Merge remote-tracking branches 'spi/topic/fsl-espi', 'spi/topic/imx', 'spi/topic...

[cascardo/linux.git] / include / linux / spi / spi.h

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 072cb2a..4b743ac 100644 (file)
--- 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);
 }
 
 /*---------------------------------------------------------------------------*/
@@ -979,6 +996,30 @@ extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message);
 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
@@ -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! */