Hi Sylwester On 25/07/13 13:34, Sylwester Nawrocki wrote: > On 06/13/2013 06:06 PM, James Hogan wrote: >> Add a CLK_SET_RATE_NO_REPARENT clock flag, which will prevent muxes >> being reparented during clk_set_rate. >> >> To avoid breaking existing platforms, all callers of clk_register_mux() >> are adjusted to pass the new flag. Platform maintainers are encouraged >> to remove the flag if they wish to allow mux reparenting on set_rate. > [..] >> Changes in v3: >> >> * rename/invert CLK_SET_RATE_REMUX to CLK_SET_RATE_NO_REPARENT and move >> to this new patch. >> * patch 3: add CLK_SET_RATE_NO_REPARENT flag to all callers of >> clk_register_mux. If you don't mind your clocks being reparented in >> response to set_rate please let me know and I'll drop the relevant >> portion of the patch. > > Why is this better to change current behaviour of the clock core > and modify all drivers instead of having, e.g. CLK_SET_RATE_REPARENT > set in drivers of hardware that supports clock re-parenting while > setting clock rate ? See this message from Mike Turquette which first suggested it: http://marc.info/?l=linux-kernel&m=136847508109344&w=2 > Is there intention to just have the automatic clock re-parenting > as a default feature in the common clock API ? Yes, that would be the result (except where explicitly disallowed). Unfortunately where such policy should ideally be defined is still up in the air. It's not a property of the hardware, but then it is arguably a property of the environment the bootloader has configured (like the stuff in the /chosen device tree node). Presuming that the usual reason not to reparent a mux is because other important clocks depend on it, the kernel might know enough to work out whether it's safe (unless of course there are other cores/threads in the SoC using the clock that Linux isn't aware of, which brings us back to it being a bootloader environment thing). > My apologies if this has already been answered, I haven't been > following this thread. No problem :) Cheers James -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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