Hi Uwe, On Sat, Apr 17, 2021 at 05:50:09PM +0200, Uwe Kleine-König wrote: > 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. > I understood, thanks. > > However, I think this means that the device is working as this driver. > > I don't understand this sentence. The description of the struct pwm_state says "PWM enabled status". I thought 'state-> enabled' would hold the working state of the hardware. > > Best regards > Uwe Best regards, Nobuhiro
