On Thu, Sep 19, 2019 at 01:58:35PM +0200, Sylwester Nawrocki wrote:
On 9/18/19 16:31, Charles Keepax wrote:
@@ -2315,6 +2396,8 @@ static int _wm8994_set_fll(struct snd_soc_component *component, int id, int src,
active_dereference(component); }
if (mclk)clk_disable_unprepare(mclk);I don't think this works in the case of changing active FLLs. The driver looks like it allows changing the FLL configuration whilst the FLL is already active in which case it you would have two wm8994_set_fll calls enabling the FLL but only a single one disabling it. Resulting in the FLL being off but the MCLK being left enabled.
Indeed I missed this scenario, or rather assumed it won't be used. But since the driver allows reconfiguring active FLLs we should make sure such use case remains properly supported.
What I came up so far as a fix is reading current FLL refclk source and if FLL was enabled with that source disabling refclk, before we change FLL configuration to new one. So we have clk_disable_unprepare(MCLK) more closely following FLL enable bit changes. I have tested it and it seems to work - something like below. Do you think it makes sense?
Yeah I think that looks good, it is very similar to what we did on Arizona and I haven't found any problems with that yet :-)
Thanks, Charles