userspace/libwr: function to enable/disable PPS-in termination

Requires gateware synthesized with wr-switch-hdl commit:
b1b621b add bit to control WRS 1-PPS in termination

kernel/wbgen-regs/ppsg-regs.h

@@ -84,6 +84,9 @@
 /* definitions for field: Set nanoseconds counter in reg: External sync control register */
 #define PPSG_ESCR_NSEC_SET                    WBGEN2_GEN_MASK(4, 1)
 
+/* definitions for field: Enable PPS_IN 50Ohm termination in reg: External sync control register */
+#define PPSG_ESCR_PPS_IN_TERM                 WBGEN2_GEN_MASK(5, 1)
+
 PACKED struct PPSG_WB {
   /* [0x0]: REG Control Register */
   uint32_t CR;

kernel/wbgen-regs/ppsg-regs.wb

@@ -210,6 +210,18 @@ peripheral {
          clock = "refclk_i";
 			};
 
+      field {
+        name = "Enable PPS_IN 50Ohm termination";
+        description = "write 1: enable 50ohm termination for 1-PPS input \
+                       write 0: disable 50ohm termination for 1-PPS input \
+                       read  1: 50ohm termination for 1-PPS input enabled \
+                       read  0: 50ohm termination for 1-PPS input disabled";
+        prefix = "PPS_IN_TERM";
+        type = BIT;
+        access_bus = READ_WRITE;
+        access_dev = READ_ONLY;
+      };
+
 	 };
 
 };

userspace/libwr/pps_gen.c

@@ -105,3 +105,12 @@ void shw_pps_gen_read_time(uint64_t * seconds, uint32_t * nanoseconds)
 	if (nanoseconds)
 		*nanoseconds = ns_cnt;
 }
+
+void shw_pps_gen_in_term_enable(int enable)
+{
+	uint32_t escr = ppsg_read(ESCR);
+	if (enable)
+		ppsg_write(ESCR, escr | PPSG_ESCR_PPS_IN_TERM);
+	else
+		ppsg_write(ESCR, escr & ~PPSG_ESCR_PPS_IN_TERM);
+}