Author: nbd
Date: 2015-01-24 20:42:01 +0100 (Sat, 24 Jan 2015)
New Revision: 44103

Modified:
   trunk/target/linux/generic/files/drivers/net/phy/ar8216.c
   trunk/target/linux/generic/files/drivers/net/phy/ar8216.h
Log:
ar8216: decrease page switch wait time

Until a few years ago the page switch wait time was set to msleep(1)
what was changed to usleep_range(1000, 2000) later.

I can not imagine that a low-level operation like switching page
on register level takes so much time.
Most likely the value of 1ms was initially set to check whether
it fixes an issue and then remained w/o further checking whether
also a smaller value would be sufficient.

Now the wait time is set to 5us and I successfully tested this on
AR8327. IMHO 5us should be plenty of time for all supported chips.
However I couldn't test this due to missing hardware.

If other chips should need a longer wait time we can add the
wait time as a parameter to the ar8xxx_chip struct.

Signed-off-by: Heiner Kallweit <[email protected]>

Modified: trunk/target/linux/generic/files/drivers/net/phy/ar8216.c
===================================================================
--- trunk/target/linux/generic/files/drivers/net/phy/ar8216.c   2015-01-24 
19:41:55 UTC (rev 44102)
+++ trunk/target/linux/generic/files/drivers/net/phy/ar8216.c   2015-01-24 
19:42:01 UTC (rev 44103)
@@ -260,7 +260,7 @@
        mutex_lock(&bus->mdio_lock);
 
        bus->write(bus, 0x18, 0, page);
-       usleep_range(1000, 2000); /* wait for the page switch to propagate */
+       wait_for_page_switch();
        val = mii_read32(priv, 0x10 | r2, r1);
 
        mutex_unlock(&bus->mdio_lock);
@@ -279,7 +279,7 @@
        mutex_lock(&bus->mdio_lock);
 
        bus->write(bus, 0x18, 0, page);
-       usleep_range(1000, 2000); /* wait for the page switch to propagate */
+       wait_for_page_switch();
        mii_write32(priv, 0x10 | r2, r1, val);
 
        mutex_unlock(&bus->mdio_lock);
@@ -297,7 +297,7 @@
        mutex_lock(&bus->mdio_lock);
 
        bus->write(bus, 0x18, 0, page);
-       usleep_range(1000, 2000); /* wait for the page switch to propagate */
+       wait_for_page_switch();
 
        ret = mii_read32(priv, 0x10 | r2, r1);
        ret &= ~mask;

Modified: trunk/target/linux/generic/files/drivers/net/phy/ar8216.h
===================================================================
--- trunk/target/linux/generic/files/drivers/net/phy/ar8216.h   2015-01-24 
19:41:55 UTC (rev 44102)
+++ trunk/target/linux/generic/files/drivers/net/phy/ar8216.h   2015-01-24 
19:42:01 UTC (rev 44103)
@@ -555,4 +555,10 @@
        ar8xxx_rmw(priv, reg, val, 0);
 }
 
+static inline void
+wait_for_page_switch(void)
+{
+       udelay(5);
+}
+
 #endif
_______________________________________________
openwrt-commits mailing list
[email protected]
https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-commits

Reply via email to