On Mon, 2017-03-27 at 22:12 -0700, Brendan Higgins wrote:

+/* 0x04 : I2CD Clock and AC Timing Control Register #1 */
+#define ASPEED_I2CD_TIME_SCL_HIGH_SHIFT                        16
+#define ASPEED_I2CD_TIME_SCL_HIGH_MASK                 GENMASK(19, 16)
+#define ASPEED_I2CD_TIME_SCL_LOW_SHIFT                 12
+#define ASPEED_I2CD_TIME_SCL_LOW_MASK                  GENMASK(15, 12)
+#define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK             GENMASK(3, 0)
+#define ASPEED_I2CD_TIME_SCL_REG_MAX                   GENMASK(3, 0)
+/* 0x08 : I2CD Clock and AC Timing Control Register #2 */
+#define ASPEED_NO_TIMEOUT_CTRL                         0

Those are slightly different between the 2400 and 2500, allowing
slightly more fine grained settings (faster base clock and thus higher
numbers in high/low counts).

I *think* that using the 2400 values as-is might work ok, at least
it does for 100kHz but I would double check.

I'll review the rest tomorrow.

Cheers,
Ben.