On Sun, 7 Apr 2019 at 05:13, Nicholas Mc Guire <[email protected]> wrote: > > Providing a range for usleep_range() allows the hrtimer subsystem to > coalesce timers - the delay is runtime configurable so a factor 2 > is taken to provide the range. > > Signed-off-by: Nicholas Mc Guire <[email protected]> > --- > > Problem located with an experimental coccinelle script > > Q: Basically usleep_range() with min == max never makes much sense notably > in non-atomic context. If the factor of 2 is tolerable or a fixed > offset of e.g. 1000 would be more suitable is not clear to me - maybe > someone familiar with that driver can clarify this. > > Patch was compile tested with: u8500_defconfig (implies COMMON_CLK=y) > (with some sparse warnings about not implemented system calls) > > Patch is against 5.1-rc3 (localversion-next is next=20190405) > > drivers/clk/ux500/clk-sysctrl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/clk/ux500/clk-sysctrl.c b/drivers/clk/ux500/clk-sysctrl.c > index 7c0403b..a1fa3fb 100644 > --- a/drivers/clk/ux500/clk-sysctrl.c > +++ b/drivers/clk/ux500/clk-sysctrl.c > @@ -42,7 +42,7 @@ static int clk_sysctrl_prepare(struct clk_hw *hw) > clk->reg_bits[0]); > > if (!ret && clk->enable_delay_us) > - usleep_range(clk->enable_delay_us, clk->enable_delay_us); > + usleep_range(clk->enable_delay_us, clk->enable_delay_us*2);
The range being used is actually in ms, so not sure we actually need to double it for the range. How about adding ~25% instead, along the lines of below: usleep_range(clk->enable_delay_us, clk->enable_delay_us + (clk->enable_delay_us >> 2)); Kind regards Uffe
