linux-kernel - [PATCH 1/3] hwrng: imx-rngc - use bitfield macros to read fifo level

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Date:   Thu, 27 Apr 2023 20:53:55 +0200
From:   Martin Kaiser <martin@...ser.cx>
To:     Herbert Xu <herbert@...dor.apana.org.au>
Cc:     linux-crypto@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Martin Kaiser <martin@...ser.cx>
Subject: [PATCH 1/3] hwrng: imx-rngc - use bitfield macros to read fifo level

Use the mechanism from bitfield.h to read the fifo level field in the
status register. This makes the code a tiny bit simpler.

Signed-off-by: Martin Kaiser <martin@...ser.cx>
---
 drivers/char/hw_random/imx-rngc.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index a1c24148ed31..861a615ac7df 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -17,6 +17,7 @@
 #include <linux/hw_random.h>
 #include <linux/completion.h>
 #include <linux/io.h>
+#include <linux/bitfield.h>
 
 #define RNGC_VER_ID			0x0000
 #define RNGC_COMMAND			0x0004
@@ -44,8 +45,7 @@
 #define RNGC_CTRL_AUTO_SEED		0x00000010
 
 #define RNGC_STATUS_ERROR		0x00010000
-#define RNGC_STATUS_FIFO_LEVEL_MASK	0x00000f00
-#define RNGC_STATUS_FIFO_LEVEL_SHIFT	8
+#define RNGC_STATUS_FIFO_LEVEL		GENMASK(11, 8)
 #define RNGC_STATUS_SEED_DONE		0x00000020
 #define RNGC_STATUS_ST_DONE		0x00000010
 
@@ -133,9 +133,7 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait)
 			break;
 
 		/* how many random numbers are in FIFO? [0-16] */
-		level = (status & RNGC_STATUS_FIFO_LEVEL_MASK) >>
-			RNGC_STATUS_FIFO_LEVEL_SHIFT;
-
+		level = FIELD_GET(RNGC_STATUS_FIFO_LEVEL, status);
 		if (level) {
 			/* retrieve a random number from FIFO */
 			*(u32 *)data = readl(rngc->base + RNGC_FIFO);
-- 
2.30.2