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spi: spi_mpc83xx clockrate fixes
This updates the SPI clock rate calculations for the spi_mpc83xx driver. Some boundary conditions were wrong, and in several cases divide-by-16 wasn't always needed Signed-off-by: Chen Gong <g.chen@freescale.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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708d8cefd0
commit
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1 changed files with 16 additions and 13 deletions
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@ -266,21 +266,24 @@ int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
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cs->hw_mode |= SPMODE_LEN(bits_per_word);
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if ((mpc83xx_spi->spibrg / hz) >= 64) {
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pm = mpc83xx_spi->spibrg / (hz * 64) - 1;
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if (pm > 0x0f) {
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dev_err(&spi->dev, "Requested speed is too "
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"low: %d Hz. Will use %d Hz instead.\n",
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hz, mpc83xx_spi->spibrg / 1024);
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pm = 0x0f;
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if ((mpc83xx_spi->spibrg / hz) > 64) {
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pm = mpc83xx_spi->spibrg / (hz * 64);
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if (pm > 16) {
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cs->hw_mode |= SPMODE_DIV16;
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pm /= 16;
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if (pm > 16) {
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dev_err(&spi->dev, "Requested speed is too "
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"low: %d Hz. Will use %d Hz instead.\n",
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hz, mpc83xx_spi->spibrg / 1024);
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pm = 16;
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}
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}
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cs->hw_mode |= SPMODE_PM(pm) | SPMODE_DIV16;
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} else {
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} else
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pm = mpc83xx_spi->spibrg / (hz * 4);
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if (pm)
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pm--;
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cs->hw_mode |= SPMODE_PM(pm);
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}
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if (pm)
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pm--;
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cs->hw_mode |= SPMODE_PM(pm);
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regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
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if (cs->hw_mode != regval) {
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unsigned long flags;
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