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spi: Support transfer speed checking in the core

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Allow drivers to avoid implementing their own checks for simple rates by
specifying the limits in the master structure.

Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Mark Brown 2013-07-10 14:57:26 +01:00
parent ad81f0545e
commit a2fd4f9fa3
2 changed files with 13 additions and 0 deletions
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7
drivers/spi/spi.c
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@ -1387,6 +1387,13 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
BIT(xfer->bits_per_word - 1))) BIT(xfer->bits_per_word - 1)))
return -EINVAL; return -EINVAL;
} }
if (xfer->speed_hz && master->min_speed_hz &&
xfer->speed_hz < master->min_speed_hz)
return -EINVAL;
if (xfer->speed_hz && master->max_speed_hz &&
xfer->speed_hz > master->max_speed_hz)
return -EINVAL;
} }
message->spi = spi; message->spi = spi;

6
include/linux/spi/spi.h
View File

@ -233,6 +233,8 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* suported. If set, the SPI core will reject any transfer with an * suported. If set, the SPI core will reject any transfer with an
* unsupported bits_per_word. If not set, this value is simply ignored, * unsupported bits_per_word. If not set, this value is simply ignored,
* and it's up to the individual driver to perform any validation. * and it's up to the individual driver to perform any validation.
* @min_speed_hz: Lowest supported transfer speed
* @max_speed_hz: Highest supported transfer speed
* @flags: other constraints relevant to this driver * @flags: other constraints relevant to this driver
* @bus_lock_spinlock: spinlock for SPI bus locking * @bus_lock_spinlock: spinlock for SPI bus locking
* @bus_lock_mutex: mutex for SPI bus locking * @bus_lock_mutex: mutex for SPI bus locking
@ -312,6 +314,10 @@ struct spi_master {
#define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0UL : (BIT(bits) - 1)) #define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0UL : (BIT(bits) - 1))
#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1)) #define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1))
/* limits on transfer speed */
u32 min_speed_hz;
u32 max_speed_hz;
/* other constraints relevant to this driver */ /* other constraints relevant to this driver */
u16 flags; u16 flags;
#define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ #define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */