Re: [PATCH] spi: tegra20-slink: Declare runtime suspend and resume functions conditionally

[Thierry Reding]

On Mon, Sep 06, 2021 at 09:53:58PM -0700, Guenter Roeck wrote:
> The following build error is seen with CONFIG_PM=n.
> 
> drivers/spi/spi-tegra20-slink.c:1188:12: error:
> 	'tegra_slink_runtime_suspend' defined but not used
> drivers/spi/spi-tegra20-slink.c:1200:12: error:
> 	'tegra_slink_runtime_resume' defined but not used
> 
> Declare the functions only if PM is enabled. While at it, remove the
> unnecessary forward declarations.
> 
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
>  drivers/spi/spi-tegra20-slink.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/spi-tegra20-slink.c b/drivers/spi/spi-tegra20-slink.c
> index ebd27f883033..8ce840c7ecc8 100644
> --- a/drivers/spi/spi-tegra20-slink.c
> +++ b/drivers/spi/spi-tegra20-slink.c
> @@ -204,9 +204,6 @@ struct tegra_slink_data {
>  	struct dma_async_tx_descriptor		*tx_dma_desc;
>  };
>  
> -static int tegra_slink_runtime_suspend(struct device *dev);
> -static int tegra_slink_runtime_resume(struct device *dev);
> -
>  static inline u32 tegra_slink_readl(struct tegra_slink_data *tspi,
>  		unsigned long reg)
>  {
> @@ -1185,6 +1182,7 @@ static int tegra_slink_resume(struct device *dev)
>  }
>  #endif
>  
> +#ifdef CONFIG_PM
>  static int tegra_slink_runtime_suspend(struct device *dev)
>  {
>  	struct spi_master *master = dev_get_drvdata(dev);
> @@ -1210,6 +1208,7 @@ static int tegra_slink_runtime_resume(struct device *dev)
>  	}
>  	return 0;
>  }
> +#endif /* CONFIG_PM */
>  
>  static const struct dev_pm_ops slink_pm_ops = {
>  	SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,

Looks like this is mostly leftover from commit e4bb903fda0e ("spi:
tegra20-slink: Improve runtime PM usage"). That's likely going to go
into v5.15 since it's been in linux-next for a couple of weeks, so this
one should go there as well.

But yeah, looks correct. On a side-note: ARCH_TEGRA always selects PM,
so we typically assume that these guards are not needed. However, since
SPI's Kconfig has these two symbols || COMPILE_TEST, that assumption is
obviously no longer true.

Anyway, this looks correct, so:

Acked-by: Thierry Reding <treding@xxxxxxxxxx>

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