From patchwork Fri Oct 24 06:50:15 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wenyou Yang X-Patchwork-Id: 5144491 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 [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 658AD9F374 for ; Fri, 24 Oct 2014 07:32:07 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7C5012018E for ; Fri, 24 Oct 2014 07:32:06 +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 93D902010F for ; Fri, 24 Oct 2014 07:32:05 +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 1XhYlZ-0004Yg-CH; Fri, 24 Oct 2014 06:54:29 +0000 Received: from eusmtp01.atmel.com ([212.144.249.242]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XhYlW-0004W3-BI for linux-arm-kernel@lists.infradead.org; Fri, 24 Oct 2014 06:54:27 +0000 Received: from apsmtp01.atmel.com (10.168.254.31) by eusmtp01.atmel.com (10.161.101.30) with Microsoft SMTP Server id 14.2.347.0; Fri, 24 Oct 2014 08:53:58 +0200 Received: from shaarm01.corp.atmel.com (10.168.254.13) by apsmtp01.atmel.com (10.168.254.31) with Microsoft SMTP Server id 14.2.347.0; Fri, 24 Oct 2014 14:54:38 +0800 From: Wenyou Yang To: , Subject: [PATCH v3 1/3] i2c/at91: add support for runtime PM Date: Fri, 24 Oct 2014 14:50:15 +0800 Message-ID: <1414133417-11530-2-git-send-email-wenyou.yang@atmel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1414133417-11530-1-git-send-email-wenyou.yang@atmel.com> References: <1414133417-11530-1-git-send-email-wenyou.yang@atmel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141023_235426_723405_8FDB0AC2 X-CRM114-Status: GOOD ( 13.91 ) X-Spam-Score: -1.4 (-) Cc: khilman@kernel.org, nicolas.ferre@atmel.com, linux-kernel@vger.kernel.org, wenyou.yang@atmel.com, linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, 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 Drivers should put the device into low power states proactively whenever the device is not in use. Thus implement support for runtime PM and use the autosuspend feature to make sure that we can still perform well in case we see lots of i2c traffic within short period of time. Signed-off-by: Wenyou Yang --- drivers/i2c/busses/i2c-at91.c | 38 ++++++++++++++++++++++++++++++++------ 1 file changed, 32 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c index 917d545..a25fb5e 100644 --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -31,10 +31,12 @@ #include #include #include +#include #define DEFAULT_TWI_CLK_HZ 100000 /* max 400 Kbits/s */ #define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */ #define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */ +#define AUTOSUSPEND_TIMEOUT 2000 /* AT91 TWI register definitions */ #define AT91_TWI_CR 0x0000 /* Control Register */ @@ -481,6 +483,10 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num) dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num); + ret = pm_runtime_get_sync(dev->dev); + if (ret < 0) + goto out; + /* * The hardware can handle at most two messages concatenated by a * repeated start via it's internal address feature. @@ -488,18 +494,21 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num) if (num > 2) { dev_err(dev->dev, "cannot handle more than two concatenated messages.\n"); - return 0; + ret = 0; + goto out; } else if (num == 2) { int internal_address = 0; int i; if (msg->flags & I2C_M_RD) { dev_err(dev->dev, "first transfer must be write.\n"); - return -EINVAL; + ret = -EINVAL; + goto out; } if (msg->len > 3) { dev_err(dev->dev, "first message size must be <= 3.\n"); - return -EINVAL; + ret = -EINVAL; + goto out; } /* 1st msg is put into the internal address, start with 2nd */ @@ -523,7 +532,12 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num) ret = at91_do_twi_transfer(dev); - return (ret < 0) ? ret : num; + ret = (ret < 0) ? ret : num; +out: + pm_runtime_mark_last_busy(dev->dev); + pm_runtime_put_autosuspend(dev->dev); + + return ret; } static u32 at91_twi_func(struct i2c_adapter *adapter) @@ -795,11 +809,20 @@ static int at91_twi_probe(struct platform_device *pdev) dev->adapter.timeout = AT91_I2C_TIMEOUT; dev->adapter.dev.of_node = pdev->dev.of_node; + pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT); + pm_runtime_use_autosuspend(dev->dev); + pm_runtime_set_active(dev->dev); + pm_runtime_enable(dev->dev); + rc = i2c_add_numbered_adapter(&dev->adapter); if (rc) { dev_err(dev->dev, "Adapter %s registration failed\n", dev->adapter.name); clk_disable_unprepare(dev->clk); + + pm_runtime_disable(dev->dev); + pm_runtime_set_suspended(dev->dev); + return rc; } @@ -814,6 +837,9 @@ static int at91_twi_remove(struct platform_device *pdev) i2c_del_adapter(&dev->adapter); clk_disable_unprepare(dev->clk); + pm_runtime_disable(dev->dev); + pm_runtime_set_suspended(dev->dev); + return 0; } @@ -823,7 +849,7 @@ static int at91_twi_runtime_suspend(struct device *dev) { struct at91_twi_dev *twi_dev = dev_get_drvdata(dev); - clk_disable(twi_dev->clk); + clk_disable_unprepare(twi_dev->clk); return 0; } @@ -832,7 +858,7 @@ static int at91_twi_runtime_resume(struct device *dev) { struct at91_twi_dev *twi_dev = dev_get_drvdata(dev); - return clk_enable(twi_dev->clk); + return clk_prepare_enable(twi_dev->clk); } static const struct dev_pm_ops at91_twi_pm = {