Re: [PATCH v2 1/3] gpio: defer probe if pinctrl cannot be found

[Tomeu Vizoso <tomeu.vizoso@collabora.com>]

On 14 July 2015 at 10:29, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> When an OF node has a pin range for its GPIOs, return -EPROBE_DEFER if
> the pin controller isn't available.
>
> Otherwise, the GPIO range wouldn't be set at all unless the pin
> controller probed always before the GPIO chip.
>
> With this change, the probe of the GPIO chip will be deferred and will
> be retried at a later point, hopefully once the pin controller has been
> registered and probed already.

Ping :)

Thanks,

Tomeu

> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> ---
>
> Changes in v2:
> - Don't defer probe if the pinctrl node is disabled
>
>  drivers/gpio/gpiolib-of.c | 27 ++++++++++++++++++---------
>  drivers/gpio/gpiolib.c    |  5 ++++-
>  include/linux/of_gpio.h   |  4 ++--
>  3 files changed, 24 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
> index 9a0ec48a4737..4e1f73b9136a 100644
> --- a/drivers/gpio/gpiolib-of.c
> +++ b/drivers/gpio/gpiolib-of.c
> @@ -338,7 +338,7 @@ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
>  EXPORT_SYMBOL(of_mm_gpiochip_remove);
>
>  #ifdef CONFIG_PINCTRL
> -static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
> +static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
>  {
>         struct device_node *np = chip->of_node;
>         struct of_phandle_args pinspec;
> @@ -349,7 +349,7 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
>         struct property *group_names;
>
>         if (!np)
> -               return;
> +               return 0;
>
>         group_names = of_find_property(np, group_names_propname, NULL);
>
> @@ -361,7 +361,7 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
>
>                 pctldev = of_pinctrl_get(pinspec.np);
>                 if (!pctldev)
> -                       break;
> +                       return -EPROBE_DEFER;
>
>                 if (pinspec.args[2]) {
>                         if (group_names) {
> @@ -381,7 +381,7 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
>                                         pinspec.args[1],
>                                         pinspec.args[2]);
>                         if (ret)
> -                               break;
> +                               return ret;
>                 } else {
>                         /* npins == 0: special range */
>                         if (pinspec.args[1]) {
> @@ -411,32 +411,41 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
>                         ret = gpiochip_add_pingroup_range(chip, pctldev,
>                                                 pinspec.args[0], name);
>                         if (ret)
> -                               break;
> +                               return ret;
>                 }
>         }
> +
> +       return 0;
>  }
>
>  #else
> -static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
> +static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
>  #endif
>
> -void of_gpiochip_add(struct gpio_chip *chip)
> +int of_gpiochip_add(struct gpio_chip *chip)
>  {
> +       int status;
> +
>         if ((!chip->of_node) && (chip->dev))
>                 chip->of_node = chip->dev->of_node;
>
>         if (!chip->of_node)
> -               return;
> +               return 0;
>
>         if (!chip->of_xlate) {
>                 chip->of_gpio_n_cells = 2;
>                 chip->of_xlate = of_gpio_simple_xlate;
>         }
>
> -       of_gpiochip_add_pin_range(chip);
> +       status = of_gpiochip_add_pin_range(chip);
> +       if (status)
> +               return status;
> +
>         of_node_get(chip->of_node);
>
>         of_gpiochip_scan_hogs(chip);
> +
> +       return 0;
>  }
>
>  void of_gpiochip_remove(struct gpio_chip *chip)
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index bf4bd1d120c3..a8cab335c0cc 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -287,7 +287,10 @@ int gpiochip_add(struct gpio_chip *chip)
>         INIT_LIST_HEAD(&chip->pin_ranges);
>  #endif
>
> -       of_gpiochip_add(chip);
> +       status = of_gpiochip_add(chip);
> +       if (status)
> +               goto err_remove_chip;
> +
>         acpi_gpiochip_add(chip);
>
>         status = gpiochip_sysfs_register(chip);
> diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
> index 69dbe312b11b..f3191828f037 100644
> --- a/include/linux/of_gpio.h
> +++ b/include/linux/of_gpio.h
> @@ -54,7 +54,7 @@ extern int of_mm_gpiochip_add(struct device_node *np,
>                               struct of_mm_gpio_chip *mm_gc);
>  extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
>
> -extern void of_gpiochip_add(struct gpio_chip *gc);
> +extern int of_gpiochip_add(struct gpio_chip *gc);
>  extern void of_gpiochip_remove(struct gpio_chip *gc);
>  extern int of_gpio_simple_xlate(struct gpio_chip *gc,
>                                 const struct of_phandle_args *gpiospec,
> @@ -76,7 +76,7 @@ static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
>         return -ENOSYS;
>  }
>
> -static inline void of_gpiochip_add(struct gpio_chip *gc) { }
> +static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; }
>  static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
>
>  #endif /* CONFIG_OF_GPIO */
> --
> 2.4.3
>