On 9/11/18 12:12 PM, Marek Vasut wrote:
> The SMSC95xx chip can use either the internal PHY or an external one.
> Currently, the driver hard-codes support for the internal PHY only.
>
> This patch reads out the HW_CFG register to determine whether external
> PHY is attached or not. If an external PHY is not attached, the driver
> falls back to internal PHY with fixed PHY address 0x1.
>
> If an external PHY is attached, the driver scans the entire address
> range of the MDIO bus to determine whether there is a valid external
> PHY attached. The scanning happens from the end of the address range,
> since some PHYs also respond to address 0, which is considered a MDIO
> broadcast address by them. We want to obtain their real MDIO address
> instead.
>
> Signed-off-by: Marek Vasut <ma...@denx.de>
> Cc: David S. Miller <da...@davemloft.net>
> Cc: Nisar Sayed <nisar.sa...@microchip.com>
> Cc: Woojung Huh <woojung....@microchip.com>
Expanding the CC, since I received no feedback.
Still applies cleanly on next/master.
> ---
> drivers/net/usb/smsc95xx.c | 42 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
> index 06b4d290784d..014bb71ce8a8 100644
> --- a/drivers/net/usb/smsc95xx.c
> +++ b/drivers/net/usb/smsc95xx.c
> @@ -983,6 +983,40 @@ static int smsc95xx_start_rx_path(struct usbnet *dev,
> int in_pm)
> return __smsc95xx_write_reg(dev, MAC_CR, pdata->mac_cr, in_pm);
> }
>
> +static int smsc95xx_phy_address(struct usbnet *dev)
> +{
> + u32 read_buf;
> + int ret, id1, id2, phyad;
> +
> + ret = smsc95xx_read_reg(dev, HW_CFG, &read_buf);
> + if (ret < 0)
> + return ret;
> +
> + /* Check if using external PHY, if not, use internal PHY address */
> + if (!(read_buf & HW_CFG_PSEL_))
> + return SMSC95XX_INTERNAL_PHY_ID;
> +
> + /*
> + * Detect external PHY address. Here we probe the MDIO bus from
> + * the highest address, since some PHYs respond also on address
> + * zero, which they consider MDIO broadcast address. We really
> + * want to get their proper address instead though, so we scan
> + * address zero last.
> + */
> + for (phyad = 0x1f; phyad >= 0; phyad--) {
> + id1 = smsc95xx_mdio_read(dev->net, phyad, MII_PHYSID1);
> + id2 = smsc95xx_mdio_read(dev->net, phyad, MII_PHYSID2);
> + /* Check for valid response from the PHY */
> + if (id1 > 0 && id2 > 0 && id1 != 0x7fff && id2 != 0xffff)
> + return phyad;
> + }
> +
> + /* No PHY found. */
> + netdev_warn(dev->net, "cannot detect any PHY");
> +
> + return -ENODEV;
> +}
> +
> static int smsc95xx_phy_initialize(struct usbnet *dev)
> {
> int bmcr, ret, timeout = 0;
> @@ -993,7 +1027,13 @@ static int smsc95xx_phy_initialize(struct usbnet *dev)
> dev->mii.mdio_write = smsc95xx_mdio_write;
> dev->mii.phy_id_mask = 0x1f;
> dev->mii.reg_num_mask = 0x1f;
> - dev->mii.phy_id = SMSC95XX_INTERNAL_PHY_ID;
> +
> + /* Determine PHY address */
> + ret = smsc95xx_phy_address(dev);
> + if (ret)
> + return ret;
> +
> + dev->mii.phy_id = ret;
>
> /* reset phy and wait for reset to complete */
> smsc95xx_mdio_write(dev->net, dev->mii.phy_id, MII_BMCR, BMCR_RESET);
>
