Hello Nobuhiro, On Fri, Apr 16, 2021 at 09:15:23PM +0900, Nobuhiro Iwamatsu wrote: > > > > For me the critical (and only) difference between "off" and > > > > "duty cycle = 0" is that when a new configuration is to be applied. In > > > > the "off" state a new period can (and should) start immediately, while > > > > with "duty_cycle = 0" the rising edge should be delayed until the > > > > currently running period is over.[1] > > > > > > > > So the thing to do here (IMHO) is: > > > > > > > > Iff with PIPGM_PCSR = 0 configuring a new setting (that is finalized > > > > with writing a non-zero value to PIPGM_PCSR) completes the currently > > > > running period, then always assume the PWM as enabled. > > > > > > Yes, this device works that way. > > > > OK, then please use > > > > state->enabled = true > > > > unconditionally in visconti_pwm_get_state(). > > Please let me check. > If I unconditionally add 'state->enabled = true' to visconti_pwm_get_state(), > state->enabled is set to true because visconti_pwm_get_state() is called when > the device is created (this is when I write the device number to the export of > /sys/class/pwm/pwmchip0 ). > And since PIPGM_PCSR is 0 in this state, the pulse by PWM is not output. A PWM that is currently configured with .enabled = true and .duty_cycle = 0 doesn't have a pulse, so this is fine. > However, I think this means that the device is working as this driver. I don't understand this sentence. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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