From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758227AbaHZNvW (ORCPT ); Tue, 26 Aug 2014 09:51:22 -0400 Received: from mail.active-venture.com ([67.228.131.205]:53363 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757781AbaHZNvU (ORCPT ); Tue, 26 Aug 2014 09:51:20 -0400 X-Originating-IP: 108.223.40.66 Message-ID: <53FC90D6.9000603@roeck-us.net> Date: Tue, 26 Aug 2014 06:51:18 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Chanwoo Choi , Jonghwa Lee CC: linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org, jdelvare@suse.de Subject: Re: [PATCH] hwmon: ntc_thermistor: Add ntc thermistor to thermal subsystem as a sensor. References: <1409031220-25922-1-git-send-email-jonghwa3.lee@samsung.com> <53FC5D7B.4040506@samsung.com> In-Reply-To: <53FC5D7B.4040506@samsung.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/26/2014 03:12 AM, Chanwoo Choi wrote: > Hi Jonghwa, > > On 08/26/2014 02:33 PM, Jonghwa Lee wrote: >> To get more comprehensive and integrated thermal management, it adds ntc >> thermistor to thermal framework as a thermal sensor. It's governed thermal >> susbsystem only if it is described in DT node. Otherwise, it just notifies >> temperature to userspace via sysfs as it used to be. >> >> Signed-off-by: Jonghwa Lee >> --- >> .../devicetree/bindings/hwmon/ntc_thermistor.txt | 3 +++ >> drivers/hwmon/ntc_thermistor.c | 26 ++++++++++++++++++++ >> 2 files changed, 29 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt b/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt >> index 2391e5c..fcca8e7 100644 >> --- a/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt >> +++ b/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt >> @@ -25,6 +25,9 @@ Requires node properties: >> - "io-channels" Channel node of ADC to be used for >> conversion. >> >> +Optional node properties: >> +- "#thermal-sensor-cells" Used to expose itself to thermal fw. >> + >> Read more about iio bindings at >> Documentation/devicetree/bindings/iio/iio-bindings.txt >> >> diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c >> index bd41072..369dc8c 100644 >> --- a/drivers/hwmon/ntc_thermistor.c >> +++ b/drivers/hwmon/ntc_thermistor.c >> @@ -38,6 +38,7 @@ >> >> #include >> #include >> +#include >> >> struct ntc_compensation { >> int temp_c; >> @@ -182,6 +183,7 @@ struct ntc_data { >> struct device *dev; >> int n_comp; >> char name[PLATFORM_NAME_SIZE]; >> + struct thermal_zone_device *tz; >> }; >> >> #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO) >> @@ -428,6 +430,20 @@ static int ntc_thermistor_get_ohm(struct ntc_data *data) >> return -EINVAL; >> } >> >> +static int ntc_read_temp(void *dev, long *temp) >> +{ >> + struct ntc_data *data = dev_get_drvdata(dev); >> + int ohm; >> + >> + ohm = ntc_thermistor_get_ohm(data); >> + if (ohm < 0) >> + return ohm; >> + >> + *temp = get_temp_mc(data, ohm); >> + >> + return 0; >> +} >> + >> static ssize_t ntc_show_name(struct device *dev, >> struct device_attribute *attr, char *buf) >> { >> @@ -562,6 +578,13 @@ static int ntc_thermistor_probe(struct platform_device *pdev) >> dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n", >> pdev_id->name); >> >> + data->tz = thermal_zone_of_sensor_register(data->dev, 0, data->dev, >> + ntc_read_temp, NULL); >> + if (IS_ERR(data->tz)) { >> + dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n"); >> + data->tz = NULL; >> + } >> + >> return 0; >> err_after_sysfs: >> sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); >> @@ -578,6 +601,9 @@ static int ntc_thermistor_remove(struct platform_device *pdev) >> sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); >> ntc_iio_channel_release(pdata); >> >> + if (data->tz) >> + thermal_zone_of_sensor_unregister(data->dev, data->tz); > > thermal_zone_of_sensor_unregister just return without operation if data->tz is NULL. > So, don't need to check the value of data->tz with if statement. > On a side note, devm_thermal_zone_of_sensor_register would be quite useful to have. Guenter