Re: [PATCH v2] usb: musb: remove unused variable 'devctl'
From: Greg Kroah-Hartman
Date: Tue Nov 24 2020 - 02:23:52 EST
On Tue, Nov 24, 2020 at 02:36:13PM +0800, min.guo@xxxxxxxxxxxx wrote:
> From: Min Guo <min.guo@xxxxxxxxxxxx>
>
> Remove unused 'devctl' variable to fix compile warnings:
>
> drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> but not used [-Wunused-but-set-variable]
>
> Signed-off-by: Min Guo <min.guo@xxxxxxxxxxxx>
> ---
> changes in v2
> suggested by Alan Stern:
> Add void before musb_read to indicate that the register MUSB_DEVCTL
> was intended to be read and discarded.
> ---
> drivers/usb/musb/musbhsdma.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> index 0aacfc8be5a1..f59a009c533e 100644
> --- a/drivers/usb/musb/musbhsdma.c
> +++ b/drivers/usb/musb/musbhsdma.c
> @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> musb_channel->channel.status =
> MUSB_DMA_STATUS_BUS_ABORT;
> } else {
> - u8 devctl;
> -
> addr = musb_read_hsdma_addr(mbase,
> bchannel);
> channel->actual_len = addr
> @@ -336,7 +334,7 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> < musb_channel->len) ?
> "=> reconfig 0" : "=> complete");
>
> - devctl = musb_readb(mbase, MUSB_DEVCTL);
> + (void)musb_readb(mbase, MUSB_DEVCTL);
Please put a comment here as to why the read is happening so that people
do not throw it away sometime in the future.
thanks,
greg k-h