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spi: fsl-espi: don't write ESPI_SPMODE register if the mode doesn't change

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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>
This commit is contained in:
Heiner Kallweit
2016-11-04 21:01:12 +01:00
committed by Mark Brown
parent 60d9531a61
commit 8f3086d2a9
1 changed files with 5 additions and 2 deletions
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3
drivers/spi/spi-fsl-espi.c
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@@ -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; int bits_per_word = t ? t->bits_per_word : spi->bits_per_word;
u32 pm, hz = t ? t->speed_hz : spi->max_speed_hz; u32 pm, hz = t ? t->speed_hz : spi->max_speed_hz;
struct spi_mpc8xxx_cs *cs = spi->controller_state; struct spi_mpc8xxx_cs *cs = spi->controller_state;
u32 hw_mode_old = cs->hw_mode;
/* mask out bits we are going to set */ /* mask out bits we are going to set */
cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF)); cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF));
@@ -271,6 +272,8 @@ static void fsl_espi_setup_transfer(struct spi_device *spi,
cs->hw_mode |= CSMODE_PM(pm); cs->hw_mode |= CSMODE_PM(pm);
/* 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), fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPMODEx(spi->chip_select),
cs->hw_mode); cs->hw_mode);
} }