From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Paul Cercueil <paul@crapouillou.net>
Cc: Thierry Reding <thierry.reding@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org,
linux-mips@vger.kernel.org, linux-doc@vger.kernel.org,
linux-clk@vger.kernel.org
Subject: Re: [PATCH v9 12/27] pwm: jz4740: Use regmap from TCU driver
Date: Sat, 5 Jan 2019 22:18:20 +0100 [thread overview]
Message-ID: <20190105211820.lax3opgdhyn662tw@pengutronix.de> (raw)
In-Reply-To: <1546721178.28727.0@crapouillou.net>
Hello Paul,
On Sat, Jan 05, 2019 at 05:46:18PM -0300, Paul Cercueil wrote:
> On Sat, Jan 5, 2019 at 4:42 PM, Uwe Kleine-König
> <u.kleine-koenig@pengutronix.de> wrote:
> > On Thu, Dec 27, 2018 at 07:13:04PM +0100, Paul Cercueil wrote:
> > > The ingenic-timer "TCU" driver provides us with a regmap, that we
> > > can
> > > use to safely access the TCU registers.
> > >
> > > While this driver is devicetree-compatible, it is never (as of now)
> > > probed from devicetree, so this change does not introduce a ABI
> > > problem
> > > with current devicetree files.
> >
> > Does it change behaviour? If so, how?
>
> No, it does not change the behaviour.
Then this paragraph in the commit log can better be dropped.
> > > @@ -113,26 +117,37 @@ static int jz4740_pwm_apply(struct pwm_chip
> > > *chip, struct pwm_device *pwm,
> > >
> > > jz4740_pwm_disable(chip, pwm);
> > >
> > > - jz4740_timer_set_count(pwm->hwpwm, 0);
> > > - jz4740_timer_set_duty(pwm->hwpwm, duty);
> > > - jz4740_timer_set_period(pwm->hwpwm, period);
> > > + /* Set abrupt shutdown */
> > > + regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
> > > + TCU_TCSR_PWM_SD, TCU_TCSR_PWM_SD);
> >
> > I think I already pointed that out before: abrupt mode is wrong. If
> > .apply is called with a new set of parameters the currently running
> > period with the old values is expected to complete before the new values
> > take effect.
>
> You pointed it, indeed; but I won't change it until I can verify that the
> behaviour is correct (which does not seem to be the case even if I leave
> this bit cleared). Besides, this is the TCU patchset, fixes and patches
> unrelated to the TCU don't belong here.
So abrupt mode was already used before? Then maybe note in a comment
that this is wrong but kept for now as this change is only refactoring
without changing behaviour.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2019-01-05 21:18 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-27 18:12 [PATCH v9 00/27] Ingenic TCU patchset v9 Paul Cercueil
2018-12-27 18:12 ` [PATCH v9 01/27] dt-bindings: ingenic: Add DT bindings for TCU clocks Paul Cercueil
2018-12-27 18:12 ` [PATCH v9 02/27] doc: Add doc for the Ingenic TCU hardware Paul Cercueil
2018-12-27 18:12 ` [PATCH v9 03/27] dt-bindings: Add doc for the Ingenic TCU drivers Paul Cercueil
2018-12-28 21:48 ` Rob Herring
2018-12-27 18:12 ` [PATCH v9 04/27] clocksource: Add a new timer-ingenic driver Paul Cercueil
2019-02-25 15:55 ` Daniel Lezcano
2019-02-25 22:59 ` Paul Cercueil
2018-12-27 18:12 ` [PATCH v9 05/27] clocksource: Add driver for the Ingenic JZ47xx OST Paul Cercueil
2018-12-27 18:12 ` [PATCH v9 06/27] MAINTAINERS: Add myself as maintainer for Ingenic TCU drivers Paul Cercueil
2018-12-27 18:12 ` [PATCH v9 07/27] watchdog: jz4740: Use WDT clock provided by TCU driver Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 08/27] watchdog: jz4740: Use regmap " Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 09/27] watchdog: jz4740: Avoid starting watchdog in set_timeout Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 10/27] watchdog: jz4740: Drop dependency on MACH_JZ47xx, use COMPILE_TEST Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 11/27] pwm: jz4740: Apply configuration atomically Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 12/27] pwm: jz4740: Use regmap from TCU driver Paul Cercueil
2019-01-05 19:42 ` Uwe Kleine-König
2019-01-05 20:46 ` Paul Cercueil
2019-01-05 21:18 ` Uwe Kleine-König [this message]
2018-12-27 18:13 ` [PATCH v9 13/27] pwm: jz4740: Use clocks " Paul Cercueil
2019-01-05 19:45 ` Uwe Kleine-König
2019-01-05 20:52 ` Paul Cercueil
2019-01-05 21:19 ` Uwe Kleine-König
2018-12-27 18:13 ` [PATCH v9 14/27] pwm: jz4740: Improve algorithm of clock calculation Paul Cercueil
2019-01-05 19:57 ` Uwe Kleine-König
2019-01-05 21:05 ` Paul Cercueil
2019-01-05 21:27 ` Uwe Kleine-König
2019-01-10 14:04 ` Paul Cercueil
2019-02-23 1:17 ` Paul Cercueil
2019-02-28 18:42 ` Stephen Boyd
2018-12-27 18:13 ` [PATCH v9 15/27] pwm: jz4740: Allow selection of PWM channels 0 and 1 Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 16/27] pwm: jz4740: Drop dependency on MACH_INGENIC, use COMPILE_TEST Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 17/27] pwm: jz4740: Remove unused devicetree compatible strings Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 18/27] clk: jz4740: Add TCU clock Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 19/27] MIPS: Kconfig: Select TCU timer driver when MACH_INGENIC is set Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 20/27] MIPS: jz4740: Add DTS nodes for the TCU drivers Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 21/27] MIPS: qi_lb60: Move PWM devices to devicetree Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 22/27] MIPS: qi_lb60: Reduce system timer and clocksource to 750 kHz Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 23/27] MIPS: CI20: Reduce system timer to 3 MHz Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 24/27] MIPS: CI20: defconfig: enable OST driver Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 25/27] MIPS: GCW0: Reduce system timer to 750 kHz Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 26/27] MIPS: GCW0: defconfig: Enable OST, watchdog, PWM drivers Paul Cercueil
2018-12-27 18:13 ` [PATCH v9 27/27] MIPS: jz4740: Drop obsolete code Paul Cercueil
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