i2c: spacemit: move i2c_xfer_msg()

The upcoming PIO support requires a wait_pio_xfer() helper, which is
invoked from xfer_msg().

Since wait_pio_xfer() depends on err_check(), move the definition of
xfer_msg() after err_check() to avoid a forward declaration of
err_check().

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Alex Elder <elder@riscstar.com>
Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260207-b4-k3-i2c-pio-v7-1-626942d94d91@linux.spacemit.com

Author: TroyMitchell911

drivers/i2c/busses/i2c-k1.c

@@ -305,37 +305,6 @@ static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c)
 	writel(val, i2c->base + SPACEMIT_ICR);
 }
 
-static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c)
-{
-	unsigned long time_left;
-	struct i2c_msg *msg;
-
-	for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) {
-		msg = &i2c->msgs[i2c->msg_idx];
-		i2c->msg_buf = msg->buf;
-		i2c->unprocessed = msg->len;
-		i2c->status = 0;
-
-		reinit_completion(&i2c->complete);
-
-		spacemit_i2c_start(i2c);
-
-		time_left = wait_for_completion_timeout(&i2c->complete,
-							i2c->adapt.timeout);
-		if (!time_left) {
-			dev_err(i2c->dev, "msg completion timeout\n");
-			spacemit_i2c_conditionally_reset_bus(i2c);
-			spacemit_i2c_reset(i2c);
-			return -ETIMEDOUT;
-		}
-
-		if (i2c->status & SPACEMIT_SR_ERR)
-			return spacemit_i2c_handle_err(i2c);
-	}
-
-	return 0;
-}
-
 static bool spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c)
 {
 	if (i2c->msg_idx != i2c->msg_num - 1)
@@ -419,6 +388,37 @@ static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c)
 	complete(&i2c->complete);
 }
 
+static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c)
+{
+	unsigned long time_left;
+	struct i2c_msg *msg;
+
+	for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) {
+		msg = &i2c->msgs[i2c->msg_idx];
+		i2c->msg_buf = msg->buf;
+		i2c->unprocessed = msg->len;
+		i2c->status = 0;
+
+		reinit_completion(&i2c->complete);
+
+		spacemit_i2c_start(i2c);
+
+		time_left = wait_for_completion_timeout(&i2c->complete,
+							i2c->adapt.timeout);
+		if (!time_left) {
+			dev_err(i2c->dev, "msg completion timeout\n");
+			spacemit_i2c_conditionally_reset_bus(i2c);
+			spacemit_i2c_reset(i2c);
+			return -ETIMEDOUT;
+		}
+
+		if (i2c->status & SPACEMIT_SR_ERR)
+			return spacemit_i2c_handle_err(i2c);
+	}
+
+	return 0;
+}
+
 static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid)
 {
 	struct spacemit_i2c_dev *i2c = devid;