I have sent a v3.
I tried to incorporate all of your remarks there.
Thanks
Robert
On Wed, Apr 15, 2020 at 11:33 AM Russell King - ARM Linux admin
<linux@xxxxxxxxxxxxxxx> wrote:
>
> On Tue, Apr 14, 2020 at 08:10:11PM +0200, Robert Marko wrote:
> > diff --git a/drivers/net/phy/mdio-ipq40xx.c b/drivers/net/phy/mdio-ipq40xx.c
> > new file mode 100644
> > index 000000000000..d8c11c621f20
> > --- /dev/null
> > +++ b/drivers/net/phy/mdio-ipq40xx.c
> > @@ -0,0 +1,176 @@
> > +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
> > +/* Copyright (c) 2015, The Linux Foundation. All rights reserved. */
> > +/* Copyright (c) 2020 Sartura Ltd. */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/io.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_mdio.h>
> > +#include <linux/phy.h>
> > +#include <linux/platform_device.h>
> > +
>
> Looking at how these registers are used, they could be renamed:
>
> > +#define MDIO_CTRL_0_REG 0x40
>
> This seems to be unused.
>
> > +#define MDIO_CTRL_1_REG 0x44
>
> MDIO_ADDR_REG
>
> > +#define MDIO_CTRL_2_REG 0x48
>
> MDIO_DATA_WRITE_REG
>
> > +#define MDIO_CTRL_3_REG 0x4c
>
> MDIO_DATA_READ_REG
>
> > +#define MDIO_CTRL_4_REG 0x50
> > +#define MDIO_CTRL_4_ACCESS_BUSY BIT(16)
> > +#define MDIO_CTRL_4_ACCESS_START BIT(8)
> > +#define MDIO_CTRL_4_ACCESS_CODE_READ 0
> > +#define MDIO_CTRL_4_ACCESS_CODE_WRITE 1
>
> MDIO_CMD_* ?
>
> > +
> > +#define IPQ40XX_MDIO_RETRY 1000
> > +#define IPQ40XX_MDIO_DELAY 10
> > +
> > +struct ipq40xx_mdio_data {
> > + void __iomem *membase;
> > +};
> > +
> > +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;
> > +}
> > +
> > +static int ipq40xx_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
> > +{
> > + struct ipq40xx_mdio_data *priv = bus->priv;
> > + int value = 0;
> > + unsigned int cmd = 0;
>
> No need to initialise either of these, and you can eliminate "value"
> which will then satisfy davem's requirement for reverse-christmas-tree
> ordering of variable declarations.
>
> > +
> > + /* Reject clause 45 */
> > + if (regnum & MII_ADDR_C45)
> > + return -EOPNOTSUPP;
> > +
> > + if (ipq40xx_mdio_wait_busy(bus))
> > + return -ETIMEDOUT;
> > +
> > + /* issue the phy address and reg */
> > + writel((mii_id << 8) | regnum, priv->membase + MDIO_CTRL_1_REG);
> > +
> > + cmd = MDIO_CTRL_4_ACCESS_START | MDIO_CTRL_4_ACCESS_CODE_READ;
> > +
> > + /* issue read command */
> > + writel(cmd, priv->membase + MDIO_CTRL_4_REG);
> > +
> > + /* Wait read complete */
> > + if (ipq40xx_mdio_wait_busy(bus))
> > + return -ETIMEDOUT;
> > +
> > + /* Read data */
> > + value = readl(priv->membase + MDIO_CTRL_3_REG);
> > +
> > + return value;
> > +}
> > +
> > +static int ipq40xx_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
> > + u16 value)
> > +{
> > + struct ipq40xx_mdio_data *priv = bus->priv;
> > + unsigned int cmd = 0;
>
> No need to initialise cmd.
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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