On Fri, Feb 19, 2016 at 1:54 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Thursday 18 February 2016 15:27:06 Daniel Drake wrote: >> >> Having a cbus bus node with child devices does sound like it would >> reflect this particular view of the hardware design. How would we then >> represent the hwrev registers under that? >> > > The question is still how the CBUS is structured internally. > > https://github.com/endlessm/linux-meson/blob/master/arch/arm/mach-meson8b/include/mach/register.h > > seems to have a good list of registers, but it's a bit hard to > read, so I reformatted it slightly and put it up at http://pastebin.com/GrzYM7Ti > > In many cases, the register name prefix gives a good idea of what things > are. In particular, it seems that all registers numbers are between 0x1000 > and 0x2fff, which would be offsets 0x4000 through 0xbfff. > > The revisison register is in a block called ASSIST, which is mixed with two > AC3 (audio?) regions, and the only other ASSIST register that is ever > used is the ASSIST_POR_CONFIG. > > The METAL_REVISION is in the middle of some apparently all unrelated registers: > > #define PREG_ETH_REG0 0x2050 > #define PREG_ETH_REG1 0x2051 > #define PROD_TEST_REG1 0x2067 > #define PROD_TEST_REG0 0x2068 > #define METAL_REVISION 0x206a > #define ADC_TOP_MISC 0x206b > #define DPLL_TOP_MISC 0x206c > #define ANALOG_TOP_MISC 0x206d > #define AM_ANALOG_TOP_REG0 0x206e > #define AM_ANALOG_TOP_REG1 0x206f > #define PREG_STICKY_REG0 0x207c > #define PREG_STICKY_REG1 0x207d > > This still really sounds like a mixed bag to me, which should better get represented > as a syscon node, except that there are also some more structured areas in > CBUS. > > Having just the registers between METAL_REVISION and HW_REV in a syscon > is clearly wrong, as that would include the pinctrl area that already has > a driver, but would not include some other parts that want the syscon. Agree > Maybe the best way is to make it compatible with both syscon and > simple-bus and put the other nodes underneath. That is still rather > ugly, but at least it works and can be extended. This is a good idea actually. I'll prepare a patch. Thank you for having spent time on this. Cheers, -- Carlo Caione | +39.340.80.30.096 | Endless -- 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
