[PATCH v2 1/1] hwmon (occ): Add temp sensor value check

[Guenter Roeck]

On Wed, Apr 17, 2019 at 01:35:41PM -0500, Eddie James wrote:
> 
> On 4/17/19 1:03 PM, Alexander Amelkin wrote:
> >From: Alexander Soldatov <a.soldatov at yadro.com>
> >
> >The occ driver supports two formats for the temp sensor value.
> >
> >The OCC firmware for P8 supports only the first format, for which
> >no range checking or error processing is performed in the driver.
> >Inspecting the OCC sources for P8 reveals that OCC may send
> >a special value 0xFFFF to indicate that a sensor read timeout
> >has occurred, see
> >
> >https://github.com/open-power/occ/blob/master_p8/src/occ/cmdh/cmdh_fsp_cmds.c#L395
> >
> >That situation wasn't handled in the driver. This patch adds invalid
> >temp value check for the sensor data format 1 and handles it the same
> >way as it is done for the format 2, where EREMOTEIO is reported for
> >this case.
> 
> 
> Thanks Alexander and Guenter.
> 
> 
> Reviewed-by: Eddie James <eajames at linux.ibm.com>
> 

Applied.

Thanks,
Guenter

> 
> >
> >Signed-off-by: Alexander Soldatov <a.soldatov at yadro.com>
> >Signed-off-by: Alexander Amelkin <a.amelkin at yadro.com>
> >Reviewed-by: Alexander Amelkin <a.amelkin at yadro.com>
> >Cc: Edward A. James <eajames at us.ibm.com>
> >Cc: Joel Stanley <joel at jms.id.au>
> >---
> >  drivers/hwmon/occ/common.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> >diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
> >index 4679acb..825631c 100644
> >--- a/drivers/hwmon/occ/common.c
> >+++ b/drivers/hwmon/occ/common.c
> >@@ -235,6 +235,12 @@ static ssize_t occ_show_temp_1(struct device *dev,
> >  		val = get_unaligned_be16(&temp->sensor_id);
> >  		break;
> >  	case 1:
> >+		/*
> >+		 * If a sensor reading has expired and couldn't be refreshed,
> >+		 * OCC returns 0xFFFF for that sensor.
> >+		 */
> >+		if (temp->value == 0xFFFF)
> >+			return -EREMOTEIO;
> >  		val = get_unaligned_be16(&temp->value) * 1000;
> >  		break;
> >  	default:
>