power: replace magic numbers with macros

Replace magic numbers in buckval2votl() & buckvolt2val() with macros to
help with clarity and correlate what the numbers correspond to in the
TPS65219 datasheet.

Signed-off-by: Shree Ramamoorthy <s-ramamoorthy@ti.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/include/power/tps65219.h b/include/power/tps65219.h
index aa81b92..e8780af 100644
--- a/include/power/tps65219.h
+++ b/include/power/tps65219.h
@@ -17,10 +17,20 @@
 #define TPS65219_BUCK_DRIVER		"tps65219_buck"
 
 #define TPS65219_VOLT_MASK		0x3F
-#define TPS65219_BUCK_VOLT_MAX		3400000
-
 #define TPS65219_ENABLE_CTRL_REG	0x2
 
+#define TPS65219_VOLT_STEP_25MV		25000
+#define TPS65219_VOLT_STEP_50MV		50000
+#define TPS65219_VOLT_STEP_100MV	100000
+
+#define TPS65219_BUCK_0V6		600000
+#define TPS65219_BUCK_1V4		1400000
+#define TPS65219_BUCK_3V4		3400000
+
+#define TPS65219_BUCK_REG_0V6		0x00
+#define TPS65219_BUCK_REG_1V4		0x20
+#define TPS65219_BUCK_REG_3V4		0x34
+
 #define TPS65219_BUCK1_VOUT_REG		0xa
 #define TPS65219_BUCK2_VOUT_REG		0x9
 #define TPS65219_BUCK3_VOUT_REG		0x8