From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Trumtrar Subject: [RFC] net: stmmac: socfpga: dt binding Date: Thu, 13 Aug 2015 21:41:05 +0200 Message-ID: <20150813194105.GC9841@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dinh Nguyen Cc: Rob Herring , Pawel Moll , Mark Rutland , Kumar Gala , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "David S. Miller" List-Id: devicetree@vger.kernel.org Hi! I'm in the middle of getting the IEEE1588/PTP features of the GMAC up and running. The problem I have is with the current binding however. The documentation says: Example: gmac0: ethernet@ff700000 { compatible = "altr,socfpga-stmmac", "snps,dwmac-3.70a", "snps,dwmac"; altr,sysmgr-syscon = <&sysmgr 0x60 0>; status = "disabled"; reg = <0xff700000 0x2000>; interrupts = <0 115 4>; interrupt-names = "macirq"; mac-address = [00 00 00 00 00 00];/* Filled in by U-Boot */ clocks = <&emac_0_clk>; clock-names = "stmmaceth"; }; The problem is with the "altr,sysmgr-syscon" property. It was invented, because the Arria10 and the Arria5/CycloneV have different register offsets and shifts. This information is however not enough to describe all properties of the hardware, but more of a crutch IMHO. The shifts are for the PHYSEL bits. Of course now I need some different shifts AND I need to access an additional register with different shifts on Arria10 and CycloneV in the sysmgr. So, the standard way of handling this is with a new compatible for each type and getting rid of the register offset and shift in the property, I guess. And test the DT and print a deprecation warning if the property is still there. Do you see any other/better way of fixing this? As a side note: Is it reasonable to use the "clk_ptp_ref" property of the stmmac to decide if the PTP features should be enabled or not? As the hardware needs to be configured to use this clock, I think the presence of this property is a good enough indicator. Regards, Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html