spi: fsl-dspi: Fix clock rate scale values

[cascardo/linux.git] / drivers / spi / spi-fsl-dspi.c

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index d1a3924..96cac87 100644 (file)
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -148,23 +148,30 @@ static void hz_to_spi_baud(char *pbr, char *br, int speed_hz,
                16,     32,     64,     128,
                256,    512,    1024,   2048,
                4096,   8192,   16384,  32768 };
-       int temp, i = 0, j = 0;
-
-       temp = clkrate / 2 / speed_hz;
-
-       for (i = 0; i < ARRAY_SIZE(pbr_tbl); i++)
-               for (j = 0; j < ARRAY_SIZE(brs); j++) {
-                       if (pbr_tbl[i] * brs[j] >= temp) {
-                               *pbr = i;
-                               *br = j;
-                               return;
+       int scale_needed, scale, minscale = INT_MAX;
+       int i, j;
+
+       scale_needed = clkrate / speed_hz;
+
+       for (i = 0; i < ARRAY_SIZE(brs); i++)
+               for (j = 0; j < ARRAY_SIZE(pbr_tbl); j++) {
+                       scale = brs[i] * pbr_tbl[j];
+                       if (scale >= scale_needed) {
+                               if (scale < minscale) {
+                                       minscale = scale;
+                                       *br = i;
+                                       *pbr = j;
+                               }
+                               break;
                        }
                }
 
-       pr_warn("Can not find valid baud rate,speed_hz is %d,clkrate is %ld\
-               ,we use the max prescaler value.\n", speed_hz, clkrate);
-       *pbr = ARRAY_SIZE(pbr_tbl) - 1;
-       *br =  ARRAY_SIZE(brs) - 1;
+       if (minscale == INT_MAX) {
+               pr_warn("Can not find valid baud rate,speed_hz is %d,clkrate is %ld, we use the max prescaler value.\n",
+                       speed_hz, clkrate);
+               *pbr = ARRAY_SIZE(pbr_tbl) - 1;
+               *br =  ARRAY_SIZE(brs) - 1;
+       }
 }
 
 static int dspi_transfer_write(struct fsl_dspi *dspi)