diff --git a/drivers/usb/ulpi/ulpi-viewport.c b/drivers/usb/ulpi/ulpi-viewport.c
index 72a06de910..d111680472 100644
--- a/drivers/usb/ulpi/ulpi-viewport.c
+++ b/drivers/usb/ulpi/ulpi-viewport.c
@@ -92,7 +92,8 @@ static int ulpi_request(struct ulpi_viewport *ulpi_vp, u32 value)
 
 int ulpi_write(struct ulpi_viewport *ulpi_vp, u8 *reg, u32 value)
 {
-	u32 val = ULPI_RWRUN | ULPI_RWCTRL | ((u32)reg << 16) | (value & 0xff);
+	u32 addr = (uintptr_t)reg & 0xFF;
+	u32 val = ULPI_RWRUN | ULPI_RWCTRL | addr << 16 | (value & 0xff);
 
 	val |= (ulpi_vp->port_num & 0x7) << 24;
 	return ulpi_request(ulpi_vp, val);
@@ -101,7 +102,7 @@ int ulpi_write(struct ulpi_viewport *ulpi_vp, u8 *reg, u32 value)
 u32 ulpi_read(struct ulpi_viewport *ulpi_vp, u8 *reg)
 {
 	int err;
-	u32 val = ULPI_RWRUN | ((u32)reg << 16);
+	u32 val = ULPI_RWRUN | ((uintptr_t)reg & 0xFF) << 16;
 
 	val |= (ulpi_vp->port_num & 0x7) << 24;
 	err = ulpi_request(ulpi_vp, val);
diff --git a/include/usb/ulpi.h b/include/usb/ulpi.h
index dfea395806..747fb0a9fd 100644
--- a/include/usb/ulpi.h
+++ b/include/usb/ulpi.h
@@ -123,6 +123,7 @@ int ulpi_reset(struct ulpi_viewport *ulpi_vp);
 /*
  * Write to the ULPI PHY register via the viewport.
  * @reg		- the ULPI register (one of the fields in struct ulpi_regs).
+ *		  Due to ULPI design, only 8 lsb of address are used.
  * @value	- the value - only 8 lower bits are used, others ignored.
  *
  * returns 0 on success, ULPI_ERROR on failure.
@@ -132,6 +133,7 @@ int ulpi_write(struct ulpi_viewport *ulpi_vp, u8 *reg, u32 value);
 /*
  * Read the ULPI PHY register content via the viewport.
  * @reg		- the ULPI register (one of the fields in struct ulpi_regs).
+ *		  Due to ULPI design, only 8 lsb of address are used.
  *
  * returns register content on success, ULPI_ERROR on failure.
  */