| Message ID | 20200416080245.3203-1-u.kleine-koenig@pengutronix.de (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | aef1a3799b5cb3ba4841f6034497b179646ccc70 |
| Headers | show |
| Series | pwm: imx27: Fix rounding behavior | expand |
On Thu, Apr 16, 2020 at 10:02:45AM +0200, Uwe Kleine-König wrote: > To not trigger the warnings provided by CONFIG_PWM_DEBUG > > - use up-rounding in .get_state() > - don't divide by the result of a division > - don't use the rounded counter value for the period length to calculate > the counter value for the duty cycle > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > drivers/pwm/pwm-imx27.c | 20 ++++++++++---------- > 1 file changed, 10 insertions(+), 10 deletions(-) Applied, thanks. Thierry
On Tue, Jun 02, 2020 at 02:48:35PM +0200, Thierry Reding wrote: > On Thu, Apr 16, 2020 at 10:02:45AM +0200, Uwe Kleine-König wrote: > > To not trigger the warnings provided by CONFIG_PWM_DEBUG > > > > - use up-rounding in .get_state() > > - don't divide by the result of a division > > - don't use the rounded counter value for the period length to calculate > > the counter value for the duty cycle > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > --- > > drivers/pwm/pwm-imx27.c | 20 ++++++++++---------- > > 1 file changed, 10 insertions(+), 10 deletions(-) > > Applied, thanks. > > Thierry Hi Thierry, Just FYI, This change conflicts with one of my patches [1] in the "Convert PWM period and duty cycle to u64" series. [1]: https://patchwork.ozlabs.org/project/linux-pwm/patch/848494725fd1240ed877d0a1471dd11ccea01ff5.1590514331.git.gurus@codeaurora.org/
On Tue, Jun 02, 2020 at 01:42:12PM -0700, Guru Das Srinagesh wrote: > On Tue, Jun 02, 2020 at 02:48:35PM +0200, Thierry Reding wrote: > > On Thu, Apr 16, 2020 at 10:02:45AM +0200, Uwe Kleine-König wrote: > > > To not trigger the warnings provided by CONFIG_PWM_DEBUG > > > > > > - use up-rounding in .get_state() > > > - don't divide by the result of a division > > > - don't use the rounded counter value for the period length to calculate > > > the counter value for the duty cycle > > > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > > --- > > > drivers/pwm/pwm-imx27.c | 20 ++++++++++---------- > > > 1 file changed, 10 insertions(+), 10 deletions(-) > > > > Applied, thanks. > > > > Thierry > > Hi Thierry, > > Just FYI, This change conflicts with one of my patches [1] in the "Convert > PWM period and duty cycle to u64" series. > > [1]: https://patchwork.ozlabs.org/project/linux-pwm/patch/848494725fd1240ed877d0a1471dd11ccea01ff5.1590514331.git.gurus@codeaurora.org/ Uploaded v16 that resolves this issue. Thank you. Guru Das.
diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c index a6e40d4c485f..732a6f3701e8 100644 --- a/drivers/pwm/pwm-imx27.c +++ b/drivers/pwm/pwm-imx27.c @@ -150,13 +150,12 @@ static void pwm_imx27_get_state(struct pwm_chip *chip, prescaler = MX3_PWMCR_PRESCALER_GET(val); pwm_clk = clk_get_rate(imx->clk_per); - pwm_clk = DIV_ROUND_CLOSEST_ULL(pwm_clk, prescaler); val = readl(imx->mmio_base + MX3_PWMPR); period = val >= MX3_PWMPR_MAX ? MX3_PWMPR_MAX : val; /* PWMOUT (Hz) = PWMCLK / (PWMPR + 2) */ - tmp = NSEC_PER_SEC * (u64)(period + 2); - state->period = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk); + tmp = NSEC_PER_SEC * (u64)(period + 2) * prescaler; + state->period = DIV_ROUND_UP_ULL(tmp, pwm_clk); /* * PWMSAR can be read only if PWM is enabled. If the PWM is disabled, @@ -167,8 +166,8 @@ static void pwm_imx27_get_state(struct pwm_chip *chip, else val = imx->duty_cycle; - tmp = NSEC_PER_SEC * (u64)(val); - state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk); + tmp = NSEC_PER_SEC * (u64)(val) * prescaler; + state->duty_cycle = DIV_ROUND_UP_ULL(tmp, pwm_clk); pwm_imx27_clk_disable_unprepare(imx); } @@ -220,22 +219,23 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip); struct pwm_state cstate; unsigned long long c; + unsigned long long clkrate; int ret; u32 cr; pwm_get_state(pwm, &cstate); - c = clk_get_rate(imx->clk_per); - c *= state->period; + clkrate = clk_get_rate(imx->clk_per); + c = clkrate * state->period; - do_div(c, 1000000000); + do_div(c, NSEC_PER_SEC); period_cycles = c; prescale = period_cycles / 0x10000 + 1; period_cycles /= prescale; - c = (unsigned long long)period_cycles * state->duty_cycle; - do_div(c, state->period); + c = clkrate * state->duty_cycle; + do_div(c, NSEC_PER_SEC * prescale); duty_cycles = c; /*
To not trigger the warnings provided by CONFIG_PWM_DEBUG - use up-rounding in .get_state() - don't divide by the result of a division - don't use the rounded counter value for the period length to calculate the counter value for the duty cycle Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- drivers/pwm/pwm-imx27.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)