From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A423EC43331 for ; Tue, 12 Jan 2021 21:41:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 698F223122 for ; Tue, 12 Jan 2021 21:41:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731345AbhALVhn (ORCPT ); Tue, 12 Jan 2021 16:37:43 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:36586 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437024AbhALUoL (ORCPT ); Tue, 12 Jan 2021 15:44:11 -0500 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1kzQVl-000ECn-ED; Tue, 12 Jan 2021 21:43:29 +0100 Date: Tue, 12 Jan 2021 21:43:29 +0100 From: Andrew Lunn To: Marek =?iso-8859-1?Q?Beh=FAn?= Cc: netdev@vger.kernel.org, Russell King , Jakub Kicinski , davem@davemloft.net, pali@kernel.org Subject: Re: [PATCH net-next v4 1/4] net: phy: mdio-i2c: support I2C MDIO protocol for RollBall SFP modules Message-ID: References: <20210111050044.22002-1-kabel@kernel.org> <20210111050044.22002-2-kabel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210111050044.22002-2-kabel@kernel.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > +/* RollBall SFPs do not access internal PHY via I2C address 0x56, but > + * instead via address 0x51, when SFP page is set to 0x03 and password to > + * 0xffffffff. > + * Since current SFP code does not modify SFP_PAGE, we set it to 0x03 only at > + * bus creation time, and expect it to remain set to 0x03 throughout the > + * lifetime of the module plugged into the system. If the SFP code starts > + * modifying SFP_PAGE in the future, this code will need to change. ... > +/* In order to not interfere with other SFP code (which possibly may manipulate > + * SFP_PAGE), for every transfer we do this: > + * 1. lock the bus > + * 2. save content of SFP_PAGE > + * 3. set SFP_PAGE to 3 > + * 4. do the transfer > + * 5. restore original SFP_PAGE > + * 6. unlock the bus These two comments seem to contradict each other? > +static int i2c_rollball_mii_poll(struct mii_bus *bus, int bus_addr, u8 *buf, > + size_t len) > +{ > + struct i2c_adapter *i2c = bus->priv; > + struct i2c_msg msgs[2]; > + u8 cmd_addr, tmp, *res; > + int i, ret; > + > + cmd_addr = ROLLBALL_CMD_ADDR; > + > + res = buf ? buf : &tmp; > + len = buf ? len : 1; > + > + msgs[0].addr = bus_addr; > + msgs[0].flags = 0; > + msgs[0].len = 1; > + msgs[0].buf = &cmd_addr; > + > + msgs[1].addr = bus_addr; > + msgs[1].flags = I2C_M_RD; > + msgs[1].len = len; > + msgs[1].buf = res; > + > + /* By experiment it takes up to 70 ms to access a register for these > + * SFPs. Sleep 20ms between iteratios and try 10 times. > + */ iterations > +static int i2c_mii_read_rollball(struct mii_bus *bus, int phy_id, int reg) > +{ > + u8 buf[4], res[6]; > + int bus_addr, ret; > + u16 val; > + > + if (!(reg & MII_ADDR_C45)) > + return -EOPNOTSUPP; > + > + bus_addr = i2c_mii_phy_addr(phy_id); > + if (bus_addr != ROLLBALL_PHY_I2C_ADDR) > + return 0xffff; > + > + buf[0] = ROLLBALL_DATA_ADDR; > + buf[1] = (reg >> 16) & 0x1f; > + buf[2] = (reg >> 8) & 0xff; > + buf[3] = reg & 0xff; This looks odd. There are only 32 registers for C22 transactions, so it fits in one byte. You can set buf[1] and buf[2] to zero. C45 transactions allow for 65536 registers, and has the devtype field, so would need 3 bytes. Which suggests that C45 might actually be supported? At least by the protocol, if not the device. > + dev_dbg(&bus->dev, "read reg %02x:%04x = %04x\n", (reg >> 16) & 0x1f, > + reg & 0xffff, val); There is a tracepoint that allows access to this information, so you can probably remove this. Andrew