clk: renesas: rcar-gen4: Use FIELD_GET()

Improve readability by using the FIELD_GET() helper instead of
open-coding the same operation, and by adding field definitions to get
rid of hardcoded values.

While at it, move register definitions that are only used inside the
rcar-gen4-cpg.c source file out of the rcar-gen4-cpg.h header file.
Add a "CPG_" prefix to SD0CKCR1.  Add comments where appropriate.

Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Yoshihiro Shimoda <[email protected]>
Link: https://lore.kernel.org/fb19ad829738f02effa340fa04c178a162d41202.1721648548.git.geert+renesas@glider.be

Author: geertu

drivers/clk/renesas/rcar-gen4-cpg.c

@@ -55,6 +55,14 @@ static u32 cpg_mode __initdata;
 /* Fractional 8.25 PLL */
 #define CPG_PLLxCR0_NI8		GENMASK(27, 20)	/* Integer mult. factor */
 
+#define CPG_PLLxCR_STC		GENMASK(30, 24)	/* R_Car V3U PLLxCR */
+
+#define CPG_RPCCKCR		0x874	/* RPC Clock Freq. Control Register */
+
+#define CPG_SD0CKCR1		0x8a4	/* SD-IF0 Clock Freq. Control Reg. 1 */
+
+#define CPG_SD0CKCR1_SDSRC_SEL	GENMASK(30, 29)	/* SDSRC clock freq. select */
+
 /* PLL Clocks */
 struct cpg_pll_clk {
 	struct clk_hw hw;
@@ -392,15 +400,16 @@ struct clk * __init rcar_gen4_cpg_clk_register(struct device *dev,
 
 	case CLK_TYPE_GEN4_PLL2X_3X:
 		value = readl(base + core->offset);
-		mult = (((value >> 24) & 0x7f) + 1) * 2;
+		mult = (FIELD_GET(CPG_PLLxCR_STC, value) + 1) * 2;
 		break;
 
 	case CLK_TYPE_GEN4_Z:
 		return cpg_z_clk_register(core->name, __clk_get_name(parent),
 					  base, core->div, core->offset);
 
 	case CLK_TYPE_GEN4_SDSRC:
-		div = ((readl(base + SD0CKCR1) >> 29) & 0x03) + 4;
+		value = readl(base + CPG_SD0CKCR1);
+		div = FIELD_GET(CPG_SD0CKCR1_SDSRC_SEL, value) + 4;
 		break;
 
 	case CLK_TYPE_GEN4_SDH:

drivers/clk/renesas/rcar-gen4-cpg.h

@@ -67,9 +67,6 @@ struct rcar_gen4_cpg_pll_config {
 	u8 osc_prediv;
 };
 
-#define CPG_RPCCKCR	0x874
-#define SD0CKCR1	0x8a4
-
 struct clk *rcar_gen4_cpg_clk_register(struct device *dev,
 	const struct cpg_core_clk *core, const struct cpg_mssr_info *info,
 	struct clk **clks, void __iomem *base,