Guenter Roeck writes: > On 9/3/20 6:47 AM, Lars Povlsen wrote: >> If the temperature is read before the internal calibration is >> completed, the driver returns -EIO. Instead it should return -EAGAIN >> to encourage repeating the operation. >> >> Signed-off-by: Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx> >> --- >> drivers/hwmon/sparx5-temp.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/hwmon/sparx5-temp.c b/drivers/hwmon/sparx5-temp.c >> index 1a2b1026b026..98be48e3a22a 100644 >> --- a/drivers/hwmon/sparx5-temp.c >> +++ b/drivers/hwmon/sparx5-temp.c >> @@ -56,7 +56,7 @@ static int s5_read(struct device *dev, enum hwmon_sensor_types type, >> case hwmon_temp_input: >> stat = readl_relaxed(hwmon->base + TEMP_STAT); >> if (!(stat & TEMP_STAT_VALID)) >> - return -EIO; >> + return -EAGAIN; > > The problem is that this may result in a hard loop and effectively hang the system, > or at least the calling process. It may be better to return -ENODATA in this situation. > Guenther, Thank you for your response. The motivation for the patch was as I tried to use thermal support to control a fan, and I noticed an initial quip from thermal_core.c:update_temperature() - it will throw a dev_warn() for anything else than an "EAGAIN". The EAGAIN also seems to be used by several other hwmon drivers in similar situations. The bottom line is that I would like to get rid of the warning message. Changing the error code to ENODATA does not fix what I am trying to accomplish. Do you have any suggestions on how to achieve the objective? Sincerely, ---Lars > Guenter > >> value = stat & TEMP_STAT_TEMP; >> /* >> * From register documentation: >> -- >> 2.27.0 >> -- Lars Povlsen, Microchip
