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From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@bootlin.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: mvebu: switch to using gpiod API in pm-board code
Date: Tue, 15 Nov 2022 17:40:35 -0800	[thread overview]
Message-ID: <Y3Q/k0hoPcnQhS8L@google.com> (raw)
In-Reply-To: <Y3Q4hVn3GEOm4nMq@lunn.ch>

On Wed, Nov 16, 2022 at 02:10:29AM +0100, Andrew Lunn wrote:
> > -		ret = gpio_direction_output(pic_gpios[i], 0);
> > -		if (ret < 0) {
> > -			gpio_free(pic_gpios[i]);
> > +		pic_gpios[i] = fwnode_gpiod_get_index(of_fwnode_handle(np),
> > +						      "ctrl", i, GPIOD_OUT_HIGH,
> > +						      name);
> 
> The old code passes value=0 to gpio_direction_output(). For
> fwnode_gpiod_get_index() you pass GPIOD_OUT_HIGH. Is this correct?

Yes, gpiod API works on logical states, whereas old gpio API used signal
levels. In arch/arm/boot/dts/armada-xp-gp.dts ctrl-gpios are described
as "active low":

	cpus {
		pm_pic {
			ctrl-gpios = <&gpio0 16 GPIO_ACTIVE_LOW>,
				     <&gpio0 17 GPIO_ACTIVE_LOW>,
				     <&gpio0 18 GPIO_ACTIVE_LOW>;
		};
	};

so gpiolib will translate GPIOD_OUT_HIGH to 0 when setting final state
of the pin.

There are discussions to rename GPIOD_OUT_HIGH and friends to something
like active/inactive for better clarity, but that has not happened yet.

Thanks.

-- 
Dmitry

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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@bootlin.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: mvebu: switch to using gpiod API in pm-board code
Date: Tue, 15 Nov 2022 17:40:35 -0800	[thread overview]
Message-ID: <Y3Q/k0hoPcnQhS8L@google.com> (raw)
In-Reply-To: <Y3Q4hVn3GEOm4nMq@lunn.ch>

On Wed, Nov 16, 2022 at 02:10:29AM +0100, Andrew Lunn wrote:
> > -		ret = gpio_direction_output(pic_gpios[i], 0);
> > -		if (ret < 0) {
> > -			gpio_free(pic_gpios[i]);
> > +		pic_gpios[i] = fwnode_gpiod_get_index(of_fwnode_handle(np),
> > +						      "ctrl", i, GPIOD_OUT_HIGH,
> > +						      name);
> 
> The old code passes value=0 to gpio_direction_output(). For
> fwnode_gpiod_get_index() you pass GPIOD_OUT_HIGH. Is this correct?

Yes, gpiod API works on logical states, whereas old gpio API used signal
levels. In arch/arm/boot/dts/armada-xp-gp.dts ctrl-gpios are described
as "active low":

	cpus {
		pm_pic {
			ctrl-gpios = <&gpio0 16 GPIO_ACTIVE_LOW>,
				     <&gpio0 17 GPIO_ACTIVE_LOW>,
				     <&gpio0 18 GPIO_ACTIVE_LOW>;
		};
	};

so gpiolib will translate GPIOD_OUT_HIGH to 0 when setting final state
of the pin.

There are discussions to rename GPIOD_OUT_HIGH and friends to something
like active/inactive for better clarity, but that has not happened yet.

Thanks.

-- 
Dmitry

  reply	other threads:[~2022-11-16  1:43 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-15 23:12 [PATCH] ARM: mvebu: switch to using gpiod API in pm-board code Dmitry Torokhov
2022-11-15 23:12 ` Dmitry Torokhov
2022-11-16  1:10 ` Andrew Lunn
2022-11-16  1:10   ` Andrew Lunn
2022-11-16  1:40   ` Dmitry Torokhov [this message]
2022-11-16  1:40     ` Dmitry Torokhov
2022-11-16  2:03     ` Andrew Lunn
2022-11-16  2:03       ` Andrew Lunn
2022-11-16  2:03 ` Andrew Lunn
2022-11-16  2:03   ` Andrew Lunn
2022-11-28  0:13 ` Gregory CLEMENT
2022-11-28  0:13   ` Gregory CLEMENT

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