only
> used when configuring the latter. All read/write accesses use the
> runtime address.
>
> It would seem straightforward to use the hardware address in the
> DT bindings as the slave's address. However this will not work as
> the hardware address is 12 bits wide, and at least 1 device, the
> AC100 audio codec, has the highest bit set. This address would be
> incompatible with I2C (7 or 10 bit addresses) and likely rejected.
>
> Hence this binding uses statically allocated (by the author of the
> DT) runtime addresses for the slave's "reg" property. The hardware
> address is put in a separete named property. When writing a new DT,
^ separate
> the author must take care to not have multiple slave devices use
> the same address. It is recommended to follow whatever conventions
> the hardware vendor uses.While very complete, the three last paragraphs should rather be, or at least duplicated, in the file itself. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
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