On 19. 05. 21, 8:27, Andrew Jeffery wrote:

On Wed, 19 May 2021, at 15:44, Jiri Slaby wrote:

quoted

On 19. 05. 21, 2:07, Andrew Jeffery wrote:

quoted

BIT(x) improves readability and safety with respect to shifts.

Signed-off-by: Andrew Jeffery <redacted>
---
   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?

+1 since:

commit 8bd9cb51daac89337295b6f037b0486911e1b408
Author: Will Deacon [off-list ref]
Date:   Tue Jun 19 13:53:08 2018 +0100

     locking/atomics, asm-generic: Move some macros from 
<linux/bitops.h> to a new <linux/bits.h> file

So care to fix checkpatch too :)?

thanks,
-- 
js
suse labs