diff options
| author | Heiner Kallweit <hkallweit1@gmail.com> | 2016-11-04 21:01:12 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2016-11-04 14:46:39 -0600 |
| commit | 8f3086d2a9c1104f42d2d0247ef52b01c6d898d8 (patch) | |
| tree | 26e56443abcf6ac574670471a5fe5e88ef69cf6a /drivers/spi/spi-fsl-espi.c | |
| parent | 60d9531a61efc8e6b69d04089d50a0a929090fe1 (diff) | |
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>
Diffstat (limited to 'drivers/spi/spi-fsl-espi.c')
| -rw-r--r-- | drivers/spi/spi-fsl-espi.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c index 1029bd2ff5f1..edb524f831a3 100644 --- a/drivers/spi/spi-fsl-espi.c +++ b/drivers/spi/spi-fsl-espi.c @@ -249,6 +249,7 @@ static void fsl_espi_setup_transfer(struct spi_device *spi, 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 @@ static void fsl_espi_setup_transfer(struct spi_device *spi, 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) |