Re: [lm-sensors] [PATCH] hwmon: (scpi) skip unsupported sensors properly

From: Sudeep Holla <sudeep.holla@arm.com>
To: Punit Agrawal <punit.agrawal@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
	linux-kernel@vger.kernel.org, Guenter Roeck <linux@roeck-us.net>,
	lm-sensors@lm-sensors.org, Jean Delvare <jdelvare@suse.com>
Subject: Re: [lm-sensors] [PATCH] hwmon: (scpi) skip unsupported sensors properly
Date: Wed, 28 Oct 2015 15:58:47 +0000	[thread overview]
Message-ID: <5630F0B7.6010702@arm.com> (raw)
In-Reply-To: <9hhio5rato2.fsf@e105922-lin.cambridge.arm.com>

On 28/10/15 15:39, Punit Agrawal wrote:
> Hi Sudeep,
>
> Sudeep Holla <sudeep.holla@arm.com> writes:
>
>> Currently it's assumed that firmware exports only the class of sensors
>> supported by the driver. However with newer firmware or SCPI protocol
>> revision, support for newer classes of sensors can be present.
>>
>> The driver fails to probe with the following warning if an unsupported
>> class of sensor is encountered in the firmware.
>>
>> sysfs: cannot create duplicate filename
>> 	'/devices/platform/scpi/scpi:sensors/hwmon/hwmon0/'
>> ------------[ cut here ]------------
>> WARNING: at fs/sysfs/dir.c:31
>> Modules linked in:
>>
>> CPU: 0 PID: 6 Comm: kworker/u12:0 Not tainted 4.3.0-rc7 #137
>> Hardware name: ARM Juno development board (r0) (DT)
>> Workqueue: deferwq deferred_probe_work_func
>> PC is at sysfs_warn_dup+0x54/0x78
>> LR is at sysfs_warn_dup+0x54/0x78
>>
>
> Thanks for spotting the issue and the fix below. Some comments below.
>
>
>> This patch fixes the above issue by skipping through the unsupported
>> class of SCPI sensors.
>>
>> Fixes: 68acc77a2d51 ("hwmon: Support thermal zones registration for SCP temperature sensors")
>> Fixes: ea98b29a05e9 ("hwmon: Support sensors exported via ARM SCP interface")
>> Cc: Punit Agrawal <punit.agrawal@arm.com>
>> Cc: Guenter Roeck <linux@roeck-us.net>
>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
>
>
>> ---
>>   drivers/hwmon/scpi-hwmon.c | 21 +++++++++++----------
>>   1 file changed, 11 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/hwmon/scpi-hwmon.c b/drivers/hwmon/scpi-hwmon.c
>> index 2c1241bbf9af..5b80cd7f5c86 100644
>> --- a/drivers/hwmon/scpi-hwmon.c
>> +++ b/drivers/hwmon/scpi-hwmon.c
>
> [...]
>
>> @@ -234,9 +235,9 @@ static int scpi_hwmon_probe(struct platform_device *pdev)
>>   			goto unregister_tzd;
>>   		}
>>
>> -		zone->sensor_id = i;
>> +		zone->sensor_id = sensor->info.sensor_id;
>
> This shouldn't be changed . The zone->sensor_id is used to access the sensor
> data in scpi_read_temp and will use the wrong index with the above
> change. Which means...
>

Ah, right thanks for spotting this.

>>   		zone->scpi_sensors = scpi_sensors;
>> -		zone->tzd = thermal_zone_of_sensor_register(dev, i, zone,
>> +		zone->tzd = thermal_zone_of_sensor_register(dev, zone->sensor_id, zone,
>>   							    &scpi_sensor_ops);
>
> ... the thermal zone registration should use sensor->info.sensor_id
> instead of zone->sensor_id.
>
> With these two changes, feel free to add
>
>       Reviewed-by: Punit Agrawal <punit.agrawal@arm.com>

Will update the patch with these 2 changes and resend. Thanks for the
review.

-- 
Regards,
Sudeep

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