[PATCH] iio: pressure: dps310: don't wait for new temperature in trigger handler

[PATCH] iio: pressure: dps310: don't wait for new temperature in trigger handler

[Rupesh Majhi]

Each scan waits for a new temperature result before reading pressure.
With pressure sampled faster than temperature, scans then come at the
temperature rate: an 8 Hz trigger with temperature at its default 1 Hz
gives one scan a second.

Read pressure first and take the latest temperature, as a direct
pressure read already does. Wait for temperature only when pressure is
not in the scan.

Fixes: 9b7cad9ce2ed ("iio: pressure: dps310: add triggered buffer support")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20261110154254.39092-1-zoone.rupert%40gmail.com
Signed-off-by: Rupesh Majhi <zoone.rupert@gmail.com>
---
 drivers/iio/pressure/dps310.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c
index 85df58ac1809..c4d779f8bbc6 100644
--- a/drivers/iio/pressure/dps310.c
+++ b/drivers/iio/pressure/dps310.c
@@ -910,10 +910,18 @@ static int dps310_fill_channels(struct dps310_data *data,
 	unsigned int i;
 	int rc;
 
-	/* Compensation needs a temperature, so it is sampled either way */
-	rc = dps310_read_temp_raw_locked(data);
-	if (rc)
-		return rc;
+	if (test_bit(DPS310_SCAN_PRESSURE, scan_mask)) {
+		rc = dps310_read_pres_raw_locked(data);
+		if (rc)
+			return rc;
+
+		/* Waiting here would hold scans to the temperature rate */
+		dps310_refresh_temp_locked(data);
+	} else {
+		rc = dps310_read_temp_raw_locked(data);
+		if (rc)
+			return rc;
+	}
 
 	i = 0;
 	if (test_bit(DPS310_SCAN_TEMP, scan_mask)) {
@@ -924,10 +932,6 @@ static int dps310_fill_channels(struct dps310_data *data,
 	}
 
 	if (test_bit(DPS310_SCAN_PRESSURE, scan_mask)) {
-		rc = dps310_read_pres_raw_locked(data);
-		if (rc)
-			return rc;
-
 		/* Pascals, see the channel definition */
 		rc = dps310_calculate_pressure(data, &channels[i++]);
 		if (rc)

base-commit: 79c8dffd84e9784ec05bea68dbe5e71f7ec9941a
-- 
2.43.0

Re: [PATCH] iio: pressure: dps310: don't wait for new temperature in trigger handler

[Arnav Kapoor]

On Wed, Nov 11, 2026 at 09:51:18PM +0200, Rupesh Majhi wrote:
> +	if (test_bit(DPS310_SCAN_PRESSURE, scan_mask)) {
> +		rc = dps310_read_pres_raw_locked(data);
> +		if (rc)
> +			return rc;
> +
> +		/* Waiting here would hold scans to the temperature rate */
> +		dps310_refresh_temp_locked(data);

Maybe I'm getting this wrong, but isn't there a case the new path
doesn't cover? Nothing reads a temperature at probe, so if a pressure
only buffer is enabled shortly after probe and the first pressure
result is ready before any temperature result,
dps310_refresh_temp_locked() finds TMP_RDY clear and the pressure is
compensated with temp_raw still 0.

I think the FIFO path handles this case by dps310_fifo_hold() keeping
pressure entries until fifo_temp_valid is set by the first
temperature. Would it make sense to do the same here with a flag set
when a temperature has been read, and wait for one temperature in
dps310_refresh_temp_locked() only while it's unset? That would cover
direct pressure reads and after the first sample the scans stay at the
pressure rate as your patch intends.

Thanks,
Arnav