From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756628AbbLAPKD (ORCPT ); Tue, 1 Dec 2015 10:10:03 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:46187 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756237AbbLAPKA (ORCPT ); Tue, 1 Dec 2015 10:10:00 -0500 Subject: Re: [PATCH] hwmon: (tmp102) Force wait for conversion time for the first valid data To: Nishanth Menon , Jean Delvare References: <1448943955-2385-1-git-send-email-nm@ti.com> <565D3513.7050905@roeck-us.net> <565DA504.4060600@ti.com> <20151201142152.GA10891@ogun.home> Cc: linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org, linux-omap@vger.kernel.org, beagleboard-x15@googlegroups.com, Eduardo Valentin From: Guenter Roeck Message-ID: <565DB845.4050709@roeck-us.net> Date: Tue, 1 Dec 2015 07:09:57 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <20151201142152.GA10891@ogun.home> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@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: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/01/2015 06:21 AM, Nishanth Menon wrote: [ ... ] > > Hint about how the patch will look like: Looks ok (and better). Guenter > diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c > index 65482624ea2c..5289aa0980a8 100644 > --- a/drivers/hwmon/tmp102.c > +++ b/drivers/hwmon/tmp102.c > @@ -58,6 +58,7 @@ struct tmp102 { > u16 config_orig; > unsigned long last_update; > int temp[3]; > + bool first_time; > }; > > /* convert left adjusted 13-bit TMP102 register value to milliCelsius */ > @@ -93,6 +94,7 @@ 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; > } > mutex_unlock(&tmp102->lock); > return tmp102; > @@ -102,6 +104,12 @@ 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; > @@ -114,6 +122,10 @@ 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]); > } > > @@ -207,7 +219,9 @@ static int tmp102_probe(struct i2c_client *client, > status = -ENODEV; > goto fail_restore_config; > } > - tmp102->last_update = jiffies - HZ; > + tmp102->last_update = jiffies; > + /* Mark that we are not ready with data until conversion is complete */ > + tmp102->first_time = true; > mutex_init(&tmp102->lock); > > hwmon_dev = hwmon_device_register_with_groups(dev, client->name, >