pwm: visconti: Fix and simplify period calculation
With the original code a request for period = 65536000 ns and period =
32768000 ns yields the same register settings (which results in 32768000
ns) because the value for pwmc0 was miscalculated.
Also simplify using that fls(0) is 0.
Fixes: 721b595744
("pwm: visconti: Add Toshiba Visconti SoC PWM support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
parent
e9fdf122cf
commit
937efa29e7
@ -82,17 +82,14 @@ static int visconti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
|
||||
return -ERANGE;
|
||||
|
||||
/*
|
||||
* PWMC controls a divider that divides the input clk by a
|
||||
* power of two between 1 and 8. As a smaller divider yields
|
||||
* higher precision, pick the smallest possible one.
|
||||
* PWMC controls a divider that divides the input clk by a power of two
|
||||
* between 1 and 8. As a smaller divider yields higher precision, pick
|
||||
* the smallest possible one. As period is at most 0xffff << 3, pwmc0 is
|
||||
* in the intended range [0..3].
|
||||
*/
|
||||
if (period > 0xffff) {
|
||||
pwmc0 = ilog2(period >> 16);
|
||||
if (WARN_ON(pwmc0 > 3))
|
||||
return -EINVAL;
|
||||
} else {
|
||||
pwmc0 = 0;
|
||||
}
|
||||
pwmc0 = fls(period >> 16);
|
||||
if (WARN_ON(pwmc0 > 3))
|
||||
return -EINVAL;
|
||||
|
||||
period >>= pwmc0;
|
||||
duty_cycle >>= pwmc0;
|
||||
|
Loading…
Reference in New Issue
Block a user