On Wed, Apr 08, 2015 at 09:32:05PM +0530, Anand Moon wrote: > Hi Guenter, > > Initially the board bootup the cooling level state is 0. > So update the duty cycle and this power off the fan. > As their is no state change the fan will not spin. > > Once the temperature sensor is reached to alert temperature it changes state. > With the state change the fan cools the CPU and then stop's > > I have observed this state change with tmon utility in linux/tools/thermal/tmon/ > Sorry, I am missing something. I still don't see what problem you are fixing with this patch. What behavior is wrong with the current code, and how does your patch fix it ? Guenter > -Anand Moon > > On 8 April 2015 at 21:02, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > On Wed, Apr 08, 2015 at 10:44:15AM +0200, Lukasz Majewski wrote: > >> Hi Anand, > >> > >> > Below changes depend on following patch. > >> > https://patchwork.kernel.org/patch/5944061/ > >> > > >> > Update the pwm_config with duty then update the pwm_disable > >> > to poweroff the cpu fan. > >> > > > > > Unfortunately, the patch does not include an explanation why it is needed. > > > > The original code presumably did not update the duty cycle because > > pwm was about to be disabled anyway. That kind of made sense to me. > > Updating the duty cycle to 0 just to disable the pwm channel right > > afterwards does not immediately make sense. > > > > Given that, I would expect to see a rationale here. Why is this patch needed ? > > Does it fix a bug ? If yes, pelase describe the bug. If not, what is the > > purpose of this patch ? > > > > Maybe that is all explained in patch 0/6, which I was not copied on. Even > > if so, the reationale will be needed in the changelog to explain to future > > developers why this change was made. > > > > Thanks, > > Guenter > > > >> > Tested on OdroidXU3 board. > >> > > >> > Signed-off-by: Anand Moon <linux.amoon@xxxxxxxxx> > >> > --- > >> > drivers/hwmon/pwm-fan.c | 10 ++++------ > >> > 1 file changed, 4 insertions(+), 6 deletions(-) > >> > > >> > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > >> > index 7c83dc4..f25c841 100644 > >> > --- a/drivers/hwmon/pwm-fan.c > >> > +++ b/drivers/hwmon/pwm-fan.c > >> > @@ -44,26 +44,24 @@ static int __set_pwm(struct pwm_fan_ctx *ctx, > >> > unsigned long pwm) int ret = 0; > >> > > >> > mutex_lock(&ctx->lock); > >> > + > > > > [ please refrain from unnecessary whitespace changes ] > > > >> > if (ctx->pwm_value == pwm) > >> > goto exit_set_pwm_err; > >> > > >> > - if (pwm == 0) { > >> > - pwm_disable(ctx->pwm); > >> > - goto exit_set_pwm; > >> > - } > >> > - > >> > duty = DIV_ROUND_UP(pwm * (ctx->pwm->period - 1), MAX_PWM); > >> > ret = pwm_config(ctx->pwm, duty, ctx->pwm->period); > >> > if (ret) > >> > goto exit_set_pwm_err; > >> > > >> > + if (pwm == 0) > >> > + pwm_disable(ctx->pwm); > >> > + > >> > if (ctx->pwm_value == 0) { > >> > ret = pwm_enable(ctx->pwm); > >> > if (ret) > >> > goto exit_set_pwm_err; > >> > } > >> > > >> > -exit_set_pwm: > >> > ctx->pwm_value = pwm; > >> > exit_set_pwm_err: > >> > mutex_unlock(&ctx->lock); > >> > >> Reviewed-by: Lukasz Majewski <l.majewski@xxxxxxxxxxx> > >> > >> BTW: I've added Guenter to CC. > >> > >> -- > >> Best regards, > >> > >> Lukasz Majewski > >> > >> Samsung R&D Institute Poland (SRPOL) | Linux Platform Group -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
