Hello,
On Wed, Jun 24, 2020 at 03:39:52PM +0000, Roy Im wrote:
> On Wed, Jun 24, 2020 at 10:37 PM, Uwe Kleine-König wrote:
> > On Wed, Jun 24, 2020 at 12:04:24PM +0900, Roy Im wrote:
> > > period2freq = 1000000 / state.period;
> > > if (period2freq < DA7280_MIN_PWM_FREQ_KHZ ||
> > > period2freq > DA7280_MAX_PWM_FREQ_KHZ) {
> > > dev_err(dev, "Unsupported PWM frequency (%u)\n",
> > > period2freq);
> > > return -EINVAL;
> > > }
> > > If you look ok, let me update this so.
> >
> > looks fine.
> >
> > Note that you don't need the division if you check for:
> >
> > if (state.period > 100000 || state.period < 4000) {
> > ...
> >
> > (maybe the compiler is already clever enough to get rid of the division for you, but then the check is:
> >
> > if (state.period > 100000 || state.period < 3985) {
> >
> > because of rounding errors.)
>
> OK, you are right, that will be better. So let me change that as below
> if you look fine.
I look fine, the code however is wrong. :-)
> /* Check PWM period, PWM freq = 1000000 / state.period.
> * The valid PWM freq range: 10k ~ 250kHz.
> */
> if (state.period > 100000 || state.period < 3985) {
You want 4000 here ---------------------------------^^^^, don't you?
> dev_err(dev, "Unsupported PWM period (%u)\n",
> state.period);
> return -EINVAL;
> }
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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