Re: [PATCH -next] staging: comedi: Remove unused variable ‘min_full_scale’

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, May 13, 2021 at 09:34:58PM +0800, Bixuan Cui wrote:
> Fix the following build warnings:
> drivers/comedi/drivers/jr3_pci.c:507:22:
> 	warning: variable ‘min_full_scale’ set but not used
> 
> And fix build warnings after removing ‘min_full_scale’:
> drivers/comedi/drivers/jr3_pci.c:189:26:
> 	warning: ‘get_min_full_scales’ defined but not used
>  static struct six_axis_t get_min_full_scales(struct jr3_sensor __iomem *sensor)
>                           ^~~~~~~~~~~~~~~~~~~
> 
> Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
> ---
>  drivers/comedi/drivers/jr3_pci.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/comedi/drivers/jr3_pci.c b/drivers/comedi/drivers/jr3_pci.c
> index 7a02c4fa3cda..122b95dc2bf9 100644
> --- a/drivers/comedi/drivers/jr3_pci.c
> +++ b/drivers/comedi/drivers/jr3_pci.c
> @@ -186,7 +186,7 @@ static void set_full_scales(struct jr3_sensor __iomem *sensor,
>  	set_s16(&sensor->command_word0, 0x0a00);
>  }
>  
> -static struct six_axis_t get_min_full_scales(struct jr3_sensor __iomem *sensor)
> +static __maybe_unused struct six_axis_t get_min_full_scales(struct jr3_sensor __iomem *sensor)

If it really is not used, then remove it, don't paper over a compiler
warning for no good reason please.

Fix this properly.

>  {
>  	struct six_axis_t result;
>  
> @@ -504,10 +504,8 @@ jr3_pci_poll_subdevice(struct comedi_subdevice *s)
>  			result = poll_delay_min_max(20, 100);
>  		} else {
>  			/* Set full scale */
> -			struct six_axis_t min_full_scale;
>  			struct six_axis_t max_full_scale;
>  
> -			min_full_scale = get_min_full_scales(sensor);
>  			max_full_scale = get_max_full_scales(sensor);

Did you just break the driver by messing with the order of reading from
the device?

thanks,

greg k-h