Commit a2fd4f9f authored by Mark Brown's avatar Mark Brown
Browse files

spi: Support transfer speed checking in the core 



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

Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent ad81f054

drivers/spi/spi.c

+7 −0
Original line number Diff line number Diff line
@@ -1387,6 +1387,13 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message) 
					BIT(xfer->bits_per_word - 1)))

				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;

include/linux/spi/spi.h

+6 −0
Original line number Diff line number Diff line
@@ -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

 *	unsupported bits_per_word. If not set, this value is simply ignored,

 *	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

 * @bus_lock_spinlock: spinlock 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_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 */

	u16			flags;

#define SPI_MASTER_HALF_DUPLEX	BIT(0)		/* can't do full duplex */