@@ -2068,6 +2068,19 @@ static int of_spi_register_master(struct spi_controller *ctlr)
}
#endif
+static int spi_controller_check_ops(struct spi_controller *ctlr)
+{
+ /*
+ * The controller must at least implement one of the ->transfer()
+ * hooks.
+ */
+ if (!ctlr->transfer && !ctlr->transfer_one &&
+ !ctlr->transfer_one_message)
+ return -EINVAL;
+
+ return 0;
+}
+
/**
* spi_register_controller - register SPI master or slave controller
* @ctlr: initialized master, originally from spi_alloc_master() or
@@ -2101,6 +2114,14 @@ int spi_register_controller(struct spi_controller *ctlr)
if (!dev)
return -ENODEV;
+ /*
+ * Make sure all necessary hooks are implemented before registering
+ * the SPI controller.
+ */
+ status = spi_controller_check_ops(ctlr);
+ if (status)
+ return status;
+
if (!spi_controller_is_slave(ctlr)) {
status = of_spi_register_master(ctlr);
if (status)