rockchip: spi: Remember the last speed to avoid re-setting it

Rather than changing the clock to the same value on every transaction,
remember the last value and don't adjust the clock unless it is necessary.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/spi/rk_spi.c b/drivers/spi/rk_spi.c
index 2b58393e35700769014ef50a0aa7ac9f976eb69e..aaf139d823ede144673001005a2429eb6eb5da05 100644 (file)
--- a/drivers/spi/rk_spi.c
+++ b/drivers/spi/rk_spi.c
@@ -44,6 +44,7 @@ struct rockchip_spi_priv {
        u8 bits_per_word;               /* max 16 bits per word */
        u8 n_bytes;
        unsigned int speed_hz;
+       unsigned int last_speed_hz;
        unsigned int tmode;
        uint input_rate;
 };
@@ -82,6 +83,7 @@ static void rkspi_set_clk(struct rockchip_spi_priv *priv, uint speed)
        debug("spi speed %u, div %u\n", speed, clk_div);
 
        writel(clk_div, &priv->regs->baudr);
+       priv->last_speed_hz = speed;
 }
 
 static int rkspi_wait_till_not_busy(struct rockchip_spi *regs)
@@ -212,7 +214,8 @@ static int rockchip_spi_claim_bus(struct udevice *dev)
                return -EPROTONOSUPPORT;
        }
 
-       rkspi_set_clk(priv, priv->speed_hz);
+       if (priv->speed_hz != priv->last_speed_hz)
+               rkspi_set_clk(priv, priv->speed_hz);
 
        /* Operation Mode */
        ctrlr0 = OMOD_MASTER << OMOD_SHIFT;