On 11/12/12 08:38, Hiremath, Vaibhav wrote: > On Sun, Nov 11, 2012 at 17:05:07, Igor Grinberg wrote: >> >> >> On 11/08/12 20:34, Jon Hunter wrote: >>> >>> On 11/08/2012 12:17 PM, Paul Walmsley wrote: >>>> On Thu, 8 Nov 2012, Jon Hunter wrote: >>>> >>>>> On 11/08/2012 11:58 AM, Paul Walmsley wrote: >>>>>> On Thu, 8 Nov 2012, Jon Hunter wrote: >>>>>> >>>>>>> Igor was mentioning a h/w scenario where the 32kHz source is not >>>>>>> present. However, I am not sure which devices support this and is >>>>>>> applicable too. >>>>>> >>>>>> Pretty sure Igor is referring to the AM3517/3505. This is very poorly >>>>>> documented, but can be observed in the AM3517 TRM Rev B (SPRUGR0B) Figure >>>>>> 4-23 "PRM Clock Generator" and the AM3517 DM Rev C (SPRS550C) Section 4 >>>>>> "Clock Specifications". >>>>> >>>>> But AFAICT, even in that h/w configuration the internal 32k >>>>> oscillator will be used >>>> >>>> Just to clarify, there's no internal 32k oscillator used on the 3517/3505; >>>> just a divider from the HF clock. >>> >>> Ah yes I see that now! >>> >>>>> and so the gptimer will still have a 32k clock source. >>>> >>>> That's a good question and you might want to check with Igor on that one, >>>> the AM3517 TRM conflicts with the DM as to whether it's available to the >>>> GPTIMER or not :-( >>> >>> Well the external 32k and internal divided down version go through the >>> same mux and so that seems to imply either they are both available to >>> the gptimer or neither is. >> >> Yep, but the /800 do not get you the 32768... >> and that makes the timer suck. >> Of course this can be dealt with in the clock subsystem >> (I remember Paul said that he will look into that), but it will take time. >> >> Also, what about having the sys_clk instead of 32k for higher precision? >> Is that possible already (without my patch)? >> > > Yes, it is possible. You can choose it through bootargs. Is the kernel command line the only way for doing this? I personally dislike it, because it brings multiple maintenance problems. This must be possible at least through DT. -- Regards, Igor. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
