On 30/03/2023 11:49, Mikko Perttunen wrote:
From: Mikko Perttunen <mperttunen@xxxxxxxxxx>
Thermal zones located in power domains may not be accessible when
the domain is powergated. In this situation, reading the temperature
will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
use -256C as the temperature for offline zones.
For smooth operation, for offline zones, return -EAGAIN when reading
the temperature and allow registration of zones even if they are
offline during probe.
I think it makes more sense to check if the power domain associated with
the device is powered up and if not return -EPROBE_DEFER.
Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
---
v2:
* Adjusted commit message.
* Patch 2/2 dropped for now since it is more controversial,
and this patch is more critical.
drivers/thermal/tegra/tegra-bpmp-thermal.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/thermal/tegra/tegra-bpmp-thermal.c b/drivers/thermal/tegra/tegra-bpmp-thermal.c
index f5fd4018f72f..4ffc3bb3bf35 100644
--- a/drivers/thermal/tegra/tegra-bpmp-thermal.c
+++ b/drivers/thermal/tegra/tegra-bpmp-thermal.c
@@ -52,6 +52,8 @@ static int __tegra_bpmp_thermal_get_temp(struct tegra_bpmp_thermal_zone *zone,
err = tegra_bpmp_transfer(zone->tegra->bpmp, &msg);
if (err)
return err;
+ if (msg.rx.ret == -BPMP_EFAULT)
+ return -EAGAIN;
if (msg.rx.ret)
return -EINVAL;
@@ -259,7 +261,12 @@ static int tegra_bpmp_thermal_probe(struct platform_device *pdev)
zone->tegra = tegra;
err = __tegra_bpmp_thermal_get_temp(zone, &temp);
- if (err < 0) {
+
+ /*
+ * Sensors in powergated domains may temporarily fail to be read
+ * (-EAGAIN), but will become accessible when the domain is powered on.
+ */
+ if (err < 0 && err != -EAGAIN) {
devm_kfree(&pdev->dev, zone);
continue;
}
--
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