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spi: check bits_per_word in spi_setup

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This allows drivers for devices connected via SPI to check if the
controller supports a given bits_per_word value during setup.
Currently any BPW value is accepted durings setup, and transfers
are rejected later.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Stefan Brüns 2015-08-23 16:06:30 +02:00 committed by Mark Brown
parent 7dc9fbc342
commit 63ab645f4d
1 changed files with 19 additions and 8 deletions
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27
drivers/spi/spi.c
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@ -1740,6 +1740,20 @@ EXPORT_SYMBOL_GPL(spi_busnum_to_master);
* other core methods are currently defined as inline functions.
*/
static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
{
if (master->bits_per_word_mask) {
/* Only 32 bits fit in the mask */
if (bits_per_word > 32)
return -EINVAL;
if (!(master->bits_per_word_mask &
SPI_BPW_MASK(bits_per_word)))
return -EINVAL;
}
return 0;
}
/**
* spi_setup - setup SPI mode and clock rate
* @spi: the device whose settings are being modified
@ -1798,6 +1812,9 @@ int spi_setup(struct spi_device *spi)
if (!spi->bits_per_word)
spi->bits_per_word = 8;
if (__spi_validate_bits_per_word(spi->master, spi->bits_per_word))
return -EINVAL;
if (!spi->max_speed_hz)
spi->max_speed_hz = spi->master->max_speed_hz;
@ -1867,14 +1884,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
xfer->speed_hz > master->max_speed_hz)
xfer->speed_hz = master->max_speed_hz;
if (master->bits_per_word_mask) {
/* Only 32 bits fit in the mask */
if (xfer->bits_per_word > 32)
return -EINVAL;
if (!(master->bits_per_word_mask &
BIT(xfer->bits_per_word - 1)))
return -EINVAL;
}
if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
return -EINVAL;
/*
* SPI transfer length should be multiple of SPI word size