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staging: media: tegra-video: use BIT() macro instead of shift

PATCH In review A.T. Jefferies 2 participants 2 messages Jul 24, 2025 – Jul 25, 2025

Subsystems (4)
Media (V4L/DVB) Staging Tegra architecture support Tegra video driver
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A.T. Jefferies

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#0 lore raw

PATCH 1/1 staging: media: tegra-video: use BIT() macro instead of shift

Replace two instances of (1 << X) with BIT(X) in tegra20.c to follow kernel coding style guidelines and improve clarity. The BIT() macro also ensures proper type handling for larger shifts.

Signed-off-by A.T. Jefferies <[email protected]>
---
 drivers/staging/media/tegra-video/tegra20.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/staging/media/tegra-video/tegra20.c +2 -2
index 7b8f8f810b35..1473f1b1f203 100644
@@ -42,7 +42,7 @@
 #define       VI_INPUT_BT656				BIT(25)
 #define       VI_INPUT_YUV_INPUT_FORMAT_SFT		8  /* bits [9:8] */
 #define       VI_INPUT_YUV_INPUT_FORMAT_UYVY		(0 << VI_INPUT_YUV_INPUT_FORMAT_SFT)
-#define       VI_INPUT_YUV_INPUT_FORMAT_VYUY		(1 << VI_INPUT_YUV_INPUT_FORMAT_SFT)
+#define       VI_INPUT_YUV_INPUT_FORMAT_VYUY		BIT(VI_INPUT_YUV_INPUT_FORMAT_SFT)
 #define       VI_INPUT_YUV_INPUT_FORMAT_YUYV		(2 << VI_INPUT_YUV_INPUT_FORMAT_SFT)
 #define       VI_INPUT_YUV_INPUT_FORMAT_YVYU		(3 << VI_INPUT_YUV_INPUT_FORMAT_SFT)
 #define       VI_INPUT_INPUT_FORMAT_SFT			2  /* bits [5:2] */

@@ -73,7 +73,7 @@
 #define       VI_OUTPUT_H_DIRECTION			BIT(19)
 #define       VI_OUTPUT_YUV_OUTPUT_FORMAT_SFT		17
 #define       VI_OUTPUT_YUV_OUTPUT_FORMAT_UYVY		(0 << VI_OUTPUT_YUV_OUTPUT_FORMAT_SFT)
-#define       VI_OUTPUT_YUV_OUTPUT_FORMAT_VYUY		(1 << VI_OUTPUT_YUV_OUTPUT_FORMAT_SFT)
+#define       VI_OUTPUT_YUV_OUTPUT_FORMAT_VYUY		BIT(VI_OUTPUT_YUV_OUTPUT_FORMAT_SFT)
 #define       VI_OUTPUT_YUV_OUTPUT_FORMAT_YUYV		(2 << VI_OUTPUT_YUV_OUTPUT_FORMAT_SFT)
 #define       VI_OUTPUT_YUV_OUTPUT_FORMAT_YVYU		(3 << VI_OUTPUT_YUV_OUTPUT_FORMAT_SFT)
 #define       VI_OUTPUT_OUTPUT_BYTE_SWAP		BIT(16)
Signature · 1 line
2.50.0
maintainer
#1 lore raw

Hello A.T. Jefferies,

Quoted 14 lines · On Wed, 23 Jul 2025 23:17:57 +0000 "A.T. Jefferies" <[email protected]>…

Replace two instances of (1 << X) with BIT(X) in tegra20.c to follow kernel coding style guidelines and improve clarity. The BIT() macro also ensures proper type handling for larger shifts.

Signed-off-by A.T. Jefferies <[email protected]>
---
 drivers/staging/media/tegra-video/tegra20.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/staging/media/tegra-video/tegra20.c +0 -0
index 7b8f8f810b35..1473f1b1f203 100644

drivers/staging/media/tegra-video/tegra20.c line 47

Quoted 7 lines
drivers/staging/media/tegra-video/tegra20.c +1 -1
@@ -42,7 +42,7 @@
 #define       VI_INPUT_BT656				BIT(25)
 #define       VI_INPUT_YUV_INPUT_FORMAT_SFT		8  /* bits [9:8] */
 #define       VI_INPUT_YUV_INPUT_FORMAT_UYVY		(0 << VI_INPUT_YUV_INPUT_FORMAT_SFT)
-#define       VI_INPUT_YUV_INPUT_FORMAT_VYUY		(1 << VI_INPUT_YUV_INPUT_FORMAT_SFT)
+#define       VI_INPUT_YUV_INPUT_FORMAT_VYUY		BIT(VI_INPUT_YUV_INPUT_FORMAT_SFT)
 #define       VI_INPUT_YUV_INPUT_FORMAT_YUYV		(2 << VI_INPUT_YUV_INPUT_FORMAT_SFT)
 #define       VI_INPUT_YUV_INPUT_FORMAT_YVYU		(3 << VI_INPUT_YUV_INPUT_FORMAT_SFT)

Thanks for your patch. However I'm afraid I don't think this is a good idea. 1 is just one out of 4 possible values out of 4 possible values for a multi-bit register field. All the 4 should use the same style.

BIT() is perfect for single-bit register fields. It's not for multi-bit fields.

Luca

Signature · 3 lines
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com