+ /*
+ * SPI transfer length should be multiple of SPI word size
+ * where SPI word size should be power-of-two multiple
+ */
+ if (xfer->bits_per_word <= 8)
+ w_size = 1;
+ else if (xfer->bits_per_word <= 16)
+ w_size = 2;
+ else
+ w_size = 4;
+
+ /* No partial transfers accepted */
+ if (xfer->len % w_size)
+ return -EINVAL;
+