usb: renesas_usbhs: add DMAEngine ID specification note
renesas_usbhs DMAEngine uses D0FIFO/D1FIFO,
but the data transfer direction should be fixed for keeping consistency.
This patch explain about it on renesas_usbhs.h
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/usb/renesas_usbhs.h b/include/linux/usb/renesas_usbhs.h
index 547e59c..c5d36c6 100644
--- a/include/linux/usb/renesas_usbhs.h
+++ b/include/linux/usb/renesas_usbhs.h
@@ -132,6 +132,14 @@
* option:
*
* dma id for dmaengine
+ * The data transfer direction on D0FIFO/D1FIFO should be
+ * fixed for keeping consistency.
+ * So, the platform id settings will be..
+ * .d0_tx_id = xx_TX,
+ * .d1_rx_id = xx_RX,
+ * or
+ * .d1_tx_id = xx_TX,
+ * .d0_rx_id = xx_RX,
*/
int d0_tx_id;
int d0_rx_id;