From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: "Timur Tabi" <timur@codeaurora.org>,
"Linus Walleij" <linus.walleij@linaro.org>,
linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
"Antoine Ténart" <antoine.tenart@free-electrons.com>,
"Miquèl Raynal" <miquel.raynal@free-electrons.com>,
"Nadav Haklai" <nadavh@marvell.com>
Subject: Re: linux-next regression caused by "gpiolib: request the gpio before querying its direction"
Date: Wed, 30 Aug 2017 16:17:30 +0200 [thread overview]
Message-ID: <20170830161730.41919554@windsurf.lan> (raw)
In-Reply-To: <87ziah2m3f.fsf@free-electrons.com>
Hello,
On Wed, 30 Aug 2017 15:59:00 +0200, Gregory CLEMENT wrote:
> > When gpiochip_add_data() calls chip->request, what function is that
> > calling?
>
> the request callback is gpiochip_generic_request so I would be surprised
> that there was a bug in it.
The call chain leading to the problem is:
gpiochip_add_data()
chip->request() == gpiochip_generic_request()
pinctrl_request_gpio()
pinmux_request_gpio()
pin_request()
ops->gpio_request_enable() == mvebu_pinmux_gpio_request_enable()
mvebu_pinconf_group_set()
grp->ctrl->mpp_set() == mvebu_regmap_mpp_ctrl_set()
So what Timur is saying perhaps is that
mvebu_pinmux_gpio_request_enable() shouldn't be changing the type of
muxing, and therefore shouldn't be calling mvebu_pinconf_group_set().
However, even the "reference" pinctrl-single.c implementation does it,
in pcs_request_gpio().
Am I missing something ?
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni)
To: linux-arm-kernel@lists.infradead.org
Subject: linux-next regression caused by "gpiolib: request the gpio before querying its direction"
Date: Wed, 30 Aug 2017 16:17:30 +0200 [thread overview]
Message-ID: <20170830161730.41919554@windsurf.lan> (raw)
In-Reply-To: <87ziah2m3f.fsf@free-electrons.com>
Hello,
On Wed, 30 Aug 2017 15:59:00 +0200, Gregory CLEMENT wrote:
> > When gpiochip_add_data() calls chip->request, what function is that
> > calling?
>
> the request callback is gpiochip_generic_request so I would be surprised
> that there was a bug in it.
The call chain leading to the problem is:
gpiochip_add_data()
chip->request() == gpiochip_generic_request()
pinctrl_request_gpio()
pinmux_request_gpio()
pin_request()
ops->gpio_request_enable() == mvebu_pinmux_gpio_request_enable()
mvebu_pinconf_group_set()
grp->ctrl->mpp_set() == mvebu_regmap_mpp_ctrl_set()
So what Timur is saying perhaps is that
mvebu_pinmux_gpio_request_enable() shouldn't be changing the type of
muxing, and therefore shouldn't be calling mvebu_pinconf_group_set().
However, even the "reference" pinctrl-single.c implementation does it,
in pcs_request_gpio().
Am I missing something ?
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
next prev parent reply other threads:[~2017-08-30 14:17 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-30 9:24 linux-next regression caused by "gpiolib: request the gpio before querying its direction" Thomas Petazzoni
2017-08-30 9:24 ` Thomas Petazzoni
2017-08-30 12:31 ` Timur Tabi
2017-08-30 12:31 ` Timur Tabi
2017-08-30 13:59 ` Gregory CLEMENT
2017-08-30 13:59 ` Gregory CLEMENT
2017-08-30 14:17 ` Thomas Petazzoni [this message]
2017-08-30 14:17 ` Thomas Petazzoni
2017-08-30 14:22 ` Timur Tabi
2017-08-30 14:22 ` Timur Tabi
2017-08-30 14:32 ` Thomas Petazzoni
2017-08-30 14:32 ` Thomas Petazzoni
2017-08-30 16:24 ` jmondi
2017-08-30 16:24 ` jmondi
2017-08-30 19:38 ` Geert Uytterhoeven
2017-08-30 19:38 ` Geert Uytterhoeven
2017-08-31 7:08 ` Linus Walleij
2017-08-31 7:08 ` Linus Walleij
2017-08-31 7:18 ` Thomas Petazzoni
2017-08-31 7:18 ` Thomas Petazzoni
2017-08-31 7:30 ` Geert Uytterhoeven
2017-08-31 7:30 ` Geert Uytterhoeven
2017-08-31 9:22 ` Russell King - ARM Linux
2017-08-31 9:22 ` Russell King - ARM Linux
2017-08-31 9:39 ` Thomas Petazzoni
2017-08-31 9:39 ` Thomas Petazzoni
2017-08-31 18:39 ` Timur Tabi
2017-08-31 18:39 ` Timur Tabi
2017-08-31 9:50 ` Geert Uytterhoeven
2017-08-31 9:50 ` Geert Uytterhoeven
2017-08-31 13:05 ` Timur Tabi
2017-08-31 13:05 ` Timur Tabi
2017-08-31 10:08 ` Maxime Ripard
2017-08-31 10:08 ` Maxime Ripard
2017-08-31 7:04 ` Linus Walleij
2017-08-31 7:04 ` Linus Walleij
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