spi: kirkwood: prevent configuring speed exceeding max controller freq

This patch adds a limitation in the kirkwood_spi driver
set_speed hook, which prevents setting too high transfer
speed.

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Kostya Porotchkin <kostap@marvell.com>
Tested-by: Kostya Porotchkin <kostap@marvell.com>
Signed-off-by: Stefan Roese <sr@denx.de>

diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c
index 3dc62f351a06617eefbe8d56a7caf7cbee4469bf..063ed5f35a3a06cda0a6aa5516583af598f508cf 100644 (file)
--- a/drivers/spi/kirkwood_spi.c
+++ b/drivers/spi/kirkwood_spi.c
@@ -110,10 +110,17 @@ static int _spi_xfer(struct kwspi_registers *reg, unsigned int bitlen,
 static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
 {
        struct mvebu_spi_plat *plat = dev_get_plat(bus);
+       struct dm_spi_bus *spi = dev_get_uclass_priv(bus);
        struct kwspi_registers *reg = plat->spireg;
        u32 data, divider;
        unsigned int spr, sppr;
 
+       if (hz > spi->max_hz) {
+               debug("%s: limit speed to the max_hz of the bus %d\n",
+                     __func__, spi->max_hz);
+               hz = spi->max_hz;
+       }
+
        /*
         * Calculate spi clock prescaller using max_hz.
         * SPPR is SPI Baud Rate Pre-selection, it holds bits 5 and 7:6 in