Quoting Uwe (2019-09-24 05:21:47) > On Fri, Sep 20, 2019 at 05:39:06PM +0200, Alexandre Belloni wrote: > > Note that this was already discussed a while ago and Arnd said this > > approach was > > reasonable: > > https://lore.kernel.org/lkml/6120818.MyeJZ74hYa@wuerfel/ > > > > drivers/clk/at91/clk-main.c | 5 ++++- > > drivers/clk/at91/sckc.c | 20 ++++++++++++++++---- > > 2 files changed, 20 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c > > index f607ee702c83..ccd48e7a3d74 100644 > > --- a/drivers/clk/at91/clk-main.c > > +++ b/drivers/clk/at91/clk-main.c > > @@ -293,7 +293,10 @@ static int clk_main_probe_frequency(struct regmap > > *regmap) > > regmap_read(regmap, AT91_CKGR_MCFR, &mcfr); > > if (mcfr & AT91_PMC_MAINRDY) > > return 0; > > - usleep_range(MAINF_LOOP_MIN_WAIT, MAINF_LOOP_MAX_WAIT); > > + if (system_state < SYSTEM_RUNNING) > > + udelay(MAINF_LOOP_MIN_WAIT); > > + else > > + usleep_range(MAINF_LOOP_MIN_WAIT, > > MAINF_LOOP_MAX_WAIT); > > Given that this construct is introduced several times, I wonder if we > want something like: > > static inline void early_usleep_range(unsigned long min, unsigned > long max) > { > if (system_state < SYSTEM_RUNNING) > udelay(min); > else > usleep_range(min, max); > } >
Maybe, but I think the intent is to not encourage this behavior? So providing a wrapper will make it "easy" and then we'll have to tell users to stop calling it. Another idea would be to make usleep_range() "do the right thing" and call udelay if the system isn't running. And another idea from tlgx[1] is to pull the delay logic into another clk op that we can call to see when the enable or prepare is done. That may be possible by introducing another clk_ops callback that when present indicates we should sleep or delay for so much time while waiting for the prepare or enable to complete. [1] https://lkml.kernel.org/r/alpine.DEB.2.11.1606061448010.28031@nanos
