spi: fsl-espi: don't write ESPI_SPMODE register if the mode doesn't change
There's no need to bother the chip if the mode doesn't change.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index 1029bd2..edb524f 100644
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -249,6 +249,7 @@
int bits_per_word = t ? t->bits_per_word : spi->bits_per_word;
u32 pm, hz = t ? t->speed_hz : spi->max_speed_hz;
struct spi_mpc8xxx_cs *cs = spi->controller_state;
+ u32 hw_mode_old = cs->hw_mode;
/* mask out bits we are going to set */
cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF));
@@ -271,8 +272,10 @@
cs->hw_mode |= CSMODE_PM(pm);
- fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPMODEx(spi->chip_select),
- cs->hw_mode);
+ /* don't write the mode register if the mode doesn't change */
+ if (cs->hw_mode != hw_mode_old)
+ fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPMODEx(spi->chip_select),
+ cs->hw_mode);
}
static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)