Hi Arnd again, > From: Yoshihiro Shimoda > Sent: Wednesday, December 16, 2015 10:43 AM < snip > > > > +static void usb3_write(struct renesas_usb3 *usb3, u32 data, u32 offs) > > > +{ > > > + iowrite32(data, usb3->reg + offs); > > > +} > > > + > > > +static u32 usb3_read(struct renesas_usb3 *usb3, u32 offs) > > > +{ > > > + return ioread32(usb3->reg + offs); > > > +} > > > > I think using readl() is more common than ioread32() if the driver cannot > > use IORESOURCE_IO but only IORESOURCE_MEM. > > > > On ARM, the two are the same, but on some architectures ioread32 is more > > expensive, so using the former is preferred. > > I will use {read,write}l() instead of io{read,write}32(). > Also I will change io{read,write}32_rep() functions too. Oops. If I used {read,write}sl() instead of io{read,write}32_rep(), build error happened in x86 environment. CC [M] drivers/usb/gadget/udc/renesas_usb3.o ./drivers/usb/gadget/udc/renesas_usb3.c: In function 'usb3_write_pipe': ./drivers/usb/gadget/udc/renesas_usb3.c:879:3: error: implicit declaration of function 'writesl' [-Werror=implicit-function-declaration] writesl(usb3->reg + fifo_reg, buf, len / 4); ^ ./drivers/usb/gadget/udc/renesas_usb3.c: In function 'usb3_read_pipe': ./drivers/usb/gadget/udc/renesas_usb3.c:923:3: error: implicit declaration of function 'readsl' [-Werror=implicit-function-declaration] readsl(usb3->reg + fifo_reg, buf, len / 4); So, I will keep to use io{read,write}32(_rep) functions. Best regards, Yoshihiro Shimoda -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html