On 22.05.2014 14:25, Sylwester Nawrocki wrote: > On 22/05/14 14:01, Tomasz Figa wrote: >>>>>>>> [ ... ] >>>>>>>> >>>>>>>>>> + clkout->clk_table[0] = clk_register_composite(NULL, "clkout", >>>>>>>>>> + parent_names, parent_count, &clkout->mux.hw, >>>>>>>>>> + &clk_mux_ops, NULL, NULL, &clkout->gate.hw, >>>>>>>>>> + &clk_gate_ops, CLK_SET_RATE_PARENT >>>>>>>>>> + | CLK_SET_RATE_NO_REPARENT); >>>>>>>> >>>>>>>> Would you please remove CLK_SET_RATE_NO_REPARENT flag from here? Let me >>>>>>>> know if you have reservations against this. >>>>>> >>>>>> The problem with clock reparenting is that there are certain parent >>>>>> clocks of CLKOUT, rate of which changes at runtime, e.g. clocks derived >>>>>> from APLL or bus clocks, which can be reconfigured by cpufreq or devfreq. >>>>>> >>>> >>>> +CC: Sylwester Nawrocki >>>> >>>> Okay. But in cases where there is only 1 valid parent clock provided >>>> through DT (at the moment for Exynos5250/Exynos5420), would it be safe >>>> to set that clock as the parent of CLKOUT? >> >> This is not something to rely on. I have simply omitted remaining CLKOUT >> parents on Exynos 5 SoCs, as I don't have any board with them on which I >> could test this. Eventually they will be added. >> >>>> Otherwise, this clock is >>>> not usable ATM. >> >> On many boards it is already configured properly by the bootloader. >> Although I don't see any reason why you couldn't reparent it in >> (board-specific) sound card driver right now. > > This would require passing the parent's clock specifier in 'clocks' > property of the sound card device node, which I assume is not something > we're generally expected to do in mainline. Although some drivers > happen to be doing it already I think that's a bad example. It sounds > like an abuse of the current clock bindings. Well, an already board-specific driver might have some knowledge of the SoC, so it might not be a huge problem, but I agree that this is not an optimal solution. Best regards, Tomasz -- 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
