Re: [PATCH 15/21] dsa: b53: hide legacy gpiolib usage on non-mips

[Jonas Gorski <jonas.gorski@gmail.com>]

Hi,

On Fri, Aug 8, 2025 at 5:23 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> The MIPS bcm53xx platform still uses the legacy gpiolib interfaces based
> on gpio numbers, but other platforms do not.
>
> Hide these interfaces inside of the existing #ifdef block and use the
> modern interfaces in the common parts of the driver to allow building
> it when the gpio_set_value() is left out of the kernel.

Looks reasonable, but doesn't compile:

  CC      drivers/net/dsa/b53/b53_spi.o
In file included from drivers/net/dsa/b53/b53_spi.c:27:
drivers/net/dsa/b53/b53_priv.h:378:15: error: unknown type name 'gpio_desc'
  378 | static inline gpio_desc *b53_switch_get_reset_gpio(struct
b53_device *dev)
      |               ^~~~~~~~~
drivers/net/dsa/b53/b53_priv.h: In function 'b53_switch_get_reset_gpio':
drivers/net/dsa/b53/b53_priv.h:392:14: error: implicit declaration of
function 'gpio_is_valid'; did you mean 'uuid_is_valid'?
[-Wimplicit-function-declaration]
  392 |         if (!gpio_is_valid(gpio))
      |              ^~~~~~~~~~~~~
      |              uuid_is_valid
drivers/net/dsa/b53/b53_priv.h:395:15: error: implicit declaration of
function 'devm_gpiod_request_one' [-Wimplicit-function-declaration]
  395 |         ret = devm_gpiod_request_one(dev->dev, gpio,
      |               ^~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/b53/b53_priv.h:396:38: error: 'GPIOF_OUT_INIT_HIGH'
undeclared (first use in this function); did you mean
'GPIOD_OUT_HIGH'?
  396 |                                      GPIOF_OUT_INIT_HIGH, "robo_reset");
      |                                      ^~~~~~~~~~~~~~~~~~~
      |                                      GPIOD_OUT_HIGH
drivers/net/dsa/b53/b53_priv.h:396:38: note: each undeclared
identifier is reported only once for each function it appears in
drivers/net/dsa/b53/b53_priv.h:400:16: error: returning 'struct
gpio_desc *' from a function with incompatible return type 'int *'
[-Wincompatible-pointer-types]
  400 |         return gpio_to_desc(gpio);
      |                ^~~~~~~~~~~~~~~~~~

>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/net/dsa/b53/b53_common.c | 17 +++++------------
>  drivers/net/dsa/b53/b53_priv.h   | 24 ++++++++++++++++++------
>  2 files changed, 23 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
> index 9942fb6f7f4b..cb57bcc56c63 100644
> --- a/drivers/net/dsa/b53/b53_common.c
> +++ b/drivers/net/dsa/b53/b53_common.c
> @@ -19,7 +19,7 @@
>
>  #include <linux/delay.h>
>  #include <linux/export.h>
> -#include <linux/gpio.h>

this include is now needed for b53_priv.h.

> +#include <linux/gpio/consumer.h>
>  #include <linux/kernel.h>
>  #include <linux/math.h>
>  #include <linux/minmax.h>
> @@ -948,17 +948,17 @@ EXPORT_SYMBOL(b53_configure_vlan);
>
>  static void b53_switch_reset_gpio(struct b53_device *dev)
>  {
> -       int gpio = dev->reset_gpio;
> +       struct gpio_desc *gpio = dev->reset_gpio;
>
> -       if (gpio < 0)
> +       if (IS_ERR(gpio))
>                 return;
>
>         /* Reset sequence: RESET low(50ms)->high(20ms)
>          */
> -       gpio_set_value(gpio, 0);
> +       gpiod_set_value(gpio, 0);
>         mdelay(50);
>
> -       gpio_set_value(gpio, 1);
> +       gpiod_set_value(gpio, 1);
>         mdelay(20);
>
>         dev->current_page = 0xff;
> @@ -2925,7 +2925,6 @@ static int b53_switch_init(struct b53_device *dev)
>  {
>         u32 chip_id = dev->chip_id;
>         unsigned int i;
> -       int ret;
>
>         if (is63xx(dev))
>                 chip_id = BCM63XX_DEVICE_ID;
> @@ -3005,12 +3004,6 @@ static int b53_switch_init(struct b53_device *dev)
>                 return -ENOMEM;
>
>         dev->reset_gpio = b53_switch_get_reset_gpio(dev);
> -       if (dev->reset_gpio >= 0) {
> -               ret = devm_gpio_request_one(dev->dev, dev->reset_gpio,
> -                                           GPIOF_OUT_INIT_HIGH, "robo_reset");
> -               if (ret)
> -                       return ret;
> -       }
>
>         return 0;
>  }
> diff --git a/drivers/net/dsa/b53/b53_priv.h b/drivers/net/dsa/b53/b53_priv.h
> index 458775f95164..16e82653a7c6 100644
> --- a/drivers/net/dsa/b53/b53_priv.h
> +++ b/drivers/net/dsa/b53/b53_priv.h
> @@ -136,7 +136,7 @@ struct b53_device {
>         u8 duplex_reg;
>         u8 jumbo_pm_reg;
>         u8 jumbo_size_reg;
> -       int reset_gpio;
> +       struct gpio_desc *reset_gpio;
>         u8 num_arl_bins;
>         u16 num_arl_buckets;
>         enum dsa_tag_protocol tag_protocol;
> @@ -375,22 +375,34 @@ static inline void b53_arl_from_entry_25(u64 *mac_vid,
>
>  #include <linux/bcm47xx_nvram.h>
>  #include <bcm47xx_board.h>
> -static inline int b53_switch_get_reset_gpio(struct b53_device *dev)
> +static inline gpio_desc *b53_switch_get_reset_gpio(struct b53_device *dev)

s/gpio_desc/struct gpio_desc/

>  {
>         enum bcm47xx_board board = bcm47xx_board_get();
> +       int gpio, ret;
>
>         switch (board) {
>         case BCM47XX_BOARD_LINKSYS_WRT300NV11:
>         case BCM47XX_BOARD_LINKSYS_WRT310NV1:
> -               return 8;
> +               gpio = 8;
> +               break;
>         default:
> -               return bcm47xx_nvram_gpio_pin("robo_reset");
> +               gpio = bcm47xx_nvram_gpio_pin("robo_reset");
>         }
> +
> +       if (!gpio_is_valid(gpio))
> +               return ERR_PTR(-EINVAL);
> +
> +       ret = devm_gpiod_request_one(dev->dev, gpio,

s/devm_gpiod_request_one/devm_gpio_request_one/

> +                                    GPIOF_OUT_INIT_HIGH, "robo_reset");
> +       if (ret)
> +               return ERR_PTR(ret);
> +
> +       return gpio_to_desc(gpio);
>  }
>  #else
> -static inline int b53_switch_get_reset_gpio(struct b53_device *dev)
> +static inline struct gpio_desc *b53_switch_get_reset_gpio(struct b53_device *dev)
>  {
> -       return -ENOENT;
> +       return ERR_PTR(-ENODEV);
>  }
>  #endif

Can't really test this (no matching hardware), but with the code issues fixed

Reviewed-by: Jonas Gorski <jonas.gorski@gmail.com>

Best regards,
Jonas