phy_read may return an error code if the underlying transport
misbehaves, e.g. a busy and non-recoverable I2C bus.
Instead of packing the error code value into the buffer, let's just
report 0xFFFF, which is the natural value used for unresponsive PHYs,
due to the pull-ups.
We could instead also return an error code, but this brings us quite a
bit of complexity, because we would need to decide:
- Either use an intermediary buffer and report an error code
immediately
- Return an incomplete count and assume that the error condition persists
to the follow-up read, so it can return the error code
Take the easy way out and just report 0xFFFF, which is generally
understood to mean unresponsive PHY.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
drivers/net/phy/mdio_bus.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index eed7c779e753..30d5aeacff0d 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -472,12 +472,13 @@ int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
static ssize_t phydev_read(struct cdev *cdev, void *_buf, size_t count, loff_t offset, ulong flags)
{
- int i = count;
+ int ret, i = count;
uint16_t *buf = _buf;
struct phy_device *phydev = cdev->priv;
while (i > 0) {
- *buf = phy_read(phydev, offset / 2);
+ ret = phy_read(phydev, offset / 2);
+ *buf = ret >= 0 ? ret : 0xffff;
buf++;
i -= 2;
offset += 2;
--
2.39.2
