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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>,
	Geert Uytterhoeven <geert+renesas@glider.be>
Subject: Re: [PATCH v5 2/5] gpiolib: Add support for GPIO line table lookup
Date: Wed, 19 Feb 2020 11:17:00 +0100
Message-ID: <CAMuHMdVzkN5c1P3=xD5BzC=R-O8fWJfMRdDtWxcTLO0TUy5n1Q@mail.gmail.com> (raw)
In-Reply-To: <20200218151812.7816-3-geert+renesas@glider.be>

On Tue, Feb 18, 2020 at 4:18 PM Geert Uytterhoeven
<geert+renesas@glider.be> wrote:
> Currently GPIOs can only be referred to by GPIO controller and offset in
> GPIO lookup tables.
>
> Add support for looking them up by line name.
> Rename gpiod_lookup.chip_label to gpiod_lookup.key, to make it clear
> that this field can have two meanings, and update the kerneldoc and
> GPIO_LOOKUP*() macros.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
> Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
> Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>

> --- a/include/linux/gpio/machine.h
> +++ b/include/linux/gpio/machine.h
> @@ -20,8 +20,9 @@ enum gpio_lookup_flags {
>
>  /**
>   * struct gpiod_lookup - lookup table
> - * @chip_label: name of the chip the GPIO belongs to
> - * @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO
> + * @key: either the name of the chip the GPIO belongs to, or the GPIO line name
> + * @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO, or
> + *              U16_MAX to indicate that @key is a GPIO line name
>   * @con_id: name of the GPIO from the device's point of view
>   * @idx: index of the GPIO in case several GPIOs share the same name
>   * @flags: bitmask of gpio_lookup_flags GPIO_* values
> @@ -30,7 +31,7 @@ enum gpio_lookup_flags {
>   * functions using platform data.
>   */
>  struct gpiod_lookup {
> -       const char *chip_label;
> +       const char *key;
>         u16 chip_hwnum;
>         const char *con_id;
>         unsigned int idx;

This needs an update in the documentation:

--- a/Documentation/driver-api/gpio/board.rst
+++ b/Documentation/driver-api/gpio/board.rst
@@ -113,13 +113,15 @@ files that desire to do so need to include the
following header::
 GPIOs are mapped by the means of tables of lookups, containing instances of the
 gpiod_lookup structure. Two macros are defined to help declaring such
mappings::

-       GPIO_LOOKUP(chip_label, chip_hwnum, con_id, flags)
-       GPIO_LOOKUP_IDX(chip_label, chip_hwnum, con_id, idx, flags)
+       GPIO_LOOKUP(key, chip_hwnum, con_id, flags)
+       GPIO_LOOKUP_IDX(key, chip_hwnum, con_id, idx, flags)

 where

-  - chip_label is the label of the gpiod_chip instance providing the GPIO
-  - chip_hwnum is the hardware number of the GPIO within the chip
+  - key is either the label of the gpiod_chip instance providing the GPIO, or
+    the GPIO line name
+  - chip_hwnum is the hardware number of the GPIO within the chip, or U16_MAX
+    to indicate that key is a GPIO line name
   - con_id is the name of the GPIO function from the device point of view. It
        can be NULL, in which case it will match any function.
   - idx is the index of the GPIO within the function.


Furthermore, a few drivers populate the gpiod_lookup members directly,
instead of using the convenience macros:

    arch/arm/mach-integrator/impd1.c
    drivers/i2c/busses/i2c-i801.c
    drivers/mfd/sm501.c

Either they have to be updated s/chip_label/key/, or start using the macros,
e.g.

--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1444,9 +1444,9 @@ static int i801_add_mux(struct i801_priv *priv)
                return -ENOMEM;
        lookup->dev_id = "i2c-mux-gpio";
        for (i = 0; i < mux_config->n_gpios; i++) {
-               lookup->table[i].chip_label = mux_config->gpio_chip;
-               lookup->table[i].chip_hwnum = mux_config->gpios[i];
-               lookup->table[i].con_id = "mux";
+               lookup->table[i] = (struct gpiod_lookup)
+                       GPIO_LOOKUP(mux_config->gpio_chip,
+                                   mux_config->gpios[i], "mux", 0);
        }
        gpiod_add_lookup_table(lookup);
        priv->lookup = lookup;

Do you have any preference?
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

  reply index

Thread overview: 20+ 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 ` [PATCH v5 1/5] gpiolib: Add support for gpiochipN-based table lookup Geert Uytterhoeven
2020-03-12 14:23   ` Linus Walleij
2020-03-17  8:41     ` Geert Uytterhoeven
2020-02-18 15:18 ` [PATCH v5 2/5] gpiolib: Add support for GPIO line " Geert Uytterhoeven
2020-02-19 10:17   ` Geert Uytterhoeven [this message]
2020-03-12 14:21   ` Linus Walleij
2020-03-17  8:48     ` Geert Uytterhoeven
2020-02-18 15:18 ` [PATCH v5 3/5] gpio: Add GPIO Aggregator Geert Uytterhoeven
2020-03-12 14:57   ` Linus Walleij
2020-03-17 10:50     ` 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 18:29   ` Randy Dunlap
2020-02-18 19:09     ` Geert Uytterhoeven
2020-02-21 16:34     ` Geert Uytterhoeven
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 17:04 ` [PATCH v5 0/5] gpio: Add GPIO Aggregator Eugeniu Rosca
2020-02-21 16:39 ` Geert Uytterhoeven

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