linux-kernel - Re: [PATCH 06/16] hwmon: tmp102: expose to thermal fw via DT nodes

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Message-ID: <5238D7D9.9010203@ti.com>
Date:	Tue, 17 Sep 2013 18:29:45 -0400
From:	Eduardo Valentin <eduardo.valentin@...com>
To:	Guenter Roeck <linux@...ck-us.net>
CC:	Eduardo Valentin <eduardo.valentin@...com>,
	<swarren@...dotorg.org>, <pawel.moll@....com>,
	<mark.rutland@....com>, <ian.campbell@...rix.com>,
	<rob.herring@...xeda.com>, <rui.zhang@...el.com>, <wni@...dia.com>,
	<grant.likely@...aro.org>, <durgadoss.r@...el.com>,
	<linux-pm@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<lm-sensors@...sensors.org>, <linux-kernel@...r.kernel.org>,
	Jean Delvare <khali@...ux-fr.org>
Subject: Re: [PATCH 06/16] hwmon: tmp102: expose to thermal fw via DT nodes

On 15-09-2013 19:33, Guenter Roeck wrote:
> On 09/15/2013 03:02 PM, Eduardo Valentin wrote:
>> This patch adds to tmp102 temperature sensor the possibility
>> to expose itself as thermal zone device, registered on the
>> thermal framework.
>>
>> The thermal zone is built only if a device tree node
>> describing a thermal zone for this sensor is present
>> inside the tmp102 DT node. Otherwise, the driver behavior
>> will be the same.
>>
>> Cc: Jean Delvare <khali@...ux-fr.org>
>> Cc: Guenter Roeck <linux@...ck-us.net>
>> Cc: lm-sensors@...sensors.org
>> Cc: linux-kernel@...r.kernel.org
>> Signed-off-by: Eduardo Valentin <eduardo.valentin@...com>
>> ---
>>   drivers/hwmon/tmp102.c | 28 ++++++++++++++++++++++++++++
>>   1 file changed, 28 insertions(+)
>>
>> diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
>> index d7b47ab..e432444 100644
>> --- a/drivers/hwmon/tmp102.c
>> +++ b/drivers/hwmon/tmp102.c
>> @@ -27,6 +27,8 @@
>>   #include <linux/mutex.h>
>>   #include <linux/device.h>
>>   #include <linux/jiffies.h>
>> +#include <linux/thermal.h>
>> +#include <linux/of.h>
>>
>>   #define    DRIVER_NAME "tmp102"
>>
>> @@ -50,6 +52,7 @@
>>
>>   struct tmp102 {
>>       struct device *hwmon_dev;
>> +    struct thermal_zone_device *tz;
>>       struct mutex lock;
>>       u16 config_orig;
>>       unsigned long last_update;
>> @@ -93,6 +96,19 @@ static struct tmp102 *tmp102_update_device(struct
>> i2c_client *client)
>>       return tmp102;
>>   }
>>
>> +static int tmp102_read_temp(void *dev, long *temp)
>> +{
>> +    struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
>> +
>> +    if (tmp102->temp[0] < 0)
>> +        dev_warn(tmp102->hwmon_dev,
>> +             "operating in negative temp: %d\n", tmp102->temp[0]);
>> +
> 
> Please drop this warning.
> 

Done for both drivers.

> Guenter
> 
>> +    *temp = tmp102->temp[0];
>> +
>> +    return 0;
>> +}
>> +
>>   static ssize_t tmp102_show_temp(struct device *dev,
>>                   struct device_attribute *attr,
>>                   char *buf)
>> @@ -204,6 +220,16 @@ static int tmp102_probe(struct i2c_client *client,
>>           goto fail_remove_sysfs;
>>       }
>>
>> +    tmp102->tz = thermal_zone_of_sensor_register(&client->dev, 0,
>> +                             &client->dev,
>> +                             tmp102_read_temp, NULL);
>> +    if (IS_ERR(tmp102->tz)) {
>> +        dev_warn(&client->dev,
>> +             "Could not parse thermal data in device tree: %ld\n",
>> +             PTR_ERR(tmp102->tz));
> 
> Please drop this warning. You already create error messages in
> thermal_zone_of_sensor_register(). That should be sufficient.
> The same applies to the lm75 patch.

OK. Done for both.

> 
> As a side note, I would suggest to provide devm_ functions for
> registration.
> We are introducing those for hwmon registration, which enables us to remove
> most _remove functions. It would be great if we can keep it that way.
> 

Right. This side note is taken. Actually this is on my todo list for
quite a while. But I believe this should not block this series, should
it? I will be probably cleaning the thermal framework code after this
current work is accepted at least.

> On a higher level, I don't think it is a good idea to make thermal zones
> and thermal zone data mandatory. Many systems may neither need nor want it.
> 

Well, I agree with you. Did you see something hard required in the patch
I sent. I made it so that it could continue the driver probe without
thermal zones, as you requested.


I will repost both patches in reply to our thread.

Eduardo

> Guenter
> 
>> +        tmp102->tz = NULL;
>> +    }
>> +
>>       dev_info(&client->dev, "initialized\n");
>>
>>       return 0;
>> @@ -220,6 +246,8 @@ static int tmp102_remove(struct i2c_client *client)
>>   {
>>       struct tmp102 *tmp102 = i2c_get_clientdata(client);
>>
>> +    /* thermal zone life cycle is not our responsibility */
>> +    thermal_zone_of_sensor_unregister(&client->dev, tmp102->tz);
>>       hwmon_device_unregister(tmp102->hwmon_dev);
>>       sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
>>
>>
> 
> 
> 


-- 
You have got to be excited about what you are doing. (L. Lamport)

Eduardo Valentin


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