On 2/8/23 12:31, Thierry Reding wrote:
On Tue, Feb 07, 2023 at 03:56:08PM +0200, 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 and the temperature is considered to be
-256C for calculating trips.
Where's that -256C being set? I only see THERMAL_TEMP_INVALID being set
as the default for a zone, but that's not -274C, not -256C. If that's
the temperature that you're referring to, it might be better to state
that we rely on the default temperature rather than any specific number.
Thierry
It is based on BPMP's internal behavior.
Mikko
For smooth operation, for offline zones, return -EAGAIN when reading
the temperature and allow registration of zones even if they are
offline during probe.
Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
---
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 c76e1ea62c8a..628b18818ae9 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;
@@ -257,7 +259,12 @@ 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;
}
--
2.39.0
