can: rcar_canfd: Update RCANFD_CFG_* macros

Update RCANFD_CFG_* macros to give a meaning to the magic number using
GENMASK macro and extract the values using FIELD_PREP macro.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20250908120940.147196-3-biju.das.jz@bp.renesas.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Author: bijudas

drivers/net/can/rcar/rcar_canfd.c

@@ -103,10 +103,10 @@
 /* Channel register bits */
 
 /* RSCFDnCmCFG - Classical CAN only */
-#define RCANFD_CFG_SJW(x)		(((x) & 0x3) << 24)
-#define RCANFD_CFG_TSEG2(x)		(((x) & 0x7) << 20)
-#define RCANFD_CFG_TSEG1(x)		(((x) & 0xf) << 16)
-#define RCANFD_CFG_BRP(x)		(((x) & 0x3ff) << 0)
+#define RCANFD_CFG_SJW		GENMASK(25, 24)
+#define RCANFD_CFG_TSEG2	GENMASK(22, 20)
+#define RCANFD_CFG_TSEG1	GENMASK(19, 16)
+#define RCANFD_CFG_BRP		GENMASK(9, 0)
 
 /* RSCFDnCFDCmNCFG - CAN FD only */
 #define RCANFD_NCFG_NTSEG2(gpriv, x) \
@@ -1411,8 +1411,8 @@ static void rcar_canfd_set_bittiming(struct net_device *ndev)
 		cfg = (RCANFD_NCFG_NTSEG1(gpriv, tseg1) | RCANFD_NCFG_NBRP(brp) |
 		       RCANFD_NCFG_NSJW(gpriv, sjw) | RCANFD_NCFG_NTSEG2(gpriv, tseg2));
 	} else {
-		cfg = (RCANFD_CFG_TSEG1(tseg1) | RCANFD_CFG_BRP(brp) |
-		       RCANFD_CFG_SJW(sjw) | RCANFD_CFG_TSEG2(tseg2));
+		cfg = FIELD_PREP(RCANFD_CFG_TSEG1, tseg1) | FIELD_PREP(RCANFD_CFG_BRP, brp) |
+		      FIELD_PREP(RCANFD_CFG_SJW, sjw) | FIELD_PREP(RCANFD_CFG_TSEG2, tseg2);
 	}
 
 	rcar_canfd_write(priv->base, RCANFD_CCFG(ch), cfg);