From patchwork Mon Jul 6 19:24:51 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vaibhav Hiremath X-Patchwork-Id: 6727461 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 6D6BEC05AC for ; Mon, 6 Jul 2015 19:30:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 73797205F2 for ; Mon, 6 Jul 2015 19:30:36 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8B6A72065D for ; Mon, 6 Jul 2015 19:30:33 +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 1ZCC4Q-0007m1-Kt; Mon, 06 Jul 2015 19:28:50 +0000 Received: from mail-pd0-f170.google.com ([209.85.192.170]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZCC44-0007IB-SQ for linux-arm-kernel@lists.infradead.org; Mon, 06 Jul 2015 19:28:30 +0000 Received: by pdbep18 with SMTP id ep18so110936887pdb.1 for ; Mon, 06 Jul 2015 12:28:08 -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=xWoMnuXCNllbWet9cOcw2OLc6nlUw7+rH2oOa9spUPo=; b=FYZabpH0eekcHQGIk1yPH33EYO6L6JghBSbIhW4qI1gQNwcqetAYSJ29NOp+Wv3LRF dvo9GhWNF0NsX+lcpMk+bySkkwgv2uDzoCjzXuWT5u2bIa72Nzw4X15F4HEHs2J7O0nR tnYR9DAj42z9e2PoLt9+iCcNQgBWFXC+/jNwuvvjH9YTZxYQw5TNSn0t2dS/MxflpG3I 796sZU/mfT6gR+g15sqsvwXn5YUAH65vlrJw9xrp9yZCFhnNCnRsF/vS55Wni5AaneQR iq6yr9omDMzFYsCavMZloXqFbvP93ftBL1Ywwd89TILR3b6HhZumD93ZNzPqz09eyfaX nkhg== X-Gm-Message-State: ALoCoQkgCsbYbcOZeTmZYbAaVEx+M7ySjTAv3xwfGuddn/PqIRTFtEKDvhqkdA8/kb7DdHHaLd3j X-Received: by 10.70.129.204 with SMTP id ny12mr814534pdb.77.1436210888067; Mon, 06 Jul 2015 12:28:08 -0700 (PDT) Received: from localhost.localdomain ([202.62.77.106]) by mx.google.com with ESMTPSA id x7sm19293964pas.28.2015.07.06.12.28.03 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 06 Jul 2015 12:28:06 -0700 (PDT) From: Vaibhav Hiremath To: linux-i2c@vger.kernel.org Subject: [PATCH-v3 07/11] i2c: pxa: enable/disable i2c module across msg xfer Date: Tue, 7 Jul 2015 00:54:51 +0530 Message-Id: <1436210695-19159-8-git-send-email-vaibhav.hiremath@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1436210695-19159-1-git-send-email-vaibhav.hiremath@linaro.org> References: <1436210695-19159-1-git-send-email-vaibhav.hiremath@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150706_122828_947993_44969589 X-CRM114-Status: GOOD ( 17.05 ) X-Spam-Score: -2.6 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, wsa@the-dreams.de, Yi Zhang , linux-kernel@vger.kernel.org, Vaibhav Hiremath , robh+dt@kernel.org, robert.jarzmik@free.fr, linux-arm-kernel@lists.infradead.org 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=-4.9 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 | 43 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 41 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c index 2de9300..dfd1dd0 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) @@ -284,6 +285,24 @@ 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) { + if (!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); @@ -480,8 +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); } @@ -832,6 +850,9 @@ 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 @@ -852,6 +873,11 @@ 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; } @@ -1067,6 +1093,9 @@ 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) @@ -1080,6 +1109,10 @@ 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; } @@ -1120,6 +1153,9 @@ 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)) @@ -1271,6 +1307,9 @@ 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);