[PATCH 06/15] spi: spi-offload-trigger-pwm: Use duty offset

Marcelo Schmitt posted 15 patches 1 month ago
There is a newer version of this series
[PATCH 06/15] spi: spi-offload-trigger-pwm: Use duty offset
Posted by Marcelo Schmitt 1 month ago
From: Axel Haslam <ahaslam@baylibre.com>

Pass the duty offset to the waveform pwm.

Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
---
 drivers/spi/spi-offload-trigger-pwm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-offload-trigger-pwm.c b/drivers/spi/spi-offload-trigger-pwm.c
index 805ed41560df..8413aeb3689d 100644
--- a/drivers/spi/spi-offload-trigger-pwm.c
+++ b/drivers/spi/spi-offload-trigger-pwm.c
@@ -51,13 +51,13 @@ static int spi_offload_trigger_pwm_validate(struct spi_offload_trigger *trigger,
 	wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
 	/* REVISIT: 50% duty-cycle for now - may add config parameter later */
 	wf.duty_length_ns = wf.period_length_ns / 2;
-
+	wf.duty_offset_ns = periodic->offset_ns;
 	ret = pwm_round_waveform_might_sleep(st->pwm, &wf);
 	if (ret < 0)
 		return ret;
 
 	periodic->frequency_hz = DIV_ROUND_UP_ULL(NSEC_PER_SEC, wf.period_length_ns);
-
+	periodic->offset_ns = wf.duty_offset_ns;
 	return 0;
 }
 
@@ -77,6 +77,7 @@ static int spi_offload_trigger_pwm_enable(struct spi_offload_trigger *trigger,
 	wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
 	/* REVISIT: 50% duty-cycle for now - may add config parameter later */
 	wf.duty_length_ns = wf.period_length_ns / 2;
+	wf.duty_offset_ns = periodic->offset_ns;
 
 	return pwm_set_waveform_might_sleep(st->pwm, &wf, false);
 }
-- 
2.39.2
Re: [PATCH 06/15] spi: spi-offload-trigger-pwm: Use duty offset
Posted by David Lechner 1 month ago
On 8/29/25 7:42 PM, Marcelo Schmitt wrote:
> From: Axel Haslam <ahaslam@baylibre.com>
> 
> Pass the duty offset to the waveform pwm.
> 
> Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
> ---
>  drivers/spi/spi-offload-trigger-pwm.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/spi-offload-trigger-pwm.c b/drivers/spi/spi-offload-trigger-pwm.c
> index 805ed41560df..8413aeb3689d 100644
> --- a/drivers/spi/spi-offload-trigger-pwm.c
> +++ b/drivers/spi/spi-offload-trigger-pwm.c
> @@ -51,13 +51,13 @@ static int spi_offload_trigger_pwm_validate(struct spi_offload_trigger *trigger,
>  	wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
>  	/* REVISIT: 50% duty-cycle for now - may add config parameter later */
>  	wf.duty_length_ns = wf.period_length_ns / 2;
> -
> +	wf.duty_offset_ns = periodic->offset_ns;

I would be tempted to put the loop check here:

	offload_offset_ns = periodic->offset_ns;

	do {
		wf.offset_ns = offload_offset_ns;
		ret = pwm_round_waveform_might_sleep(st->pwm, &wf);
		if (ret)
			return ret;
		offload_offset_ns += 10;

	} while (wf.offset_ns < periodic->offset_ns);

	wf.duty_offset_ns = periodic->offset_ns;

instead of in the ADC driver so that all future callers don't have to
repeat this.

Also cc: Uwe in case he has any better suggestions on how to avoid
repeating such verbose validations by all uses of the PWM waveform
APIs.


>  	ret = pwm_round_waveform_might_sleep(st->pwm, &wf);
>  	if (ret < 0)
>  		return ret;
>  
>  	periodic->frequency_hz = DIV_ROUND_UP_ULL(NSEC_PER_SEC, wf.period_length_ns);
> -
> +	periodic->offset_ns = wf.duty_offset_ns;
>  	return 0;
>  }
>  
> @@ -77,6 +77,7 @@ static int spi_offload_trigger_pwm_enable(struct spi_offload_trigger *trigger,
>  	wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
>  	/* REVISIT: 50% duty-cycle for now - may add config parameter later */
>  	wf.duty_length_ns = wf.period_length_ns / 2;
> +	wf.duty_offset_ns = periodic->offset_ns;
>  
>  	return pwm_set_waveform_might_sleep(st->pwm, &wf, false);
>  }
Re: [PATCH 06/15] spi: spi-offload-trigger-pwm: Use duty offset
Posted by Andy Shevchenko 1 month ago
On Sat, Aug 30, 2025 at 3:42 AM Marcelo Schmitt
<marcelo.schmitt@analog.com> wrote:
>
> Pass the duty offset to the waveform pwm.

...

>         wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
>         /* REVISIT: 50% duty-cycle for now - may add config parameter later */
>         wf.duty_length_ns = wf.period_length_ns / 2;
> -

Stray - line

> +       wf.duty_offset_ns = periodic->offset_ns;
>         ret = pwm_round_waveform_might_sleep(st->pwm, &wf);
>         if (ret < 0)
>                 return ret;
>
>         periodic->frequency_hz = DIV_ROUND_UP_ULL(NSEC_PER_SEC, wf.period_length_ns);
> -

Ditto.

> +       periodic->offset_ns = wf.duty_offset_ns;
>         return 0;
>  }
>
> @@ -77,6 +77,7 @@ static int spi_offload_trigger_pwm_enable(struct spi_offload_trigger *trigger,
>         wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
>         /* REVISIT: 50% duty-cycle for now - may add config parameter later */
>         wf.duty_length_ns = wf.period_length_ns / 2;
> +       wf.duty_offset_ns = periodic->offset_ns;

>

Especially as it seems that the pattern is to have a blank line before
last return statements.

>         return pwm_set_waveform_might_sleep(st->pwm, &wf, false);
>  }


-- 
With Best Regards,
Andy Shevchenko