kw_spi: fix clock prescaler computation

[platform/kernel/u-boot.git] / drivers / spi / kirkwood_spi.c

diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c
index f4523a3..a7cda75 100644 (file)
--- a/drivers/spi/kirkwood_spi.c
+++ b/drivers/spi/kirkwood_spi.c
@@ -56,8 +56,9 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
        writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
 
        /* calculate spi clock prescaller using max_hz */
-       data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK;
-       data |= 0x10;
+       data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10;
+       data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data;
+       data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data;
 
        /* program spi clock prescaller using max_hz */
        writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);