From patchwork Tue Jul 10 22:24:22 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 942269 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 41QGvz3Nm7z9s2L for ; Wed, 11 Jul 2018 08:24:31 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732347AbeGJWZj (ORCPT ); Tue, 10 Jul 2018 18:25:39 -0400 Received: from sauhun.de ([88.99.104.3]:45910 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732332AbeGJWZj (ORCPT ); Tue, 10 Jul 2018 18:25:39 -0400 Received: from localhost (p54B33462.dip0.t-ipconnect.de [84.179.52.98]) by pokefinder.org (Postfix) with ESMTPSA id E6E9656A487; Wed, 11 Jul 2018 00:24:28 +0200 (CEST) From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, Yoshihiro Shimoda , Wolfram Sang Subject: [PATCH 1/2] i2c: recovery: add get_bus_free callback Date: Wed, 11 Jul 2018 00:24:22 +0200 Message-Id: <20180710222423.7792-2-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180710222423.7792-1-wsa+renesas@sang-engineering.com> References: <20180710222423.7792-1-wsa+renesas@sang-engineering.com> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Some IP cores have an internal 'bus free' logic which may be more advanced than just checking if SDA is high. Add a separate callback to get this status. Filling it is optional. Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core-base.c | 27 +++++++++++++++++++++++---- include/linux/i2c.h | 3 +++ 2 files changed, 26 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index c7995efd58ea..59f8dfc5be36 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -158,6 +158,22 @@ static void set_sda_gpio_value(struct i2c_adapter *adap, int val) gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val); } +static int i2c_generic_bus_free(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + int ret = -EOPNOTSUPP; + + if (bri->get_bus_free) + ret = bri->get_bus_free(adap); + else if (bri->get_sda) + ret = bri->get_sda(adap); + + if (ret < 0) + return ret; + + return ret ? 0 : -EBUSY; +} + /* * We are generating clock pulses. ndelay() determines durating of clk pulses. * We will generate clock with rate 100 KHz and so duration of both clock levels @@ -169,7 +185,7 @@ static void set_sda_gpio_value(struct i2c_adapter *adap, int val) int i2c_generic_scl_recovery(struct i2c_adapter *adap) { struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; - int i = 0, val = 1, ret = 0; + int i = 0, val = 1, ret; if (bri->prepare_recovery) bri->prepare_recovery(adap); @@ -207,14 +223,17 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) bri->set_sda(adap, val); ndelay(RECOVERY_NDELAY / 2); - /* Break if SDA is high */ - if (val && bri->get_sda) { - ret = bri->get_sda(adap) ? 0 : -EBUSY; + if (val) { + ret = i2c_generic_bus_free(adap); if (ret == 0) break; } } + /* If we can't check bus status, assume recovery worked */ + if (ret == -EOPNOTSUPP) + ret = 0; + if (bri->unprepare_recovery) bri->unprepare_recovery(adap); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 9d1818c56775..60e224428a85 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -587,6 +587,8 @@ struct i2c_timings { * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for * generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO, * for generic GPIO recovery. + * @get_bus_free: Returns the bus free state as seen from the IP core in case it + * has a more complex internal logic than just reading SDA. Optional. * @prepare_recovery: This will be called before starting recovery. Platform may * configure padmux here for SDA/SCL line or something else they want. * @unprepare_recovery: This will be called after completing recovery. Platform @@ -601,6 +603,7 @@ struct i2c_bus_recovery_info { void (*set_scl)(struct i2c_adapter *adap, int val); int (*get_sda)(struct i2c_adapter *adap); void (*set_sda)(struct i2c_adapter *adap, int val); + int (*get_bus_free)(struct i2c_adapter *adap); void (*prepare_recovery)(struct i2c_adapter *adap); void (*unprepare_recovery)(struct i2c_adapter *adap);