Hi Robert This is looking better > +#include <linux/delay.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/mutex.h> I don't think you need this header. There are no mutexes here. > +#include <linux/io.h> > +#include <linux/of_address.h> > +#include <linux/of_mdio.h> > +#include <linux/phy.h> > +#include <linux/platform_device.h> > + > +#define MDIO_CTRL_0_REG 0x40 > +#define MDIO_CTRL_1_REG 0x44 > +#define MDIO_CTRL_2_REG 0x48 > +#define MDIO_CTRL_3_REG 0x4c > +#define MDIO_CTRL_4_REG 0x50 So your next version will hopefully have better names. > +static int ipq40xx_mdio_wait_busy(struct mii_bus *bus) > +{ > + struct ipq40xx_mdio_data *priv = bus->priv; > + int i; > + > + for (i = 0; i < IPQ40XX_MDIO_RETRY; i++) { > + unsigned int busy; > + > + busy = readl(priv->membase + MDIO_CTRL_4_REG) & > + MDIO_CTRL_4_ACCESS_BUSY; > + if (!busy) > + return 0; > + > + /* BUSY might take to be cleard by 15~20 times of loop */ > + udelay(IPQ40XX_MDIO_DELAY); > + } > + > + dev_err(bus->parent, "MDIO operation timed out\n"); > + > + return -ETIMEDOUT; > +} You can probably make use of include/linux/iopoll.h Andrew