On Fri, May 01, 2015 at 12:21:20AM +0200, Sebastian Hesselbarth wrote: > On 30.04.2015 23:20, Michael Welling wrote: > >On Thu, Apr 30, 2015 at 10:44:07PM +0200, Sebastian Hesselbarth wrote: > [...] > >>What I noticed about your clk2 that you always measure as 0 Hz is > >>that none of your clocks is prepared/enabled. > >> > >>Currently, the si5351 driver only ensures the output is enabled > >>when si5351_clkout_prepare() is called. > >> > >>As long as you do not have a clk consumer that properly prepare/enables > >>the clock output, it may remain disabled. > >> > >>We should probably have additional DT properties and corresponding > >>pdata to force clkoutN always on. > > > >Does the silabs,disable-state of 3 (SI5351_DISABLE_NEVER) take care > >of this? > > That would be the HW version of never disabling the clock output. > I never really tried the property, does it work as expected? This did not appear to effect the behavior. > > >Otherwise is there a simple registration that will do this? > > The SW version of such a property would involve CLK_IGNORE_UNUSED > and enabling all requested clock outputs on probe(). > > If above HW property already works, I think it should be enough. > > [...] > >>>It should be noted that if I program the device's register map in the > >>>bootloader the device keeps the correct frequency outputs. > >> > >>"keeps"? You mean "generates", don't you? > >> > > > >Yes the clocks are generated and do not get effected by the driver. > > IIRC, clk API does check if requested rate and current rate match > already. If they do, it does not request the same rate again. > So I found that the audio codec that I am driving with clk2 could register the clock and allowed the clock to be enabled and disabled by playing audio. This is when I noticed some strange behavior. The first time I attempt to play audio the clock does not turn on blocking the audio from playing. After I interrupt and the clock is disabled for the first time, the successive clock enables work as expected. Something tells me that a fault off some kind is occurring on initial configuration. > Sebastian > -- 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
