diff options
| author | Dragos Bogdan <dragos.bogdan@analog.com> | 2020-12-21 17:29:35 +0200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2020-12-28 14:21:31 +0000 |
| commit | d962608ce2188a1d46ec9d356d6fad5cd6fc0341 (patch) | |
| tree | e129ab2ad7f2227640351917584bbf0ebb65da6e /include/linux/spi | |
| parent | f7005142dacea1769fba0152c493aaa61b33205c (diff) | |
spi: Add SPI_NO_TX/RX support
Transmit/receive only is a valid SPI mode. For example, the MOSI/TX line
might be missing from an ADC while for a DAC the MISO/RX line may be
optional. This patch adds these two new modes: SPI_NO_TX and
SPI_NO_RX. This way, the drivers will be able to identify if any of
these two lines is missing and to adjust the transfers accordingly.
Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201221152936.53873-2-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include/linux/spi')
| -rw-r--r-- | include/linux/spi/spi.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index a08c3f37e202..9bfdfaf286eb 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -6,6 +6,7 @@ #ifndef __LINUX_SPI_H #define __LINUX_SPI_H +#include <linux/bits.h> #include <linux/device.h> #include <linux/mod_devicetable.h> #include <linux/slab.h> @@ -166,6 +167,18 @@ struct spi_device { u8 chip_select; u8 bits_per_word; bool rt; +#define SPI_NO_TX BIT(31) /* no transmit wire */ +#define SPI_NO_RX BIT(30) /* no receive wire */ + /* + * All bits defined above should be covered by SPI_MODE_KERNEL_MASK. + * The SPI_MODE_KERNEL_MASK has the SPI_MODE_USER_MASK counterpart, + * which is defined in 'include/uapi/linux/spi/spi.h'. + * The bits defined here are from bit 31 downwards, while in + * SPI_MODE_USER_MASK are from 0 upwards. + * These bits must not overlap. A static assert check should make sure of that. + * If adding extra bits, make sure to decrease the bit index below as well. + */ +#define SPI_MODE_KERNEL_MASK (~(BIT(30) - 1)) u32 mode; int irq; void *controller_state; @@ -189,6 +202,10 @@ struct spi_device { */ }; +/* Make sure that SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK don't overlap */ +static_assert((SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK) == 0, + "SPI_MODE_USER_MASK & SPI_MODE_KERNEL_MASK must not overlap"); + static inline struct spi_device *to_spi_device(struct device *dev) { return dev ? container_of(dev, struct spi_device, dev) : NULL; |