serial: sh-sci: Make unsigned values in sci_baud_calc_hscif() unsigned

Move the -1 offset of br to the assignment to *brr, so br cannot become
negative anymore, and update the clamp() call. Now all unsigned values
in sci_baud_calc_hscif() can become unsigned.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sh-sci.c

@@ -1870,7 +1870,8 @@ static unsigned int sci_scbrr_calc(struct sci_port *s, unsigned int bps,
 static void sci_baud_calc_hscif(unsigned int bps, unsigned long freq, int *brr,
 				unsigned int *srr, unsigned int *cks)
 {
-	int sr, c, br, err, recv_margin;
+	unsigned int sr, br, c;
+	int err, recv_margin;
 	int min_err = 1000; /* 100% */
 	int recv_max_margin = 0;
 
@@ -1880,9 +1881,9 @@ static void sci_baud_calc_hscif(unsigned int bps, unsigned long freq, int *brr,
 		for (c = 0; c <= 3; c++) {
 			/* integerized formulas from HSCIF documentation */
 			br = DIV_ROUND_CLOSEST(freq, (sr *
-					      (1 << (2 * c + 1)) * bps)) - 1;
-			br = clamp(br, 0, 255);
-			err = DIV_ROUND_CLOSEST(freq, ((br + 1) * bps * sr *
+					      (1 << (2 * c + 1)) * bps));
+			br = clamp(br, 1U, 256U);
+			err = DIV_ROUND_CLOSEST(freq, (br * bps * sr *
 					       (1 << (2 * c + 1)) / 1000)) -
 					       1000;
 			/* Calc recv margin
@@ -1908,7 +1909,7 @@ static void sci_baud_calc_hscif(unsigned int bps, unsigned long freq, int *brr,
 			else
 				continue;
 
-			*brr = br;
+			*brr = br - 1;
 			*srr = sr - 1;
 			*cks = c;
 		}