[U-Boot] [PATCH 40/50] rockchip: spi: Remember the last speed to avoid re-setting it

Simon Glass
2016-01-13T23:25:30Z

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>
---

drivers/spi/rk_spi.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/rk_spi.c b/drivers/spi/rk_spi.c
index f98284c..7b4a04c 100644
--- 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)
@@ -211,7 +213,8 @@ 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;
--
2.6.0.rc2.230.g3dd15c0