diff options
Diffstat (limited to 'include/linux/spi')
| -rw-r--r-- | include/linux/spi/spi.h | 83 |
1 files changed, 47 insertions, 36 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 072cb2aa2413..4b743ac35396 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -312,6 +312,8 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @flags: other constraints relevant to this driver * @max_transfer_size: function that returns the max transfer size for * a &spi_device; may be %NULL, so the default %SIZE_MAX will be used. + * @max_message_size: function that returns the max message size for + * a &spi_device; may be %NULL, so the default %SIZE_MAX will be used. * @io_mutex: mutex for physical bus access * @bus_lock_spinlock: spinlock for SPI bus locking * @bus_lock_mutex: mutex for exclusion of multiple callers @@ -442,10 +444,11 @@ struct spi_master { #define SPI_MASTER_MUST_TX BIT(4) /* requires tx */ /* - * on some hardware transfer size may be constrained + * on some hardware transfer / message size may be constrained * the limit may depend on device transfer settings */ size_t (*max_transfer_size)(struct spi_device *spi); + size_t (*max_message_size)(struct spi_device *spi); /* I/O mutex */ struct mutex io_mutex; @@ -905,12 +908,26 @@ extern int spi_async_locked(struct spi_device *spi, struct spi_message *message); static inline size_t -spi_max_transfer_size(struct spi_device *spi) +spi_max_message_size(struct spi_device *spi) { struct spi_master *master = spi->master; - if (!master->max_transfer_size) + if (!master->max_message_size) return SIZE_MAX; - return master->max_transfer_size(spi); + return master->max_message_size(spi); +} + +static inline size_t +spi_max_transfer_size(struct spi_device *spi) +{ + struct spi_master *master = spi->master; + size_t tr_max = SIZE_MAX; + size_t msg_max = spi_max_message_size(spi); + + if (master->max_transfer_size) + tr_max = master->max_transfer_size(spi); + + /* transfer size limit must not be greater than messsage size limit */ + return min(tr_max, msg_max); } /*---------------------------------------------------------------------------*/ @@ -980,6 +997,30 @@ extern int spi_bus_lock(struct spi_master *master); extern int spi_bus_unlock(struct spi_master *master); /** + * spi_sync_transfer - synchronous SPI data transfer + * @spi: device with which data will be exchanged + * @xfers: An array of spi_transfers + * @num_xfers: Number of items in the xfer array + * Context: can sleep + * + * Does a synchronous SPI data transfer of the given spi_transfer array. + * + * For more specific semantics see spi_sync(). + * + * Return: Return: zero on success, else a negative error code. + */ +static inline int +spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers, + unsigned int num_xfers) +{ + struct spi_message msg; + + spi_message_init_with_transfers(&msg, xfers, num_xfers); + + return spi_sync(spi, &msg); +} + +/** * spi_write - SPI synchronous write * @spi: device to which data will be written * @buf: data buffer @@ -998,11 +1039,8 @@ spi_write(struct spi_device *spi, const void *buf, size_t len) .tx_buf = buf, .len = len, }; - struct spi_message m; - spi_message_init(&m); - spi_message_add_tail(&t, &m); - return spi_sync(spi, &m); + return spi_sync_transfer(spi, &t, 1); } /** @@ -1024,35 +1062,8 @@ spi_read(struct spi_device *spi, void *buf, size_t len) .rx_buf = buf, .len = len, }; - struct spi_message m; - - spi_message_init(&m); - spi_message_add_tail(&t, &m); - return spi_sync(spi, &m); -} -/** - * spi_sync_transfer - synchronous SPI data transfer - * @spi: device with which data will be exchanged - * @xfers: An array of spi_transfers - * @num_xfers: Number of items in the xfer array - * Context: can sleep - * - * Does a synchronous SPI data transfer of the given spi_transfer array. - * - * For more specific semantics see spi_sync(). - * - * Return: Return: zero on success, else a negative error code. - */ -static inline int -spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers, - unsigned int num_xfers) -{ - struct spi_message msg; - - spi_message_init_with_transfers(&msg, xfers, num_xfers); - - return spi_sync(spi, &msg); + return spi_sync_transfer(spi, &t, 1); } /* this copies txbuf and rxbuf data; for small transfers only! */ |