hwmon: (occ) Fix poll rate limiting

The poll rate limiter time was initialized at zero. This breaks the
comparison in time_after if jiffies is large. Switch to storing the
next update time rather than the previous time, and initialize the
time when the device is probed.

Fixes: c10e753d43eb ("hwmon (occ): Add sensor types and versions")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20210429151336.18980-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
index f1ac153..967532a 100644 (file)
--- a/drivers/hwmon/occ/common.c
+++ b/drivers/hwmon/occ/common.c
@@ -217,9 +217,9 @@ int occ_update_response(struct occ *occ)
                return rc;
 
        /* limit the maximum rate of polling the OCC */
-       if (time_after(jiffies, occ->last_update + OCC_UPDATE_FREQUENCY)) {
+       if (time_after(jiffies, occ->next_update)) {
                rc = occ_poll(occ);
-               occ->last_update = jiffies;
+               occ->next_update = jiffies + OCC_UPDATE_FREQUENCY;
        } else {
                rc = occ->last_error;
        }
@@ -1165,6 +1165,7 @@ int occ_setup(struct occ *occ, const char *name)
                return rc;
        }
 
+       occ->next_update = jiffies + OCC_UPDATE_FREQUENCY;
        occ_parse_poll_response(occ);
 
        rc = occ_setup_sensor_attrs(occ);

diff --git a/drivers/hwmon/occ/common.h b/drivers/hwmon/occ/common.h
index 67e6968..e6df719 100644 (file)
--- a/drivers/hwmon/occ/common.h
+++ b/drivers/hwmon/occ/common.h
@@ -99,7 +99,7 @@ struct occ {
        u8 poll_cmd_data;               /* to perform OCC poll command */
        int (*send_cmd)(struct occ *occ, u8 *cmd);
 
-       unsigned long last_update;
+       unsigned long next_update;
        struct mutex lock;              /* lock OCC access */
 
        struct device *hwmon;