[PATCH] ath79: fix MikroTik CPLD driver build error on kernel 6.1

[Jonas Gorski]

Hi,

On Sat, 9 Sept 2023 at 04:44, Shiji Yang <yangshiji66 at outlook.com> wrote:
>
> From: Shiji Yang <yangshiji66 at qq.com>
>
> Since kernel 5.18, the return type in device remove function has
> changed from 'int' to 'void'.
>
> Signed-off-by: Shiji Yang <yangshiji66 at qq.com>
> ---
>  target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c b/target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c
> index da18424c63..f10ddef9e2 100644
> --- a/target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c
> +++ b/target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c
> @@ -22,6 +22,7 @@
>  #include <linux/spi/spi.h>
>  #include <linux/module.h>
>  #include <linux/of_platform.h>
> +#include <linux/version.h>
>
>  #include <mfd/rb4xx-cpld.h>
>
> @@ -151,9 +152,14 @@ static int rb4xx_cpld_probe(struct spi_device *spi)
>                                     NULL, 0, NULL);
>  }
>
> +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,18,0)
> +static void rb4xx_cpld_remove(struct spi_device *spi)
> +{
> +#else
>  static int rb4xx_cpld_remove(struct spi_device *spi)
>  {
>         return 0;
> +#endif

I'm pretty sure having a remove callback is optional, so why not just
delete it since it doesn't do anything anyway?

If we ever need one, we can just add one again.

Best Regards,
Jonas