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| author | Stephen Warren <swarren@wwwdotorg.org> | 2013-03-26 20:37:57 -0600 |
|---|---|---|
| committer | Mark Brown <broonie@opensource.wolfsonmicro.com> | 2013-04-01 14:14:32 +0100 |
| commit | 543bb255a1987836e64f5b7a63664ead8b32b042 (patch) | |
| tree | 818ee5b60f8d24ccfd495ebdb50ea0a175c340b1 | |
| parent | 5c725b34d438fdd3c528673a5f53f4b07f879c68 (diff) | |
| download | lwn-543bb255a1987836e64f5b7a63664ead8b32b042.tar.gz lwn-543bb255a1987836e64f5b7a63664ead8b32b042.zip | |
spi: add ability to validate xfer->bits_per_word in SPI core
Allow SPI masters to define the set of bits_per_word values they support.
If they do this, then the SPI core will reject transfers that attempt to
use an unsupported bits_per_word value. This eliminates the need for each
SPI driver to implement this checking in most cases.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
| -rw-r--r-- | drivers/spi/spi.c | 8 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 8 |
2 files changed, 16 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index f996c600eb8c..0cabf1560550 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1377,6 +1377,14 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message) xfer->bits_per_word = spi->bits_per_word; if (!xfer->speed_hz) xfer->speed_hz = spi->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; + } } message->spi = spi; diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 38c2b925923d..733eb5ee31c5 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -228,6 +228,11 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * every chipselect is connected to a slave. * @dma_alignment: SPI controller constraint on DMA buffers alignment. * @mode_bits: flags understood by this controller driver + * @bits_per_word_mask: A mask indicating which values of bits_per_word are + * supported by the driver. Bit n indicates that a bits_per_word n+1 is + * suported. If set, the SPI core will reject any transfer with an + * unsupported bits_per_word. If not set, this value is simply ignored, + * and it's up to the individual driver to perform any validation. * @flags: other constraints relevant to this driver * @bus_lock_spinlock: spinlock for SPI bus locking * @bus_lock_mutex: mutex for SPI bus locking @@ -301,6 +306,9 @@ struct spi_master { /* spi_device.mode flags understood by this controller driver */ u16 mode_bits; + /* bitmask of supported bits_per_word for transfers */ + u32 bits_per_word_mask; + /* other constraints relevant to this driver */ u16 flags; #define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ |