From mboxrd@z Thu Jan 1 00:00:00 1970 From: mkl@pengutronix.de (Marc Kleine-Budde) Date: Thu, 16 Sep 2010 14:09:01 +0200 Subject: colibri-pxa320/AX88796: phy-read/write problems Message-ID: <4C9208DD.8000805@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello, my hardware is a toradex colibri PXA320 board using latest stable Kernel 2.6.35.4. The Ethernet controller is a AX88796BI. Ethernet is working, but access via MDIO to the AX's internal phy is broken. The contents of all registers is 0xffff. The userspace tool "mii-diag" illustrates the problem: root at grabowski:~ mii-diag Using the default interface 'eth0'. Basic registers of MII PHY #16: ffff ffff ffff ffff ffff ffff ffff ffff. No MII transceiver present!. Use '--force' to view the information anyway. If I switch on the phy_debug in the ax88796 driver we see that the 0xffff are read via "ax_phy_read()" from the hardware, this means it's not a problem in the userspace. This is the debug output from the phy register accesses of the generic mii code, which is polling the link status every 2 seconds. [ 20.946342] ax_phy_issueaddr: dev c77ec000, 0010, 0001, 2 [ 20.946416] ax_phy_read: 0010.0001 => read ffff [ 20.946429] ax_phy_issueaddr: dev c77ec000, 0010, 0001, 2 [ 20.946502] ax_phy_read: 0010.0001 => read ffff [ 22.946336] ax_phy_issueaddr: dev c77ec000, 0010, 0001, 2 [ 22.946410] ax_phy_read: 0010.0001 => read ffff [ 22.946423] ax_phy_issueaddr: dev c77ec000, 0010, 0001, 2 [ 22.946496] ax_phy_read: 0010.0001 => read ffff Is this a known problem? It occurs with several colibri boards. Can someone with a colibri board or a different board with the ax88796 chip try to reproduce the problem. cheers, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 262 bytes Desc: OpenPGP digital signature URL: