On Fri 15 Apr 11:59 PDT 2016, Stephen Boyd wrote: [..]
> ----8<----- > From: Stephen Boyd <[email protected]> > Subject: [PATCH] Input: pmic8xxx-pwrkey: Fix algorithm for converting trigger > delay > > The trigger delay algorithm that converts from microseconds to > the register value looks incorrect. According to most of the PMIC > documentation, the equation is > > delay (Seconds) = (1 / 1024) * 2 ^ (x + 4) > > except for one case where the documentation looks to have a > formatting issue and the equation looks like > > delay (Seconds) = (1 / 1024) * 2 x + 4 > > Most likely this driver was written with the improper > documentation to begin with. According to the downstream sources > the valid delays are from 2 seconds to 1/64 second, and the > latter equation just doesn't make sense for that. Let's fix the > algorithm and the range check to match the documentation and the > downstream sources. > > Reported-by: Bjorn Andersson <[email protected]> Acked-by: Bjorn Andersson <[email protected]> > Cc: John Stultz <[email protected]> > Fixes: 92d57a73e410 ("input: Add support for Qualcomm PMIC8XXX power key") > Signed-off-by: Stephen Boyd <[email protected]> > --- > drivers/input/misc/pmic8xxx-pwrkey.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/input/misc/pmic8xxx-pwrkey.c > b/drivers/input/misc/pmic8xxx-pwrkey.c > index 3f02e0e03d12..67aab86048ad 100644 > --- a/drivers/input/misc/pmic8xxx-pwrkey.c > +++ b/drivers/input/misc/pmic8xxx-pwrkey.c > @@ -353,7 +353,8 @@ static int pmic8xxx_pwrkey_probe(struct platform_device > *pdev) > if (of_property_read_u32(pdev->dev.of_node, "debounce", &kpd_delay)) > kpd_delay = 15625; > > - if (kpd_delay > 62500 || kpd_delay == 0) { > + /* Valid range of pwr key trigger delay is 1/64 sec to 2 seconds. */ > + if (kpd_delay > USEC_PER_SEC * 2 || kpd_delay < USEC_PER_SEC / 64) { > dev_err(&pdev->dev, "invalid power key trigger delay\n"); > return -EINVAL; > } > @@ -385,8 +386,8 @@ static int pmic8xxx_pwrkey_probe(struct platform_device > *pdev) > pwr->name = "pmic8xxx_pwrkey"; > pwr->phys = "pmic8xxx_pwrkey/input0"; > > - delay = (kpd_delay << 10) / USEC_PER_SEC; > - delay = 1 + ilog2(delay); > + delay = (kpd_delay << 6) / USEC_PER_SEC; > + delay = ilog2(delay); Regards, Bjorn
