From patchwork Tue Jul 21 12:41:03 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vaibhav Hiremath X-Patchwork-Id: 6835721 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 77B959F358 for ; Tue, 21 Jul 2015 12:48:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7D0072064B for ; Tue, 21 Jul 2015 12:48:50 +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 9214920648 for ; Tue, 21 Jul 2015 12:48:49 +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 1ZHWwZ-0007HB-4T; Tue, 21 Jul 2015 12:46:47 +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 1ZHWwH-000796-Ki for linux-arm-kernel@lists.infradead.org; Tue, 21 Jul 2015 12:46:30 +0000 Received: by pdrg1 with SMTP id g1so120231215pdr.2 for ; Tue, 21 Jul 2015 05:46:08 -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=xbOyUboWm8QxFnMsi0/XkHNlhcsH2C2MUu3fJJ0O2ls=; b=kLq5+yU6kg5XDGb3/PoqjQQRumZslfnKpm6vKHRMOs0J1iCh8S+VTh6qohAnZ8GWcv cvMtTXDA7MpQm/fpqDgz2YPQqws1B5yoKTrMperyfRYhPt7bpIXm982SQ66+V3uGBFA7 Rm5Pi3MUuBKz1HxJWuPw9DqWM4mqRXOZNgIFpiv2by1PdDvxf7acY78rgRpbY3601k/3 eKjJzh3XWuL2Y2GyCJO6tJubp82Oq/5orzu8+TKpXd5w33CgWXAR1TgDjFMqqyANDI+P v4nGlwR7KBgqkvxvW9dfCj/M3I3IwqHPwtTxQXwhCFVvc5G8unU6NUYWvHjxCJH3T071 5YlQ== X-Gm-Message-State: ALoCoQlXA8J9U2gQKJ1bMn+SvhLHNxKqr2LwqDu5uhdjxSbruBbXi2AgwaEIqCeDiM3yEzZbHQHH X-Received: by 10.66.146.226 with SMTP id tf2mr73895729pab.4.1437482768689; Tue, 21 Jul 2015 05:46:08 -0700 (PDT) Received: from localhost.localdomain ([202.62.77.106]) by smtp.gmail.com with ESMTPSA id f4sm27378854pdc.95.2015.07.21.05.46.03 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 21 Jul 2015 05:46:07 -0700 (PDT) From: Vaibhav Hiremath To: linux-arm-kernel@lists.infradead.org Subject: [PATCH-v5 2/5] i2c: pxa: enable/disable i2c module across msg xfer Date: Tue, 21 Jul 2015 18:11:03 +0530 Message-Id: <1437482466-16126-3-git-send-email-vaibhav.hiremath@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1437482466-16126-1-git-send-email-vaibhav.hiremath@linaro.org> References: <1437482466-16126-1-git-send-email-vaibhav.hiremath@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150721_054629_729808_5D9A6BC3 X-CRM114-Status: GOOD ( 17.66 ) 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 , linux-i2c@vger.kernel.org, robert.jarzmik@free.fr 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=-5.4 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 disturbed 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 66cf437..abf04f2 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)) @@ -1264,6 +1300,9 @@ 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);