| Message ID | 1520594661-6897-1-git-send-email-yoshihiro.shimoda.uh@renesas.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | pwm: rcar: fix a condition to prevent mismatch value setting to duty | expand |
On Fri, Mar 09, 2018 at 08:24:21PM +0900, Yoshihiro Shimoda wrote: > From: Ryo Kodama <ryo.kodama.vz@renesas.com> > > This patch fixes an issue that is possible to set mismatch value > to duty for R-Car PWM if we input the following commands: > > # cd /sys/class/pwm/<pwmchip>/ > # echo 0 > export > # cd pwm0 > # echo 30 > period > # echo 30 > duty_cycle > # echo 0 > duty_cycle > # cat duty_cycle > 0 > # echo 1 > enable > --> Then, the actual duty_cycle is 30, not 0. > > So, this patch adds a condition into rcar_pwm_config() to fix > this issue. > > Signed-off-by: Ryo Kodama <ryo.kodama.vz@renesas.com> > [shimoda: revise the commit log and add Fixes and Cc tags] > Fixes: ed6c1476bf7f ("pwm: Add support for R-Car PWM Timer") > Cc: Cc: <stable@vger.kernel.org> # v4.4+ > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> > --- > drivers/pwm/pwm-rcar.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) Applied, thanks. Thierry
diff --git a/drivers/pwm/pwm-rcar.c b/drivers/pwm/pwm-rcar.c index 1c85ecc..0fcf94f 100644 --- a/drivers/pwm/pwm-rcar.c +++ b/drivers/pwm/pwm-rcar.c @@ -156,8 +156,12 @@ static int rcar_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, if (div < 0) return div; - /* Let the core driver set pwm->period if disabled and duty_ns == 0 */ - if (!pwm_is_enabled(pwm) && !duty_ns) + /* + * Let the core driver set pwm->period if disabled and duty_ns == 0. + * But, this driver should prevent to set the new duty_ns if current + * duty_cycle is not set + */ + if (!pwm_is_enabled(pwm) && !duty_ns && !pwm->state.duty_cycle) return 0; rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);