Hello Biju, On Sat, Sep 24, 2022 at 10:53:30AM +0000, Biju Das wrote: > > Subject: RE: [PATCH v6 2/2] pwm: Add support for RZ/G2L GPT > > > > Thanks for the feedback. > > > > > Subject: Re: [PATCH v6 2/2] pwm: Add support for RZ/G2L GPT > > > > > > Hello, > > > > > > On Wed, Sep 21, 2022 at 01:46:54PM +0000, Biju Das wrote: > > > > > Actually it's worse: > > > > > > > > > > - When both channels are used, setting the duty-cycle on one > > > aborts the > > > > > currently running period on the other and starts it anew. > > > > > > > > > > (Did I get this correctly?) > > > > > > > > I think, I have fixed that issue with the below logic Which allows > > > to > > > > update duty cycle on the fly. > > > > > > > > Now the only limitation is w.r.to disabling channels as we need to > > > > disable together as stopping the counter affects both. > > > > > > > > /* > > > > * Counter must be stopped before modifying mode, prescaler, > > > timer > > > > * counter and buffer enable registers. These registers are > > > shared > > > > * between both channels. So allow updating these registers only > > > for the > > > > * first enabled channel. > > > > */ > > > > if (rzg2l_gpt->user_count <= 1) > > > > rzg2l_gpt_disable(rzg2l_gpt); > > > > > > > > is_counter_running = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTCR) & > > > RZG2L_GTCR_CST; > > > > if (!is_counter_running) > > > > /* GPT set operating mode (saw-wave up-counting) */ > > > > rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR, RZG2L_GTCR_MD, > > > > RZG2L_GTCR_MD_SAW_WAVE_PWM_MODE); > > > > > > So if the PWM is already running (e.g. from the bootloader) and the > > > mode is wrong, this isn't fixed? Similar problems in the if blocks > > > below. > > What is your thought on caching the registers that needs counter to be stopped > for updating values. Basically, we don't stop the counter if the values are same? I don't see a very relevant difference between caching and reading the registers. Whatever is fine for you. > This allows updating period/duty cycle on the fly without stopping the counter > even for the single channel use case. I didn't get the relevant difference, but the result sounds good. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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