diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 720cace3db4e..64872251e479 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h

@@ -273,6 +273,10 @@ struct mv88e6xxx_chip {
 	u16 trig_config;
 	u16 evcap_config;
 	u16 enable_count;
+	u32 ptp_cc_shift;
+	u32 ptp_cc_mult;
+	u32 ptp_cc_mult_num;
+	u32 ptp_cc_mult_dem;

 
 	/* Per-port timestamping resources. */
 	struct mv88e6xxx_port_hwtstamp port_hwtstamp[DSA_MAX_PORTS];

diff --git a/drivers/net/dsa/mv88e6xxx/ptp.c b/drivers/net/dsa/mv88e6xxx/ptp.c
index 768d256f7c9f..51cdf4712517 100644
--- a/drivers/net/dsa/mv88e6xxx/ptp.c
+++ b/drivers/net/dsa/mv88e6xxx/ptp.c

@@ -15,11 +15,38 @@
 #include "hwtstamp.h"
 #include "ptp.h"
 
-/* Raw timestamps are in units of 8-ns clock periods. */
-#define CC_SHIFT	28
-#define CC_MULT		(8 << CC_SHIFT)
-#define CC_MULT_NUM	(1 << 9)
-#define CC_MULT_DEM	15625ULL
+/* The adjfine API clamps ppb between [-32,768,000, 32,768,000], and
+ * therefore scaled_ppm between [-2,147,483,648, 2,147,483,647].
+ * Set the maximum supported ppb to a round value smaller than the maximum.
+ *
+ * Percentually speaking, this is a +/- 0.032x adjustment of the
+ * free-running counter (0.968x to 1.032x).
+ */
+#define MV88E6XXX_MAX_ADJ_PPB	32000000
+
+/* Family MV88E6250:
+ * Raw timestamps are in units of 10-ns clock periods.
+ *
+ * clkadj = scaled_ppm * 10*2^28 / (10^6 * 2^16)
+ * simplifies to
+ * clkadj = scaled_ppm * 2^7 / 5^5
+ */
+#define MV88E6250_CC_SHIFT	28
+#define MV88E6250_CC_MULT	(10 << MV88E6250_CC_SHIFT)
+#define MV88E6250_CC_MULT_NUM	(1 << 7)
+#define MV88E6250_CC_MULT_DEM	3125ULL
+
+/* Other families:
+ * Raw timestamps are in units of 8-ns clock periods.
+ *
+ * clkadj = scaled_ppm * 8*2^28 / (10^6 * 2^16)
+ * simplifies to
+ * clkadj = scaled_ppm * 2^9 / 5^6
+ */
+#define MV88E6XXX_CC_SHIFT	28
+#define MV88E6XXX_CC_MULT	(8 << MV88E6XXX_CC_SHIFT)
+#define MV88E6XXX_CC_MULT_NUM	(1 << 9)
+#define MV88E6XXX_CC_MULT_DEM	15625ULL