From patchwork Mon Jun 15 15:49:55 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vaibhav Hiremath X-Patchwork-Id: 6610311 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 8954B9F326 for ; Mon, 15 Jun 2015 16:00:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9121620719 for ; Mon, 15 Jun 2015 16:00:30 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8A94B2070E for ; Mon, 15 Jun 2015 16:00:29 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z4Wle-0003M5-Ir; Mon, 15 Jun 2015 15:57:46 +0000 Received: from mail-pa0-f48.google.com ([209.85.220.48]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z4Wi5-000086-Cd for linux-arm-kernel@lists.infradead.org; Mon, 15 Jun 2015 15:54:06 +0000 Received: by pacgb13 with SMTP id gb13so37932919pac.1 for ; Mon, 15 Jun 2015 08:53:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=6DNoCMDLg9hLljIWWBxxvavsZo8cSMC0dW4te05MUU0=; b=QgEw3yDWrSfpM5Vh5sLXB3pQCRoSv8rFniSIT72+aeqyOEjesuhgg741u7YuQHpJGG fHTsy0Nt4wDloQaJe2/6e8XspALhMacDcDNEltxiZc15N3nQDlLgnEb0CVI/w2ibMJwZ S0QiP+MbuSoh1tMzwMGjmfsdAWe+ERekQLbG/Qf7jpc8H39v8xlIz9egtm3fScBwxjLz icbLzD34qs0WPKTsY1D4ceNQZdtP9Fl6OyF7jLczmaiGZGM1qYS4CVMPyHpBBm2ZKgvv xnDeoRWu9FKsPQsqhVubKNwy0qZIYF9UAtUmjgsOR0ukV3AYAiz+F11ta+uGoxU/CVX0 yMZA== X-Gm-Message-State: ALoCoQlw2ZGhHIGqMVgeyYrQNz5YKxPQMYwnplFbFixtIh66hosRCtN5ZpovWjKLohHOfMelnRJN X-Received: by 10.68.231.98 with SMTP id tf2mr50184973pbc.12.1434383624146; Mon, 15 Jun 2015 08:53:44 -0700 (PDT) Received: from localhost.localdomain ([202.62.77.106]) by mx.google.com with ESMTPSA id fs16sm12662484pdb.12.2015.06.15.08.53.40 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 15 Jun 2015 08:53:43 -0700 (PDT) From: Vaibhav Hiremath To: linux-i2c@vger.kernel.org Subject: [PATCH-V2 08/12] i2c: pxa: enable/disable i2c module across msg xfer Date: Mon, 15 Jun 2015 21:19:55 +0530 Message-Id: <1434383399-2370-9-git-send-email-vaibhav.hiremath@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1434383399-2370-1-git-send-email-vaibhav.hiremath@linaro.org> References: <1434383399-2370-1-git-send-email-vaibhav.hiremath@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150615_085405_512874_BF2AFCE0 X-CRM114-Status: GOOD ( 15.93 ) X-Spam-Score: -0.7 (/) Cc: Yi Zhang , robert.jarzmik@free.fr, Vaibhav Hiremath , linux-arm-kernel@lists.infradead.org, wsa@the-dreams.de X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Yi Zhang Enable i2c module/unit before transmission and disable when it finishes. why? It's because the i2c bus may be distrubed if the slave device, typically a touch, powers on. As we do not want to break slave mode support, this patch introduces DT property to control disable of the I2C module after xfer in master mode of operation. i2c-disable-after-xfer : If set, driver will disable I2C module after msg xfer Signed-off-by: Yi Zhang Signed-off-by: Vaibhav Hiremath --- drivers/i2c/busses/i2c-pxa.c | 41 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c index 0a8b3bb..c753411 100644 --- a/drivers/i2c/busses/i2c-pxa.c +++ b/drivers/i2c/busses/i2c-pxa.c @@ -161,6 +161,7 @@ struct pxa_i2c { unsigned char master_code; unsigned long rate; bool highmode_enter; + bool disable_after_xfer; }; #define _IBMR(i2c) ((i2c)->reg_ibmr) @@ -286,6 +287,22 @@ static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why) static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret); static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id); +/* enable/disable i2c unit */ +static inline int i2c_pxa_is_enabled(struct pxa_i2c *i2c) +{ + return (readl(_ICR(i2c)) & ICR_IUE); +} + +static inline void i2c_pxa_enable(struct pxa_i2c *i2c, bool enable) +{ + if (enable && !i2c_pxa_is_enabled(i2c)) { + writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c)); + udelay(100); + } else { + writel(readl(_ICR(i2c)) & ~ICR_IUE, _ICR(i2c)); + } +} + static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c) { return !(readl(_ICR(i2c)) & ICR_SCLE); @@ -482,8 +499,7 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c) i2c_pxa_set_slave(i2c, 0); /* enable unit */ - writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c)); - udelay(100); + i2c_pxa_enable(i2c, true); } @@ -840,6 +856,9 @@ static int i2c_pxa_pio_xfer(struct i2c_adapter *adap, struct pxa_i2c *i2c = adap->algo_data; int ret, i; + /* Enable i2c unit */ + i2c_pxa_enable(i2c, true); + /* If the I2C controller is disabled we need to reset it (probably due to a suspend/resume destroying state). We do this here as we can then avoid worrying about resuming the @@ -860,6 +879,11 @@ static int i2c_pxa_pio_xfer(struct i2c_adapter *adap, ret = -EREMOTEIO; out: i2c_pxa_set_slave(i2c, ret); + + /* disable i2c unit */ + if (i2c->disable_after_xfer) + i2c_pxa_enable(i2c, false); + return ret; } @@ -1075,6 +1099,9 @@ static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num struct pxa_i2c *i2c = adap->algo_data; int ret, i; + /* Enable i2c unit */ + i2c_pxa_enable(i2c, true); + for (i = adap->retries; i >= 0; i--) { ret = i2c_pxa_do_xfer(i2c, msgs, num); if (ret != I2C_RETRY) @@ -1088,6 +1115,10 @@ static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num ret = -EREMOTEIO; out: i2c_pxa_set_slave(i2c, ret); + /* disable i2c unit */ + if (i2c->disable_after_xfer) + i2c_pxa_enable(i2c, false); + return ret; } @@ -1128,6 +1159,9 @@ static int i2c_pxa_probe_dt(struct platform_device *pdev, struct pxa_i2c *i2c, /* For device tree we always use the dynamic or alias-assigned ID */ i2c->adap.nr = -1; + i2c->disable_after_xfer = of_property_read_bool(np, + "i2c-disable-after-xfer"); + if (of_get_property(np, "mrvl,i2c-polling", NULL)) i2c->use_pio = 1; if (of_get_property(np, "mrvl,i2c-fast-mode", NULL)) @@ -1278,6 +1312,9 @@ static int i2c_pxa_probe(struct platform_device *dev) platform_set_drvdata(dev, i2c); + if (i2c->disable_after_xfer) + i2c_pxa_enable(i2c, false); + #ifdef CONFIG_I2C_PXA_SLAVE dev_info(&i2c->adap.dev, " PXA I2C adapter, slave address %d\n", i2c->slave_addr);