From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH net-next v2 3/8] net: phy: meson-gxl: add read and write helpers for bank registers Date: Fri, 8 Dec 2017 09:11:17 +0000 Message-ID: <20171208091116.GZ10595@n2100.armlinux.org.uk> References: <20171207142715.32578-1-jbrunet@baylibre.com> <20171207142715.32578-4-jbrunet@baylibre.com> <20171207154610.GG24750@lunn.ch> <1512661873.7042.9.camel@baylibre.com> <20171207160235.GL24750@lunn.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jerome Brunet , Florian Fainelli , Kevin Hilman , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org To: Andrew Lunn Return-path: Content-Disposition: inline In-Reply-To: <20171207160235.GL24750@lunn.ch> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Dec 07, 2017 at 05:02:35PM +0100, Andrew Lunn wrote: > > Banks actually comes from the datasheet, Yes. > > I don't mind renaming it but I would be making things up. As you wish ? > > Keep it as is for the moment. > > > Does the usual pages comes with this weird toggle thing to open the access ? > > Would we able to use these generic helpers with our this kind of quirks ? > > I don't think the API has been defined yet. But what has been > discussed is adding functions to struct phy_driver. The driver can > then implement whatever is needed to select a given page. There will > then be helpers which take the lock, select the page, do the > read/write, select page 0, and unlock. I'm not sure adding generic helpers really works, because the indirection through phy_driver just makes the code more complex. For Marvell, I ended up with: http://git.armlinux.org.uk/cgit/linux-arm.git/commit/?h=phy&id=9ca46084228bb1b8851e7d24276d85c4ec6e13ae and the preceding three commits. The "generic" versions I came up with were basically lifting marvell_read_paged(), marvell_write_paged() and marvell_modify_paged() to phylib, along with the lower leve marvell_save_page(), marvell_select_page() and marvell_restore_page(). The result is a fair amount of out-of-line code and an assumption that it's a single register. As soon as a PHY has other requirements, these generic implementations don't work. Also, unfortunately, we can't get help from sparse for statically checking the locking - the __acquire()/__release() annotations don't work for mutexes. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up