From: "Clément Péron" <peron.clem@gmail.com>
To: Philipp Zabel <pza@pengutronix.de>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Chen-Yu Tsai" <wens@csie.org>,
linux-pwm@vger.kernel.org,
devicetree <devicetree@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
"Jernej Skrabec" <jernej.skrabec@siol.net>
Subject: Re: [PATCH v2 2/7] pwm: sun4i: Add an optional probe for reset line
Date: Tue, 5 Nov 2019 14:03:29 +0100 [thread overview]
Message-ID: <CAJiuCccYoD=3Fw+NrkoCipYp8S=pSHUq9hFOxzNg51J=hUx16A@mail.gmail.com> (raw)
In-Reply-To: <20191105070128.ve73ha5ibiymcxnx@pengutronix.de>
Hi Philipp,
On Tue, 5 Nov 2019 at 08:01, Philipp Zabel <pza@pengutronix.de> wrote:
>
> On Mon, Nov 04, 2019 at 09:11:57AM +0100, Uwe Kleine-König wrote:
> > Hello,
> >
> > adding Philipp Zabel (= reset controller maintainer) to Cc: and so I'm
> > not stripping the uncommented parts of the patch.
> >
> > On Sun, Nov 03, 2019 at 09:33:29PM +0100, Clément Péron wrote:
> > > From: Jernej Skrabec <jernej.skrabec@siol.net>
> > >
> > > H6 PWM core needs deasserted reset line in order to work.
> > >
> > > Add an optional probe for it.
> > >
> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > > Signed-off-by: Clément Péron <peron.clem@gmail.com>
> > > ---
> > > drivers/pwm/pwm-sun4i.c | 32 ++++++++++++++++++++++++++++++--
> > > 1 file changed, 30 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
> > > index 6f5840a1a82d..d194b8ebdb00 100644
> > > --- a/drivers/pwm/pwm-sun4i.c
> > > +++ b/drivers/pwm/pwm-sun4i.c
> > > @@ -16,6 +16,7 @@
> > > #include <linux/of_device.h>
> > > #include <linux/platform_device.h>
> > > #include <linux/pwm.h>
> > > +#include <linux/reset.h>
> > > #include <linux/slab.h>
> > > #include <linux/spinlock.h>
> > > #include <linux/time.h>
> > > @@ -78,6 +79,7 @@ struct sun4i_pwm_data {
> > > struct sun4i_pwm_chip {
> > > struct pwm_chip chip;
> > > struct clk *clk;
> > > + struct reset_control *rst;
> > > void __iomem *base;
> > > spinlock_t ctrl_lock;
> > > const struct sun4i_pwm_data *data;
> > > @@ -365,6 +367,20 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
> > > if (IS_ERR(pwm->clk))
> > > return PTR_ERR(pwm->clk);
> > >
> > > + pwm->rst = devm_reset_control_get_optional(&pdev->dev, NULL);
> > > + if (IS_ERR(pwm->rst)) {
> > > + if (PTR_ERR(pwm->rst) == -EPROBE_DEFER)
> > > + return PTR_ERR(pwm->rst);
> > > + dev_info(&pdev->dev, "no reset control found\n");
> >
> > I would degrade this to a dev_dbg. Otherwise this spams the log for all
> > unaffected machines.
>
> The _optional variants return NULL if the reset is not specified in the
> device tree, so this is not "no reset control found", but a real error
> that should be returned.
Correct,
Thanks for the catch,
Clément
>
> > devm_reset_control_get_optional() is defined in a section that has a
> > comment "These inline function calls will be removed once all
> > consumers have been moved over to the new explicit API.", so I guess
> > you want devm_reset_control_get_optional_exclusive or even
> > devm_reset_control_get_optional_shared here.
>
> Correct. If this driver deasserts in probe() and asserts the reset in
> remove(), this can use the refcounting _shared variant.
>
> > @Philipp: maybe a check in checkpatch that warns about introduction of
> > such new instances would be good?!
>
> Yes, that would be helpful.
>
> regards
> Philipp
next prev parent reply other threads:[~2019-11-05 13:03 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-03 20:33 [PATCH v2 0/7] Add support for H6 PWM Clément Péron
2019-11-03 20:33 ` [PATCH v2 1/7] dt-bindings: pwm: allwinner: Add H6 PWM description Clément Péron
2019-11-04 8:03 ` Uwe Kleine-König
2019-11-04 17:49 ` Clément Péron
2019-11-05 11:11 ` Maxime Ripard
2019-11-05 12:34 ` Clément Péron
2019-11-05 17:32 ` Maxime Ripard
2019-11-06 9:25 ` Clément Péron
2019-11-03 20:33 ` [PATCH v2 2/7] pwm: sun4i: Add an optional probe for reset line Clément Péron
2019-11-04 8:11 ` Uwe Kleine-König
2019-11-04 17:50 ` Clément Péron
2019-11-05 7:01 ` Philipp Zabel
2019-11-05 13:03 ` Clément Péron [this message]
2019-11-03 20:33 ` [PATCH v2 3/7] pwm: sun4i: Add an optional probe for bus clock Clément Péron
2019-11-04 8:24 ` Uwe Kleine-König
2019-11-04 18:07 ` Clément Péron
2019-11-04 20:10 ` Uwe Kleine-König
2019-11-04 20:19 ` Jernej Škrabec
2019-11-04 20:27 ` Clément Péron
2019-11-04 20:38 ` Jernej Škrabec
2019-11-03 20:33 ` [PATCH v2 4/7] pwm: sun4i: Add support to output source clock directly Clément Péron
2019-11-03 22:30 ` kbuild test robot
2019-11-03 22:41 ` Clément Péron
2019-11-03 22:58 ` kbuild test robot
2019-11-04 8:38 ` Uwe Kleine-König
2019-11-04 21:28 ` Clément Péron
2019-11-05 7:29 ` Uwe Kleine-König
2019-11-05 12:58 ` Clément Péron
2019-11-05 13:12 ` Uwe Kleine-König
2019-11-05 13:12 ` Clément Péron
2019-11-03 20:33 ` [PATCH v2 5/7] pwm: sun4i: Add support for H6 PWM Clément Péron
2019-11-03 20:33 ` [PATCH v2 6/7] arm64: dts: allwinner: h6: Add PWM node Clément Péron
2019-11-03 20:33 ` [PATCH v2 7/7] [DO NOT MERGE] arm64: allwinner: h6: enable Beelink GS1 PWM Clément Péron
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