while CONFIG_SND_DESIGNWARE_PCM is not set, building with W=1 shows this: sound/soc/dwc/local.h:127:6: warning: no previous prototype for ‘dw_pcm_push_tx’ [-Wmissing-prototypes] void dw_pcm_push_tx(struct dw_i2s_dev *dev) { } ^~~~~~~~~~~~~~ sound/soc/dwc/local.h:128:6: warning: no previous prototype for ‘dw_pcm_pop_rx’ [-Wmissing-prototypes] void dw_pcm_pop_rx(struct dw_i2s_dev *dev) { } ^~~~~~~~~~~~~ sound/soc/dwc/local.h:129:5: warning: no previous prototype for ‘dw_pcm_register’ [-Wmissing-prototypes] int dw_pcm_register(struct platform_device *pdev) ^~~~~~~~~~~~~~~ Change these to inline functions to fix the warnings. Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx> --- sound/soc/dwc/local.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sound/soc/dwc/local.h b/sound/soc/dwc/local.h index 91dc70a826f8..1c361eb6127e 100644 --- a/sound/soc/dwc/local.h +++ b/sound/soc/dwc/local.h @@ -124,9 +124,9 @@ void dw_pcm_push_tx(struct dw_i2s_dev *dev); void dw_pcm_pop_rx(struct dw_i2s_dev *dev); int dw_pcm_register(struct platform_device *pdev); #else -void dw_pcm_push_tx(struct dw_i2s_dev *dev) { } -void dw_pcm_pop_rx(struct dw_i2s_dev *dev) { } -int dw_pcm_register(struct platform_device *pdev) +static inline void dw_pcm_push_tx(struct dw_i2s_dev *dev) { } +static inline void dw_pcm_pop_rx(struct dw_i2s_dev *dev) { } +static inline int dw_pcm_register(struct platform_device *pdev) { return -EINVAL; } -- 2.17.1