diff options
| author |   Paul Cercueil <paul@crapouillou.net> | 2020-05-27 13:52:23 +0200 |
|---|---|---|
| committer |   Thierry Reding <thierry.reding@gmail.com> | 2020-06-02 14:24:00 +0200 |
| commit | 9017dc4fbd59c09463019ce494cfe36d654495a8 (patch) | |
| tree | 284a1b3f595e017977c4c0e9fd3836947e42b521 /drivers/pwm/pwm-jz4740.c | |
| parent | pwm: jz4740: Drop dependency on MACH_INGENIC (diff) | |
| download | linux-dev-9017dc4fbd59c09463019ce494cfe36d654495a8.tar.xz linux-dev-9017dc4fbd59c09463019ce494cfe36d654495a8.zip | |
pwm: jz4740: Enhance precision in calculation of duty cycle
Calculating the hardware value for the duty from the hardware value of
the period resulted in a precision loss versus calculating it from the
clock rate directly.
(Also remove a cast that doesn't really need to be here)
Fixes: f6b8a5700057 ("pwm: Add Ingenic JZ4740 support")
Cc: <stable@vger.kernel.org>
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm/pwm-jz4740.c')
| -rw-r--r-- | drivers/pwm/pwm-jz4740.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c index 3cd5c054ad9a..4fe9d99ac9a9 100644 --- a/drivers/pwm/pwm-jz4740.c +++ b/drivers/pwm/pwm-jz4740.c @@ -158,11 +158,11 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, /* Calculate period value */ tmp = (unsigned long long)rate * state->period; do_div(tmp, NSEC_PER_SEC); - period = (unsigned long)tmp; + period = tmp; /* Calculate duty value */ - tmp = (unsigned long long)period * state->duty_cycle; - do_div(tmp, state->period); + tmp = (unsigned long long)rate * state->duty_cycle; + do_div(tmp, NSEC_PER_SEC); duty = period - tmp; if (duty >= period) |