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spi_mpc83xx: fix clockrate calculation for low speed
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Commit a61f534 (spi_mpc83xx clockrate fixes) broke clockrate calculation
for low speeds.  SPMODE_DIV16 should be set if the divider is higher than
64, not only if the divider gets clipped to 1024.

Furthermore, the clipping check was off by a factor 16 as well.

Signed-off-by: Peter Korsgaard <[email protected]>
Signed-off-by: David Brownell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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jacmet authored and torvalds committed Sep 13, 2008
1 parent d7a3e49 commit 53604db
Showing 1 changed file with 5 additions and 8 deletions.
13 changes: 5 additions & 8 deletions drivers/spi/spi_mpc83xx.c
Original file line number Diff line number Diff line change
Expand Up @@ -267,16 +267,13 @@ int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
cs->hw_mode |= SPMODE_LEN(bits_per_word);

if ((mpc83xx_spi->spibrg / hz) > 64) {
cs->hw_mode |= SPMODE_DIV16;
pm = mpc83xx_spi->spibrg / (hz * 64);
if (pm > 16) {
cs->hw_mode |= SPMODE_DIV16;
pm /= 16;
if (pm > 16) {
dev_err(&spi->dev, "Requested speed is too "
"low: %d Hz. Will use %d Hz instead.\n",
hz, mpc83xx_spi->spibrg / 1024);
pm = 16;
}
dev_err(&spi->dev, "Requested speed is too "
"low: %d Hz. Will use %d Hz instead.\n",
hz, mpc83xx_spi->spibrg / 1024);
pm = 16;
}
} else
pm = mpc83xx_spi->spibrg / (hz * 4);
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