On Thu, Mar 05, 2015 at 07:53:16AM +0000, Zha, Qipeng wrote: > Hi > > I got pwm subsystem git tree info as below from v3.19-rc6 MAINTAINER > And I clone it, found the version is v3.12 Is the tree current > maintain tree ? or there is a new one, thanks. > > git git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm.git
You're probably looking at the master branch, but I don't update that. Use the for-next branch, which is what gets merged into linux-next. Thierry > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Shawn Guo > Sent: Monday, March 02, 2015 8:32 PM > To: Gaetan Hug > Cc: [email protected]; [email protected]; > [email protected]; [email protected] > Subject: Re: [PATCH] pwm: mxs: fix period divider computation > > On Wed, Feb 18, 2015 at 02:06:34PM +0100, Gaetan Hug wrote: > > The driver computes which clock divider it sould be using from the > > requested period. This computation assumes that the link between the > > register value and the actual divider value is raising 2 to the power > > of the registry value. > > > > div = 1 << regvalue > > > > This is true only for the first 5 values out of 8. Next values are 64, > > 256 and, 1024 - instead of 32, 64, 128. > > Just checked i.MX28 Reference Manual, and yes, this is the case. > > > This affects only the users requesting a period > 0.04369s. > > > > Replace the computation with a look-up table. > > Your SoB is missing here. Otherwise, > > Acked-by: Shawn Guo <[email protected]> > > > --- > > drivers/pwm/pwm-mxs.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c index > > f75ecb0..c65e183 100644 > > --- a/drivers/pwm/pwm-mxs.c > > +++ b/drivers/pwm/pwm-mxs.c > > @@ -35,6 +35,8 @@ > > #define PERIOD_CDIV(div) (((div) & 0x7) << 20) > > #define PERIOD_CDIV_MAX 8 > > > > +static unsigned const int cdiv[PERIOD_CDIV_MAX] = {1, 2, 4, 8, 16, > > +64, 256, 1024}; > > + > > struct mxs_pwm_chip { > > struct pwm_chip chip; > > struct clk *clk; > > @@ -54,13 +56,13 @@ static int mxs_pwm_config(struct pwm_chip *chip, > > struct pwm_device *pwm, > > > > rate = clk_get_rate(mxs->clk); > > while (1) { > > - c = rate / (1 << div); > > + c = rate / cdiv[div]; > > c = c * period_ns; > > do_div(c, 1000000000); > > if (c < PERIOD_PERIOD_MAX) > > break; > > div++; > > - if (div > PERIOD_CDIV_MAX) > > + if (div >= PERIOD_CDIV_MAX) > > return -EINVAL; > > } > > > > -- > > 1.7.10.4 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the > body of a message to [email protected] More majordomo info at > http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the > body of a message to [email protected] More majordomo info at > http://vger.kernel.org/majordomo-info.html
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