From: Paul Cercueil Date: Wed, 27 May 2020 11:52:23 +0000 (+0200) Subject: pwm: jz4740: Enhance precision in calculation of duty cycle X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9017dc4fbd59c09463019ce494cfe36d654495a8;p=linux.git 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: Suggested-by: Uwe Kleine-König Reviewed-by: Uwe Kleine-König Signed-off-by: Paul Cercueil Signed-off-by: Thierry Reding --- diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c index 3cd5c054ad9af..4fe9d99ac9a90 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)