r8169: fix mdio_read and update mdio_write according to hw specs
Realtek confirmed that a 20us delay is needed after mdio_read and
mdio_write operations. Reduce the delay in mdio_write, and add it
to mdio_read too. Also add a comment that the 20us is from hw specs.
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Acked-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index 03a8318..96b6cfb 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -560,10 +560,10 @@
udelay(25);
}
/*
- * Some configurations require a small delay even after the write
- * completed indication or the next write might fail.
+ * According to hardware specs a 20us delay is required after write
+ * complete indication, but before sending next command.
*/
- udelay(25);
+ udelay(20);
}
static int mdio_read(void __iomem *ioaddr, int reg_addr)
@@ -583,6 +583,12 @@
}
udelay(25);
}
+ /*
+ * According to hardware specs a 20us delay is required after read
+ * complete indication, but before sending next command.
+ */
+ udelay(20);
+
return value;
}