From: Thierry Reding <thierry.reding@gmail.com>
To: "Vokáč Michal" <Michal.Vokac@ysoft.com>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-pwm@vger.kernel.org" <linux-pwm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Lukasz Majewski" <l.majewski@majess.pl>,
"Fabio Estevam" <fabio.estevam@nxp.com>,
"Lothar Waßmann" <LW@karo-electronics.de>,
"kernel@pengutronix.de" <kernel@pengutronix.de>
Subject: Re: [RCF PATCH,v2,2/2] pwm: imx: Configure output to GPIO in disabled state
Date: Fri, 12 Oct 2018 17:54:59 +0200 [thread overview]
Message-ID: <20181012155459.GG31561@ulmo> (raw)
In-Reply-To: <fa96ae2a-c2cc-b47a-1198-5daffa7c865f@ysoft.com>
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On Fri, Oct 12, 2018 at 03:04:48PM +0000, Vokáč Michal wrote:
> On 12.10.2018 10:57, Uwe Kleine-König wrote:
> > On Wed, Oct 10, 2018 at 09:33:26AM +0000, Vokáč Michal wrote:
[...]
> >> +static int imx_pwm_init_pinctrl_info(struct imx_chip *imx_chip,
> >> + struct platform_device *pdev)
> >> +{
> >> + imx_chip->pinctrl = devm_pinctrl_get(&pdev->dev);
> >> + if (!imx_chip->pinctrl || IS_ERR(imx_chip->pinctrl)) {
> >> + dev_info(&pdev->dev, "can not get pinctrl\n");
> >> + return PTR_ERR(imx_chip->pinctrl);
> >> + }
> >> +
> >> + imx_chip->pinctrl_pins_pwm = pinctrl_lookup_state(imx_chip->pinctrl,
> >> + "pwm");
> >> + imx_chip->pinctrl_pins_gpio = pinctrl_lookup_state(imx_chip->pinctrl,
> >> + "gpio");
> >> + imx_chip->pwm_gpiod = devm_gpiod_get_optional(&pdev->dev, "pwm",
> >> + GPIOD_IN);
> >> +
> >> + if (PTR_ERR(imx_chip->pwm_gpiod) == -EPROBE_DEFER) {
> >
> > You must not use PTR_ERR on a value that might not contain an error
> > pointer.
>
> OK, thank you for valuable info.
> So it seems like the I2C folks are in troubles as well:
>
> https://elixir.bootlin.com/linux/latest/source/drivers/i2c/busses/i2c-imx.c#L996
There's nothing inherently wrong with doing it like the above, just
maybe slightly unusual. PTR_ERR() is really just casting from a pointer
to an integer, so if the pointer happens to contain the value
-EPROBE_DEFER, then the above will be true. If it contains a valid
pointer, the above will be false, so it does exactly what you want.
Perhaps a more idiomatic way to write this would be:
if (IS_ERR(imx_chip->pwm_gpiod)) {
if (PTR_ERR(imx_chip->pwm_gpiod) == -EPROBE_DEFER)
return -EPROBE_DEFER;
}
But that's not much clearer than what you have, so feel free to keep it
that way.
Thierry
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next prev parent reply other threads:[~2018-10-12 15:55 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 9:33 [RCF PATCH v2 0/2] pwm: imx: Configure output to GPIO in disabled state Vokáč Michal
2018-10-10 9:33 ` [RCF PATCH v2 1/2] dt-bindings: pwm: imx: Allow switching PWM output between PWM and GPIO Vokáč Michal
2018-10-10 13:39 ` Thierry Reding
2018-10-29 15:52 ` Vokáč Michal
2018-10-10 9:33 ` [RCF PATCH v2 2/2] pwm: imx: Configure output to GPIO in disabled state Vokáč Michal
2018-10-12 8:57 ` [RCF PATCH,v2,2/2] " Uwe Kleine-König
2018-10-12 15:04 ` Vokáč Michal
2018-10-12 15:54 ` Thierry Reding [this message]
2018-10-12 16:08 ` Uwe Kleine-König
2018-10-14 20:24 ` Uwe Kleine-König
2018-10-15 8:45 ` Thierry Reding
2018-10-29 15:55 ` Vokáč Michal
2018-10-29 15:54 ` Vokáč Michal
2018-11-07 9:33 ` Uwe Kleine-König
2018-11-07 13:32 ` Vokáč Michal
2018-11-07 15:01 ` Uwe Kleine-König
2018-11-08 15:21 ` Vokáč Michal
2018-11-08 19:18 ` Uwe Kleine-König
2018-11-09 14:24 ` Vokáč Michal
2018-11-09 16:55 ` Uwe Kleine-König
2018-11-14 9:09 ` Uwe Kleine-König
2018-11-14 11:34 ` Thierry Reding
2018-11-14 21:51 ` Uwe Kleine-König
2018-11-15 15:25 ` Thierry Reding
2018-11-15 20:37 ` Uwe Kleine-König
2018-11-16 7:34 ` Lothar Waßmann
2018-11-16 8:25 ` Uwe Kleine-König
2018-11-22 15:42 ` Vokáč Michal
2018-11-22 16:23 ` Uwe Kleine-König
2018-11-22 16:46 ` Vokáč Michal
2018-11-22 19:03 ` Uwe Kleine-König
2018-11-23 15:15 ` Vokáč Michal
2018-11-25 20:56 ` Uwe Kleine-König
2018-11-26 9:11 ` Lothar Waßmann
2018-11-26 9:18 ` Uwe Kleine-König
2018-11-26 10:03 ` Lothar Waßmann
2018-11-26 11:51 ` Thierry Reding
2018-11-26 12:23 ` Lothar Waßmann
2018-11-26 13:34 ` Thierry Reding
2018-11-26 15:50 ` Vokáč Michal
2018-11-16 9:51 ` Thierry Reding
2018-11-16 10:39 ` Uwe Kleine-König
2018-11-16 11:56 ` Lothar Waßmann
2018-11-18 11:30 ` Uwe Kleine-König
2018-11-16 12:24 ` Thierry Reding
2018-11-18 20:08 ` Uwe Kleine-König
2018-11-19 8:48 ` Uwe Kleine-König
2018-11-22 15:03 ` Thierry Reding
2018-11-22 16:17 ` Uwe Kleine-König
2018-11-20 13:14 ` Vokáč Michal
2018-11-20 16:54 ` Uwe Kleine-König
2018-11-22 14:23 ` Vokáč Michal
2018-11-19 7:44 ` Linus Walleij
2018-11-19 8:32 ` Uwe Kleine-König
2018-11-20 8:35 ` Linus Walleij
2018-11-20 9:16 ` Viresh Kumar
2018-11-20 9:53 ` Uwe Kleine-König
2018-11-14 11:14 ` Thierry Reding
2018-10-12 16:00 ` [RCF PATCH v2 2/2] " Thierry Reding
2018-10-29 15:53 ` Vokáč Michal
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