From: Geert Uytterhoeven <geert@linux-m68k.org> To: Linus Walleij <linus.walleij@linaro.org>, Bartosz Golaszewski <bgolaszewski@baylibre.com> Cc: 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 3/5] gpio: Add GPIO Aggregator Date: Tue, 17 Mar 2020 12:32:31 +0100 [thread overview] Message-ID: <CAMuHMdWXJKdD7j6QiRb4fL+fFsyDKpc7aGK-nER=CZd7bxGyPg@mail.gmail.com> (raw) In-Reply-To: <20200218151812.7816-4-geert+renesas@glider.be> On Tue, Feb 18, 2020 at 4:18 PM Geert Uytterhoeven <geert+renesas@glider.be> wrote: > 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. > Currently no mechanism exists to control access to individual GPIOs. > > Hence add a GPIO driver to aggregate existing GPIOs, and expose them as > a new gpiochip. > > This supports the following use cases: > - Aggregating GPIOs using Sysfs > This is useful for implementing access control, and assigning a set > of GPIOs to a specific user or virtual machine. > - Generic GPIO Driver > This is useful for industrial control, where it can provide > userspace access to a simple GPIO-operated device described in DT, > cfr. e.g. spidev for SPI-operated devices. > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- /dev/null > +++ b/drivers/gpio/gpio-aggregator.c > +static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset, > + unsigned long config) > +{ > + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); > + > + chip = fwd->descs[offset]->gdev->chip; > + if (chip->set_config) - chip = fwd->descs[offset]->gdev->chip; - if (chip->set_config) + chip = gpiod_to_chip(fwd->descs[offset]); + if (chip && chip->set_config) > + return chip->set_config(chip, offset, config); This is not correct: offset should be translated, too, i.e. offset = gpio_chip_hwgpio(fwd->descs[offset]); Which adds a new dependency on "gpiolib.h"... Is there a better alternative, than providing a public gpiod_set_config() helper? Thanks! 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: Linus Walleij <linus.walleij@linaro.org>, Bartosz Golaszewski <bgolaszewski@baylibre.com> 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>, Jonathan Corbet <corbet@lwn.net>, Marc Zyngier <marc.zyngier@arm.com>, "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>, "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>, Rob Herring <robh+dt@kernel.org>, Alexander Graf <graf@amazon.com>, Paolo Bonzini <pbonzini@redhat.com>, Harish Jenny K N <harish_kandiga@mentor.com>, Eugeniu Rosca <erosca@de.adit-jv.com> Subject: Re: [PATCH v5 3/5] gpio: Add GPIO Aggregator Date: Tue, 17 Mar 2020 12:32:31 +0100 [thread overview] Message-ID: <CAMuHMdWXJKdD7j6QiRb4fL+fFsyDKpc7aGK-nER=CZd7bxGyPg@mail.gmail.com> (raw) In-Reply-To: <20200218151812.7816-4-geert+renesas@glider.be> On Tue, Feb 18, 2020 at 4:18 PM Geert Uytterhoeven <geert+renesas@glider.be> wrote: > 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. > Currently no mechanism exists to control access to individual GPIOs. > > Hence add a GPIO driver to aggregate existing GPIOs, and expose them as > a new gpiochip. > > This supports the following use cases: > - Aggregating GPIOs using Sysfs > This is useful for implementing access control, and assigning a set > of GPIOs to a specific user or virtual machine. > - Generic GPIO Driver > This is useful for industrial control, where it can provide > userspace access to a simple GPIO-operated device described in DT, > cfr. e.g. spidev for SPI-operated devices. > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- /dev/null > +++ b/drivers/gpio/gpio-aggregator.c > +static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset, > + unsigned long config) > +{ > + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); > + > + chip = fwd->descs[offset]->gdev->chip; > + if (chip->set_config) - chip = fwd->descs[offset]->gdev->chip; - if (chip->set_config) + chip = gpiod_to_chip(fwd->descs[offset]); + if (chip && chip->set_config) > + return chip->set_config(chip, offset, config); This is not correct: offset should be translated, too, i.e. offset = gpio_chip_hwgpio(fwd->descs[offset]); Which adds a new dependency on "gpiolib.h"... Is there a better alternative, than providing a public gpiod_set_config() helper? Thanks! 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:[~2020-03-17 11:32 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 [this message] 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 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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