can: rcar_canfd: Simplify clock handling

The main CAN clock is either the internal CANFD clock, or the external
CAN clock.  Hence replace the two-valued enum by a simple boolean flag.
Consolidate all CANFD clock handling inside a single branch.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/2cf38c10b83c8e5c04d68b17a930b6d9dbf66f40.1716973640.git.geert+renesas@glider.be
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/rcar/rcar_canfd.c

@@ -508,12 +508,6 @@
  */
 #define RCANFD_CFFIFO_IDX		0
 
-/* fCAN clock select register settings */
-enum rcar_canfd_fcanclk {
-	RCANFD_CANFDCLK = 0,		/* CANFD clock */
-	RCANFD_EXTCLK,			/* Externally input clock */
-};
-
 struct rcar_canfd_global;
 
 struct rcar_canfd_hw_info {
@@ -545,8 +539,8 @@ struct rcar_canfd_global {
 	struct platform_device *pdev;	/* Respective platform device */
 	struct clk *clkp;		/* Peripheral clock */
 	struct clk *can_clk;		/* fCAN clock */
-	enum rcar_canfd_fcanclk fcan;	/* CANFD or Ext clock */
 	unsigned long channels_mask;	/* Enabled channels mask */
+	bool extclk;			/* CANFD or Ext clock */
 	bool fdmode;			/* CAN FD or Classical CAN only mode */
 	struct reset_control *rstc1;
 	struct reset_control *rstc2;
@@ -777,7 +771,7 @@ static void rcar_canfd_configure_controller(struct rcar_canfd_global *gpriv)
 		cfg |= RCANFD_GCFG_CMPOC;
 
 	/* Set External Clock if selected */
-	if (gpriv->fcan != RCANFD_CANFDCLK)
+	if (gpriv->extclk)
 		cfg |= RCANFD_GCFG_DCS;
 
 	rcar_canfd_set_bit(gpriv->base, RCANFD_GCFG, cfg);
@@ -1941,16 +1935,12 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 			return dev_err_probe(dev, PTR_ERR(gpriv->can_clk),
 					     "cannot get canfd clock\n");
 
-		gpriv->fcan = RCANFD_CANFDCLK;
-
+		/* CANFD clock may be further divided within the IP */
+		fcan_freq = clk_get_rate(gpriv->can_clk) / info->postdiv;
 	} else {
-		gpriv->fcan = RCANFD_EXTCLK;
+		fcan_freq = clk_get_rate(gpriv->can_clk);
+		gpriv->extclk = true;
 	}
-	fcan_freq = clk_get_rate(gpriv->can_clk);
-
-	if (gpriv->fcan == RCANFD_CANFDCLK)
-		/* CANFD clock is further divided by (1/2) within the IP */
-		fcan_freq /= info->postdiv;
 
 	addr = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(addr)) {
@@ -2060,7 +2050,7 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, gpriv);
 	dev_info(dev, "global operational state (clk %d, fdmode %d)\n",
-		 gpriv->fcan, gpriv->fdmode);
+		 gpriv->extclk, gpriv->fdmode);
 	return 0;
 
 fail_channel: