1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 818843336932..a816f07e168e 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -295,14 +295,24 @@ static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
 static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size)
 {
         int spbr;
+        int div = 0;
+        unsigned long clksrc;
 
         /* Sets output mode, MOSI signal, and (optionally) loopback */
         rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
+        clksrc = clk_get_rate(rspi->clk);
+        while (div < 3) {
+                if (rspi->max_speed_hz >= clksrc/4) /* 4=(CLK/2)/2 */
+                        break;
+                div++;
+                clksrc /= 2;
+        }
+
         /* Sets transfer bit rate */
-        spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk),
-                            2 * rspi->max_speed_hz) - 1;
+        spbr = DIV_ROUND_UP(clksrc, 2 * rspi->max_speed_hz) - 1;
         rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
+        rspi->spcmd |= div << 2;
 
         /* Disable dummy transmission, set byte access */
         rspi_write8(rspi, SPDCR_SPLBYTE, RSPI_SPDCR);