From: Geert Uytterhoeven <geert@linux-m68k.org> To: Randy Dunlap <rdunlap@infradead.org> Cc: Geert Uytterhoeven <geert+renesas@glider.be>, Linus Walleij <linus.walleij@linaro.org>, Bartosz Golaszewski <bgolaszewski@baylibre.com>, Jonathan Corbet <corbet@lwn.net>, Harish Jenny K N <harish_kandiga@mentor.com>, Eugeniu Rosca <erosca@de.adit-jv.com>, Alexander Graf <graf@amazon.com>, Peter Maydell <peter.maydell@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Phil Reid <preid@electromag.com.au>, Marc Zyngier <marc.zyngier@arm.com>, Christoffer Dall <christoffer.dall@arm.com>, Magnus Damm <magnus.damm@gmail.com>, Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>, "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>, "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>, Linux-Renesas <linux-renesas-soc@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, QEMU Developers <qemu-devel@nongnu.org> Subject: Re: [PATCH v5 4/5] docs: gpio: Add GPIO Aggregator documentation Date: Fri, 21 Feb 2020 17:34:02 +0100 [thread overview] Message-ID: <CAMuHMdUFV0nbfrpxY60av2x+UUN62wDiVLbcEG83133aqfFcUQ@mail.gmail.com> (raw) In-Reply-To: <e2530fff-a17c-ae90-ba92-360b828582da@infradead.org> Hi Randy, On Tue, Feb 18, 2020 at 7:30 PM Randy Dunlap <rdunlap@infradead.org> wrote: > On 2/18/20 7:18 AM, Geert Uytterhoeven wrote: > > Document the GPIO Aggregator, and the two typical use-cases. > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > > --- /dev/null > > +++ b/Documentation/admin-guide/gpio/gpio-aggregator.rst > > @@ -0,0 +1,102 @@ > > +.. SPDX-License-Identifier: GPL-2.0-only > > + > > +GPIO Aggregator > > +=============== > > + > > +The GPIO Aggregator allows to aggregate GPIOs, and expose them as a new > > "allows" really wants an object following the verb [although the kernel sources > and docs have many cases of it not having an object]. Something like > > allows {you, one, someone, users, a user} to aggregate Changing to: provides a mechanism to aggregate GPIOs > > +gpio_chip. This supports the following use cases. > > + > > + > > +Aggregating GPIOs using Sysfs > > +----------------------------- > > + > > +GPIO controllers are exported to userspace using /dev/gpiochip* character > > +devices. Access control to these devices is provided by standard UNIX file > > +system permissions, on an all-or-nothing basis: either a GPIO controller is > > +accessible for a user, or it is not. > > + > > +The GPIO Aggregator allows access control for individual GPIOs, by aggregating Changing to: provides access control for a set of one or more GPIOs > > +them into a new gpio_chip, which can be assigned to a group or user using > > +standard UNIX file ownership and permissions. Furthermore, this simplifies and > > +hardens exporting GPIOs to a virtual machine, as the VM can just grab the full > > +GPIO controller, and no longer needs to care about which GPIOs to grab and > > +which not, reducing the attack surface. > > +Generic GPIO Driver > > +------------------- > > + > > +The GPIO Aggregator can also be used as a generic driver for a simple > > +GPIO-operated device described in DT, without a dedicated in-kernel driver. > > +This is useful in industrial control, and is not unlike e.g. spidev, which > > +allows to communicate with an SPI device from userspace. > > allows {choose an object} to communicate Changing to: allows the user to communicate Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
WARNING: multiple messages have this Message-ID (diff)
From: Geert Uytterhoeven <geert@linux-m68k.org> To: Randy Dunlap <rdunlap@infradead.org> Cc: Mark Rutland <mark.rutland@arm.com>, Peter Maydell <peter.maydell@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>, Phil Reid <preid@electromag.com.au>, Geert Uytterhoeven <geert+renesas@glider.be>, Jonathan Corbet <corbet@lwn.net>, Marc Zyngier <marc.zyngier@arm.com>, Linus Walleij <linus.walleij@linaro.org>, "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>, Magnus Damm <magnus.damm@gmail.com>, Christoffer Dall <christoffer.dall@arm.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Linux-Renesas <linux-renesas-soc@vger.kernel.org>, Bartosz Golaszewski <bgolaszewski@baylibre.com>, Rob Herring <robh+dt@kernel.org>, Harish Jenny K N <harish_kandiga@mentor.com>, "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>, Alexander Graf <graf@amazon.com>, Eugeniu Rosca <erosca@de.adit-jv.com> Subject: Re: [PATCH v5 4/5] docs: gpio: Add GPIO Aggregator documentation Date: Fri, 21 Feb 2020 17:34:02 +0100 [thread overview] Message-ID: <CAMuHMdUFV0nbfrpxY60av2x+UUN62wDiVLbcEG83133aqfFcUQ@mail.gmail.com> (raw) In-Reply-To: <e2530fff-a17c-ae90-ba92-360b828582da@infradead.org> Hi Randy, On Tue, Feb 18, 2020 at 7:30 PM Randy Dunlap <rdunlap@infradead.org> wrote: > On 2/18/20 7:18 AM, Geert Uytterhoeven wrote: > > Document the GPIO Aggregator, and the two typical use-cases. > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > > --- /dev/null > > +++ b/Documentation/admin-guide/gpio/gpio-aggregator.rst > > @@ -0,0 +1,102 @@ > > +.. SPDX-License-Identifier: GPL-2.0-only > > + > > +GPIO Aggregator > > +=============== > > + > > +The GPIO Aggregator allows to aggregate GPIOs, and expose them as a new > > "allows" really wants an object following the verb [although the kernel sources > and docs have many cases of it not having an object]. Something like > > allows {you, one, someone, users, a user} to aggregate Changing to: provides a mechanism to aggregate GPIOs > > +gpio_chip. This supports the following use cases. > > + > > + > > +Aggregating GPIOs using Sysfs > > +----------------------------- > > + > > +GPIO controllers are exported to userspace using /dev/gpiochip* character > > +devices. Access control to these devices is provided by standard UNIX file > > +system permissions, on an all-or-nothing basis: either a GPIO controller is > > +accessible for a user, or it is not. > > + > > +The GPIO Aggregator allows access control for individual GPIOs, by aggregating Changing to: provides access control for a set of one or more GPIOs > > +them into a new gpio_chip, which can be assigned to a group or user using > > +standard UNIX file ownership and permissions. Furthermore, this simplifies and > > +hardens exporting GPIOs to a virtual machine, as the VM can just grab the full > > +GPIO controller, and no longer needs to care about which GPIOs to grab and > > +which not, reducing the attack surface. > > +Generic GPIO Driver > > +------------------- > > + > > +The GPIO Aggregator can also be used as a generic driver for a simple > > +GPIO-operated device described in DT, without a dedicated in-kernel driver. > > +This is useful in industrial control, and is not unlike e.g. spidev, which > > +allows to communicate with an SPI device from userspace. > > allows {choose an object} to communicate Changing to: allows the user to communicate Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
next prev parent reply other threads:[~2020-02-21 16:34 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-18 15:18 [PATCH v5 0/5] gpio: Add GPIO Aggregator Geert Uytterhoeven 2020-02-18 15:18 ` Geert Uytterhoeven 2020-02-18 15:18 ` [PATCH v5 1/5] gpiolib: Add support for gpiochipN-based table lookup Geert Uytterhoeven 2020-02-18 15:18 ` Geert Uytterhoeven 2020-03-12 14:23 ` Linus Walleij 2020-03-12 14:23 ` Linus Walleij 2020-03-17 8:41 ` Geert Uytterhoeven 2020-03-17 8:41 ` Geert Uytterhoeven 2020-02-18 15:18 ` [PATCH v5 2/5] gpiolib: Add support for GPIO line " Geert Uytterhoeven 2020-02-18 15:18 ` Geert Uytterhoeven 2020-02-19 10:17 ` Geert Uytterhoeven 2020-02-19 10:17 ` Geert Uytterhoeven 2020-03-12 14:21 ` Linus Walleij 2020-03-12 14:21 ` Linus Walleij 2020-03-17 8:48 ` Geert Uytterhoeven 2020-03-17 8:48 ` Geert Uytterhoeven 2020-02-18 15:18 ` [PATCH v5 3/5] gpio: Add GPIO Aggregator Geert Uytterhoeven 2020-02-18 15:18 ` Geert Uytterhoeven 2020-03-12 14:57 ` Linus Walleij 2020-03-12 14:57 ` Linus Walleij 2020-03-17 10:50 ` Geert Uytterhoeven 2020-03-17 10:50 ` Geert Uytterhoeven 2020-03-17 11:32 ` Geert Uytterhoeven 2020-03-17 11:32 ` Geert Uytterhoeven 2020-02-18 15:18 ` [PATCH v5 4/5] docs: gpio: Add GPIO Aggregator documentation Geert Uytterhoeven 2020-02-18 15:18 ` Geert Uytterhoeven 2020-02-18 18:29 ` Randy Dunlap 2020-02-18 18:29 ` Randy Dunlap 2020-02-18 19:09 ` Geert Uytterhoeven 2020-02-18 19:09 ` Geert Uytterhoeven 2020-02-21 16:34 ` Geert Uytterhoeven [this message] 2020-02-21 16:34 ` Geert Uytterhoeven 2020-02-21 16:35 ` Randy Dunlap 2020-02-21 16:35 ` Randy Dunlap 2020-02-18 15:18 ` [PATCH v5 5/5] MAINTAINERS: Add GPIO Aggregator section Geert Uytterhoeven 2020-02-18 15:18 ` Geert Uytterhoeven 2020-02-18 17:04 ` [PATCH v5 0/5] gpio: Add GPIO Aggregator Eugeniu Rosca 2020-02-18 17:04 ` Eugeniu Rosca 2020-02-21 16:39 ` Geert Uytterhoeven 2020-02-21 16:39 ` Geert Uytterhoeven
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