Re: [v2] hwmon: (scpi) skip unsupported sensors properly

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Oct 28, 2015 at 05:17:31PM +0000, Sudeep Holla wrote:
> 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
> 
> 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: Guenter Roeck <linux@roeck-us.net>
> Reviewed-by: Punit Agrawal <punit.agrawal@arm.com>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> Acked-by: Guenter Roeck <linux@roeck-us.net>

In the assumption that this patch can now be applied, I queued it up
for the next -rc.

Guenter

> ---
>  drivers/hwmon/scpi-hwmon.c | 21 +++++++++++----------
>  1 file changed, 11 insertions(+), 10 deletions(-)
> 
> Hi Guenter,
> 
> Either me/Punit will need ping you once the original driver is merged
> via arm-soc so that you can pick this after that. Alternatively we
> can push it via arm-soc but I wouldn't rush for that as it's not that
> urgent. Is that fine with you ?
> 
> Regards,
> Sudeep
> 
> --
> 1.9.1
> 
> diff --git a/drivers/hwmon/scpi-hwmon.c b/drivers/hwmon/scpi-hwmon.c
> index 2c1241bbf9af..7e20567bc369 100644
> --- a/drivers/hwmon/scpi-hwmon.c
> +++ b/drivers/hwmon/scpi-hwmon.c
> @@ -117,7 +117,7 @@ static int scpi_hwmon_probe(struct platform_device *pdev)
>  	struct scpi_ops *scpi_ops;
>  	struct device *hwdev, *dev = &pdev->dev;
>  	struct scpi_sensors *scpi_sensors;
> -	int ret;
> +	int ret, idx;
> 
>  	scpi_ops = get_scpi_ops();
>  	if (!scpi_ops)
> @@ -146,8 +146,8 @@ static int scpi_hwmon_probe(struct platform_device *pdev)
> 
>  	scpi_sensors->scpi_ops = scpi_ops;
> 
> -	for (i = 0; i < nr_sensors; i++) {
> -		struct sensor_data *sensor = &scpi_sensors->data[i];
> +	for (i = 0, idx = 0; i < nr_sensors; i++) {
> +		struct sensor_data *sensor = &scpi_sensors->data[idx];
> 
>  		ret = scpi_ops->sensor_get_info(i, &sensor->info);
>  		if (ret)
> @@ -183,7 +183,7 @@ static int scpi_hwmon_probe(struct platform_device *pdev)
>  			num_power++;
>  			break;
>  		default:
> -			break;
> +			continue;
>  		}
> 
>  		sensor->dev_attr_input.attr.mode = S_IRUGO;
> @@ -194,11 +194,12 @@ static int scpi_hwmon_probe(struct platform_device *pdev)
>  		sensor->dev_attr_label.show = scpi_show_label;
>  		sensor->dev_attr_label.attr.name = sensor->label;
> 
> -		scpi_sensors->attrs[i << 1] = &sensor->dev_attr_input.attr;
> -		scpi_sensors->attrs[(i << 1) + 1] = &sensor->dev_attr_label.attr;
> +		scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
> +		scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
> 
> -		sysfs_attr_init(scpi_sensors->attrs[i << 1]);
> -		sysfs_attr_init(scpi_sensors->attrs[(i << 1) + 1]);
> +		sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
> +		sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
> +		idx++;
>  	}
> 
>  	scpi_sensors->group.attrs = scpi_sensors->attrs;
> @@ -236,8 +237,8 @@ static int scpi_hwmon_probe(struct platform_device *pdev)
> 
>  		zone->sensor_id = i;
>  		zone->scpi_sensors = scpi_sensors;
> -		zone->tzd = thermal_zone_of_sensor_register(dev, i, zone,
> -							    &scpi_sensor_ops);
> +		zone->tzd = thermal_zone_of_sensor_register(dev,
> +				sensor->info.sensor_id, zone, &scpi_sensor_ops);
>  		/*
>  		 * The call to thermal_zone_of_sensor_register returns
>  		 * an error for sensors that are not associated with