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spi/fsl-espi: Make sure pm is within 2..32 

The reference manual says that pm has to stay within 2 and 32. So the
lowest frequency is 32 and DIV16 set, the highest is 2 and DIV16 unset.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Sebastian Andrzej Siewior 2012-03-15 18:42:32 +01:00 committed by Grant Likely
parent 35faa55cff
commit 87bf5ab828
1 changed files with 6 additions and 4 deletions
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10
drivers/spi/spi-fsl-espi.c
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@ -182,16 +182,18 @@ static int fsl_espi_setup_transfer(struct spi_device *spi,
cs->hw_mode |= CSMODE_DIV16;
pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 16 * 4);
WARN_ONCE(pm > 16, "%s: Requested speed is too low: %d Hz. "
WARN_ONCE(pm > 33, "%s: Requested speed is too low: %d Hz. "
"Will use %d Hz instead.\n", dev_name(&spi->dev),
hz, mpc8xxx_spi->spibrg / 1024);
if (pm > 16)
pm = 16;
hz, mpc8xxx_spi->spibrg / (4 * 16 * (32 + 1)));
if (pm > 33)
pm = 33;
} else {
pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 4);
}
if (pm)
pm--;
if (pm < 2)
pm = 2;
cs->hw_mode |= CSMODE_PM(pm);