On 15/06/18 18:40, Taniya Das wrote: > > > On 6/15/2018 5:29 PM, Amit Kucheria wrote: [...] >> A future version of the HW engine, or more likely, a firmware >> revision, will make more functionality available. Say, this needs >> access to another register or two. This will require changing the DT >> bindings. Instead, if you map the entire address space, you can just >> add offsets to the new registers. >> >> So in this case, I think you should define the following addresses >> (size 0x1400) for the two frequency domains >> >> 0x17d43000, 0x1400 (power cluster) >> 0x17d45800, 0x1400 (perf cluster) >> >> And in the driver simply add offsets as follows: >> >> #define ENABLE_OFFSET 0x0 >> #define LUT_OFFSET 0x110 >> #define PERF_DESIRED_OFFSET 0x920 >> > > The offsets could vary across versions of this IP and that is the reason > to provide them through the DT and not define any such offsets. > Just get compatibles to identify the version of the hardware if it can't be probed and detected. Please don't use DT to get the addresses of each register you use in the driver. That's neither scalable nor nice solution to the problem. -- Regards, Sudeep -- 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
