From patchwork Fri Jun 24 00:28:26 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 9196237 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B7AF96075A for ; Fri, 24 Jun 2016 00:29:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A5B1528483 for ; Fri, 24 Jun 2016 00:29:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9A05F28484; Fri, 24 Jun 2016 00:29:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 27CC92844B for ; Fri, 24 Jun 2016 00:29:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752009AbcFXA26 (ORCPT ); Thu, 23 Jun 2016 20:28:58 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:34841 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750907AbcFXA24 (ORCPT ); Thu, 23 Jun 2016 20:28:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=roeck-us.net; s=default; h=References:In-Reply-To:Message-Id:Date:Subject: Cc:To:From; bh=VfBuHtmjsvfiabjF0guKdle7/Srf7QgKCG7SwnSSPGc=; b=ymT2tEcZC/IKVw 8nIXiQa5XdcWQsNMNgq0sk0gHeBjGIhddHZYl8GWWPbEqkctDUuH/Tqx55zKjfiq9UkTMn+R0qmjA 7Yqc5CVmL37TMewsIncSRKpiESVjVtAg2w2GLXR7r8KupiUXuPgeUpOKgaib6rdoOYKuHev9k9h6y FsBr0n+zTC9WMnfWXlqLqq7/v6TJtUavL49klIBOBEAr3RsbVN7eOvF/gwHU9tQRxUMSU3Ist69m+ CPLFDIaSbKRMfjZMvqzW+8nOdMZExSRYABDxBeR0eyIUxAf9t4tYYeF3etRMyocOZXHIAKmfPO1gE W402/uaTL8uEoHdY6vmg==; Received: from 108-223-40-66.lightspeed.sntcca.sbcglobal.net ([108.223.40.66]:56282 helo=localhost) by bh-25.webhostbox.net with esmtpa (Exim 4.86_1) (envelope-from ) id 1bGEzE-002KDw-6j; Fri, 24 Jun 2016 00:28:44 +0000 From: Guenter Roeck To: Jean Delvare Cc: Nishanth Menon , linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, Guenter Roeck Subject: [PATCH 3/5] hwmon: (tmp102) Improve handling of initial read delay Date: Thu, 23 Jun 2016 17:28:26 -0700 Message-Id: <1466728108-2512-3-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1466728108-2512-1-git-send-email-linux@roeck-us.net> References: <1466728108-2512-1-git-send-email-linux@roeck-us.net> X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-hwmon-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If the chip was in shutdown mode when the driver was loaded, the first conversion is ready no more than 35 milli-seconds after the chip was taken out of shutdown. The driver delay was so far set to 333 ms (HZ / 3), which is much higher than the maximum time needed by the chip. Reduce the time to 35 milli-seconds. Instead of returning -EAGAIN if data is not yet available, go to sleep for the remaining time. Introduce a 'valid' flag to ensure that sensor data is actually read even if requested less than 333 ms after the driver was loaded. Signed-off-by: Guenter Roeck --- drivers/hwmon/tmp102.c | 44 ++++++++++++++++++++++++++++---------------- 1 file changed, 28 insertions(+), 16 deletions(-) diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c index 5bdf262e6a0e..615f9c176aaf 100644 --- a/drivers/hwmon/tmp102.c +++ b/drivers/hwmon/tmp102.c @@ -13,6 +13,7 @@ * GNU General Public License for more details. */ +#include #include #include #include @@ -46,13 +47,16 @@ #define TMP102_TLOW_REG 0x02 #define TMP102_THIGH_REG 0x03 +#define CONVERSION_TIME_MS 35 /* in milli-seconds */ + struct tmp102 { struct i2c_client *client; struct mutex lock; u16 config_orig; unsigned long last_update; + unsigned long ready_time; + bool valid; int temp[3]; - bool first_time; }; /* convert left adjusted 13-bit TMP102 register value to milliCelsius */ @@ -78,8 +82,16 @@ static struct tmp102 *tmp102_update_device(struct device *dev) struct tmp102 *tmp102 = dev_get_drvdata(dev); struct i2c_client *client = tmp102->client; + /* Is it too early to return a conversion ? */ + if (time_before(jiffies, tmp102->ready_time)) { + unsigned long sleeptime = tmp102->ready_time - jiffies; + + msleep(jiffies_to_msecs(sleeptime)); + } + mutex_lock(&tmp102->lock); - if (time_after(jiffies, tmp102->last_update + HZ / 3)) { + if (!tmp102->valid || + time_after(jiffies, tmp102->last_update + HZ / 3)) { int i; for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) { int status = i2c_smbus_read_word_swapped(client, @@ -88,7 +100,7 @@ static struct tmp102 *tmp102_update_device(struct device *dev) tmp102->temp[i] = tmp102_reg_to_mC(status); } tmp102->last_update = jiffies; - tmp102->first_time = false; + tmp102->valid = true; } mutex_unlock(&tmp102->lock); return tmp102; @@ -98,12 +110,6 @@ static int tmp102_read_temp(void *dev, int *temp) { struct tmp102 *tmp102 = tmp102_update_device(dev); - /* Is it too early even to return a conversion? */ - if (tmp102->first_time) { - dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__); - return -EAGAIN; - } - *temp = tmp102->temp[0]; return 0; @@ -116,10 +122,6 @@ static ssize_t tmp102_show_temp(struct device *dev, struct sensor_device_attribute *sda = to_sensor_dev_attr(attr); struct tmp102 *tmp102 = tmp102_update_device(dev); - /* Is it too early even to return a read? */ - if (tmp102->first_time) - return -EAGAIN; - return sprintf(buf, "%d\n", tmp102->temp[sda->index]); } @@ -224,11 +226,18 @@ static int tmp102_probe(struct i2c_client *client, dev_err(dev, "config settings did not stick\n"); return -ENODEV; } - tmp102->last_update = jiffies; - /* Mark that we are not ready with data until conversion is complete */ - tmp102->first_time = true; + mutex_init(&tmp102->lock); + tmp102->ready_time = jiffies; + if (tmp102->config_orig & TMP102_CONF_SD) { + /* + * Mark that we are not ready with data until the first + * conversion is complete + */ + tmp102->ready_time += msecs_to_jiffies(CONVERSION_TIME_MS); + } + hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, tmp102, tmp102_groups); @@ -261,12 +270,15 @@ static int tmp102_suspend(struct device *dev) static int tmp102_resume(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); + struct tmp102 *tmp102 = i2c_get_clientdata(client); int config; config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG); if (config < 0) return config; + tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS); + config &= ~TMP102_CONF_SD; return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config); }