From patchwork Mon Dec 4 12:36:40 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 844224 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=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3yr4CT39yHz9t3r for ; Mon, 4 Dec 2017 23:37:41 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752837AbdLDMhk (ORCPT ); Mon, 4 Dec 2017 07:37:40 -0500 Received: from sauhun.de ([88.99.104.3]:44221 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753327AbdLDMhj (ORCPT ); Mon, 4 Dec 2017 07:37:39 -0500 Received: from localhost (unknown [46.183.103.17]) by pokefinder.org (Postfix) with ESMTPSA id 409932C6484; Mon, 4 Dec 2017 13:37:38 +0100 (CET) From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, Wolfram Sang , Phil Reid , Andy Shevchenko , Jarkko Nikula , Claudio Foellmi , Andrzej Hajda Subject: [PATCH 6/6] i2c: rcar: implement bus recovery Date: Mon, 4 Dec 2017 13:36:40 +0100 Message-Id: <20171204123640.3382-7-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171204123640.3382-1-wsa+renesas@sang-engineering.com> References: <20171204123640.3382-1-wsa+renesas@sang-engineering.com> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org We can force levels of SCL and SDA, so we can use that for bus recovery. Note that we cannot read SDA back, because we will only get the internal state of the bus free detection. Cc: Phil Reid Cc: Andy Shevchenko Cc: Jarkko Nikula Cc: Claudio Foellmi Cc: Andrzej Hajda Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-rcar.c | 54 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 52 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 8a2ae3e6c561c4..d4b7b5380c2983 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -132,6 +132,7 @@ struct rcar_i2c_priv { int pos; u32 icccr; u32 flags; + u8 recovery_icmcr; /* protected by adapter lock */ enum rcar_i2c_type devtype; struct i2c_client *slave; @@ -158,6 +159,46 @@ static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg) return readl(priv->io + reg); } +static int rcar_i2c_get_scl(struct i2c_adapter *adap) +{ + struct rcar_i2c_priv *priv = i2c_get_adapdata(adap); + + return !!(rcar_i2c_read(priv, ICMCR) & FSCL); + +}; + +static void rcar_i2c_set_scl(struct i2c_adapter *adap, int val) +{ + struct rcar_i2c_priv *priv = i2c_get_adapdata(adap); + + if (val) + priv->recovery_icmcr |= FSCL; + else + priv->recovery_icmcr &= ~FSCL; + + rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr); +}; + +/* No get_sda, because the HW only reports its bus free logic, not SDA itself */ + +static void rcar_i2c_set_sda(struct i2c_adapter *adap, int val) +{ + struct rcar_i2c_priv *priv = i2c_get_adapdata(adap); + + if (val) + priv->recovery_icmcr |= FSDA; + else + priv->recovery_icmcr &= ~FSDA; + + rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr); +}; + +static struct i2c_bus_recovery_info rcar_i2c_bri = { + .get_scl = rcar_i2c_get_scl, + .set_scl = rcar_i2c_set_scl, + .set_sda = rcar_i2c_set_sda, + .recover_bus = i2c_generic_scl_recovery, +}; static void rcar_i2c_init(struct rcar_i2c_priv *priv) { /* reset master mode */ @@ -170,7 +211,7 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv) static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) { - int i; + int i, ret; for (i = 0; i < LOOP_TIMEOUT; i++) { /* make sure that bus is not busy */ @@ -179,7 +220,15 @@ static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) udelay(1); } - return -EBUSY; + /* Waiting did not help, try to recover */ + priv->recovery_icmcr = MDBS | OBPC | FSDA | FSCL; + ret = i2c_recover_bus(&priv->adap); + + /* No failure when recovering, so check bus busy bit again */ + if (ret == 0) + ret = (rcar_i2c_read(priv, ICMCR) & FSDA) ? -EBUSY : 0; + + return ret; } static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, struct i2c_timings *t) @@ -851,6 +900,7 @@ static int rcar_i2c_probe(struct platform_device *pdev) adap->retries = 3; adap->dev.parent = dev; adap->dev.of_node = dev->of_node; + adap->bus_recovery_info = &rcar_i2c_bri; i2c_set_adapdata(adap, priv); strlcpy(adap->name, pdev->name, sizeof(adap->name));