On Wed, 19 May 2021, at 15:44, Jiri Slaby wrote:
> On 19. 05. 21, 2:07, Andrew Jeffery wrote:
> > BIT(x) improves readability and safety with respect to shifts.
> >
> > Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
> > ---
> > drivers/tty/serial/8250/8250.h | 33 +++++++++++++++++----------------
> > 1 file changed, 17 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
> > index 34aa2714f3c9..4fbf1088fad8 100644
> > --- a/drivers/tty/serial/8250/8250.h
> > +++ b/drivers/tty/serial/8250/8250.h
> > @@ -7,6 +7,7 @@
> > * Copyright (C) 2001 Russell King.
> > */
> >
> > +#include <linux/bitops.h>
> > #include <linux/serial_8250.h>
> > #include <linux/serial_reg.h>
> > #include <linux/dmaengine.h>
> > @@ -70,25 +71,25 @@ struct serial8250_config {
> > unsigned int flags;
> > };
> >
> > -#define UART_CAP_FIFO (1 << 8) /* UART has FIFO */
> > -#define UART_CAP_EFR (1 << 9) /* UART has EFR */
> > -#define UART_CAP_SLEEP (1 << 10) /* UART has IER sleep */
> > -#define UART_CAP_AFE (1 << 11) /* MCR-based hw flow control */
> > -#define UART_CAP_UUE (1 << 12) /* UART needs IER bit 6 set (Xscale) */
> > -#define UART_CAP_RTOIE (1 << 13) /* UART needs IER bit 4 set (Xscale, Tegra) */
> > -#define UART_CAP_HFIFO (1 << 14) /* UART has a "hidden" FIFO */
> > -#define UART_CAP_RPM (1 << 15) /* Runtime PM is active while idle */
> > -#define UART_CAP_IRDA (1 << 16) /* UART supports IrDA line discipline */
> > -#define UART_CAP_MINI (1 << 17) /* Mini UART on BCM283X family lacks:
> > +#define UART_CAP_FIFO BIT(8) /* UART has FIFO */
> > +#define UART_CAP_EFR BIT(9) /* UART has EFR */
> > +#define UART_CAP_SLEEP BIT(10) /* UART has IER sleep */
>
>
> Perfect, except the include: BIT is not defined in bitops.h, but in
> bits.h (which includes vdso/bits.h). In fact, bitops.h includes bits.h
> too, but it's superfluous to include all those bitops.
Maybe the recommendation in the checkpatch documentation should be
fixed then?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/dev-tools/checkpatch.rst?h=v5.13-rc2#n473
I didn't dig through the include maze to optimise my choice.
That said, I will switch to bits.h based on your feedback above.
Thanks,
Andrew
