linux-kernel - Re: [PATCH v3 4/8] iio: adc: Add support for ad4052

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <oqibdd7spdxvlimrwcabqo2xryfplk4q6lnwav5grtl5juud5x@vqfego523x7a>
Date: Tue, 17 Jun 2025 17:34:56 +0200
From: Jorge Marques <gastmaier@...il.com>
To: Uwe Kleine-König <ukleinek@...nel.org>
Cc: Jorge Marques <jorge.marques@...log.com>, 
	Jonathan Cameron <jic23@...nel.org>, Lars-Peter Clausen <lars@...afoo.de>, 
	Michael Hennerich <Michael.Hennerich@...log.com>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Jonathan Corbet <corbet@....net>, David Lechner <dlechner@...libre.com>, 
	Nuno Sá <nuno.sa@...log.com>, Andy Shevchenko <andy@...nel.org>, linux-iio@...r.kernel.org, 
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, linux-doc@...r.kernel.org, 
	linux-pwm@...r.kernel.org
Subject: Re: [PATCH v3 4/8] iio: adc: Add support for ad4052

On Tue, Jun 17, 2025 at 04:59:48PM +0200, Uwe Kleine-König wrote:
> On Tue, Jun 10, 2025 at 09:34:37AM +0200, Jorge Marques wrote:
> > +static int ad4052_get_samp_freq(struct iio_dev *indio_dev,
> > +				struct iio_chan_spec const *chan,
> > +				int *val,
> > +				int *val2)
> > +{
> > +	struct ad4052_state *st = iio_priv(indio_dev);
> > +
> > +	*val = DIV_ROUND_UP_ULL(NSEC_PER_SEC, st->pwm_st.period);
> > +	return IIO_VAL_INT;
> 
> st->pwm_st.period is the period that was requested before. If you want
> the real period that is currently emitted, check pwm_get_state_hw().
> 
Hi Uwe,

I believe only ad4695.c uses this method and the reason for that is if
the pwm is disabled we still want to obtain the requested value.

Reverting slightly to v2, the semantic to allow fetching from hw when
enabled, and using the managed state when disabled, would be:

	struct pwm_state pwm_st;
	int ret

	ret = pwm_get_state_hw(st->cnv_pwm, &pwm_st);
	if (ret)
		goto out_release;

	if (!pwm_st.enabled)
		pwm_st = st->pwm_st;

	*val = DIV_ROUND_UP_ULL(NSEC_PER_SEC, pwm_st.period);

Is this ok?

Best regards,
Jorge
> > +}
> 
> Best regards
> Uwe