Messages in this thread | | | Date | Fri, 16 Jul 2021 09:09:43 +0200 | From | Uwe Kleine-König <> | Subject | Re: [v9 2/2] pwm: Add Aspeed ast2600 PWM support |
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Hello Billy,
On Fri, Jul 16, 2021 at 01:48:20AM +0000, Billy Tsai wrote: > On 2021/7/15, 11:06 PM, "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>> wrote: > > Another is: The PWM doesn't support duty_cycle 0, on such a request the > > PWM is disabled which results in a constant inactive level. > > > (This is correct, is it? Or does it yield a constant 0 level?) > > Our pwm can support duty_cycle 0 by unset CLK_ENABLE.
This has a slightly different semantic though. Some consumer might expect that the following sequence:
pwm_apply(mypwm, { .period = 10000, .duty_cycle = 10000, .enabled = true }) pwm_apply(mypwm, { .period = 10000, .duty_cycle = 0, .enabled = true }) pwm_apply(mypwm, { .period = 10000, .duty_cycle = 10000, .enabled = true })
results in the output being low for an integer multiple of 10 µs. This isn't given with setting CLK_ENABLE to zero, is it? (I didn't recheck, if the PWM doesn't complete periods on reconfiguration this doesn't matter much though.)
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ | [unhandled content-type:application/pgp-signature] | |