dm: i2c: Add a message debug function

Add a way to dump the contents of an I2C message for debugging purposes.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>

drivers/i2c/i2c-uclass.c

@@ -18,6 +18,22 @@ DECLARE_GLOBAL_DATA_PTR;
 
 #define I2C_MAX_OFFSET_LEN	4
 
+/* Useful debugging function */
+void i2c_dump_msgs(struct i2c_msg *msg, int nmsgs)
+{
+	int i;
+
+	for (i = 0; i < nmsgs; i++) {
+		struct i2c_msg *m = &msg[i];
+
+		printf("   %s %x len=%x", m->flags & I2C_M_RD ? "R" : "W",
+		       msg->addr, msg->len);
+		if (!(m->flags & I2C_M_RD))
+			printf(": %x", m->buf[0]);
+		printf("\n");
+	}
+}
+
 /**
  * i2c_setup_offset() - Set up a new message with a chip offset
  *

include/i2c.h

@@ -473,6 +473,16 @@ int i2c_get_chip_for_busnum(int busnum, int chip_addr, uint offset_len,
 int i2c_chip_ofdata_to_platdata(const void *blob, int node,
 				struct dm_i2c_chip *chip);
 
+/**
+ * i2c_dump_msgs() - Dump a list of I2C messages
+ *
+ * This may be useful for debugging.
+ *
+ * @msg:	Message list to dump
+ * @nmsgs:	Number of messages
+ */
+void i2c_dump_msgs(struct i2c_msg *msg, int nmsgs);
+
 #ifndef CONFIG_DM_I2C
 
 /*