linux-hwmon.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH 1/1] hwmon (occ): Add temp sensor value check
@ 2019-04-17 11:26 Alexander Amelkin
  2019-04-17 13:03 ` Guenter Roeck
  0 siblings, 1 reply; 6+ messages in thread
From: Alexander Amelkin @ 2019-04-17 11:26 UTC (permalink / raw)
  To: linux-hwmon
  Cc: openbmc, Alexander Soldatov, Alexander Amelkin, Edward A . James,
	Joel Stanley

From: Alexander Soldatov <a.soldatov@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 occured, 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.

Signed-off-by: Alexander Soldatov <a.soldatov@yadro.com>
Signed-off-by: Alexander Amelkin <a.amelkin@yadro.com>
Reviewed-by: Alexander Amelkin <a.amelkin@yadro.com>
Cc: Edward A. James <eajames@us.ibm.com>
Cc: Joel Stanley <joel@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 +235,10 @@ static ssize_t occ_show_temp_1(struct device *dev,
 		val = get_unaligned_be16(&temp->sensor_id);
 		break;
 	case 1:
+		/* If a sensor timed out long enough,
+		   OCC returns 0xFFFF for that sensor.*/
+		if (temp->value == 0xFFFF)
+			return -EREMOTEIO;
 		val = get_unaligned_be16(&temp->value) * 1000;
 		break;
 	default:
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2019-04-17 19:36 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-17 11:26 [PATCH 1/1] hwmon (occ): Add temp sensor value check Alexander Amelkin
2019-04-17 13:03 ` Guenter Roeck
2019-04-17 17:46   ` Alexander Amelkin
2019-04-17 18:03     ` [PATCH v2 " Alexander Amelkin
2019-04-17 18:35       ` Eddie James
2019-04-17 19:36         ` Guenter Roeck

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).