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[88.193.135.236]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5b9d826fa06sm842860e87.8.2026.09.28.14.11.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Sep 2026 14:11:50 -0700 (PDT) From: Rupesh Majhi To: Andy Shevchenko , David Lechner , Eddie James , Jonathan Cameron , =?UTF-8?q?Nuno=20S=C3=A1?= Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Rupesh Majhi Subject: [PATCH v9 3/3] iio: pressure: dps310: implement .hwfifo_flush_to_buffer() Date: Tue, 29 Sep 2026 00:11:27 +0300 Message-ID: <20260928211127.641828-4-zoone.rupert@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260928211127.641828-1-zoone.rupert@gmail.com> References: <20260928211127.641828-1-zoone.rupert@gmail.com> Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Let userspace drain the FIFO on demand rather than only from the periodic drain. With a trigger attached the FIFO is not running, so there is nothing to flush and the hook returns 0. Hold the mode across the drain, so a concurrent buffer disable cannot free active_scan_mask while it runs. Assisted-by: LLM Signed-off-by: Rupesh Majhi --- drivers/iio/pressure/dps310.c | 36 ++++++++++++++++++++++++++++++++--- 1 file changed, 33 insertions(+), 3 deletions(-) diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c index 66f24adc8df7..2af2971de970 100644 --- a/drivers/iio/pressure/dps310.c +++ b/drivers/iio/pressure/dps310.c @@ -1088,22 +1088,30 @@ static unsigned int dps310_fifo_push_held(struct dps310_data *data) /* * Read the batch out before compensating it, so a pressure entry pairs with - * the temperature preceding it rather than the last one in the batch. + * the temperature preceding it rather than the last one in the batch. Stop + * reading at max_scans rather than after it, since entries leave the hardware + * as they are read and any extra would have to be thrown away. max_scans of + * zero drains everything. * * Returns scans pushed. */ -static int dps310_fifo_drain(struct dps310_data *data) +static int dps310_fifo_drain(struct dps310_data *data, unsigned int max_scans) __must_hold(&data->lock) { bool pressure_enabled = test_bit(DPS310_SCAN_PRESSURE, data->iio->active_scan_mask); u8 kind[DPS310_FIFO_DEPTH]; s32 raw[DPS310_FIFO_DEPTH]; + unsigned int scans = 0; unsigned int pushed = 0; unsigned int cnt, i; + bool is_pressure; int rc; for (cnt = 0; cnt < DPS310_FIFO_DEPTH; cnt++) { + if (max_scans && scans >= max_scans) + break; + rc = dps310_fifo_read_entry(data, &raw[cnt]); if (rc < 0) return rc; @@ -1111,7 +1119,12 @@ static int dps310_fifo_drain(struct dps310_data *data) if (rc == DPS310_FIFO_EMPTY) break; + is_pressure = rc == DPS310_FIFO_PRESSURE; kind[cnt] = rc; + + /* Only the measurement that drives the scans counts */ + if (is_pressure == pressure_enabled) + scans++; } for (i = 0; i < cnt; i++) { @@ -1151,7 +1164,7 @@ static void dps310_fifo_work(struct work_struct *work) int rc; mutex_lock(&data->lock); - rc = dps310_fifo_drain(data); + rc = dps310_fifo_drain(data, 0); mutex_unlock(&data->lock); if (rc < 0) @@ -1186,6 +1199,22 @@ static int dps310_fifo_hold_alloc(struct dps310_data *data, int prs_rate, return 0; } +static int dps310_hwfifo_flush(struct iio_dev *iio, unsigned int count) +{ + struct dps310_data *data = iio_priv(iio); + + /* Holding the mode keeps active_scan_mask alive across the drain */ + IIO_DEV_GUARD_CURRENT_MODE(iio); + + /* A trigger drives the capture instead and leaves the FIFO empty */ + if (iio_device_get_current_mode(iio) != INDIO_BUFFER_SOFTWARE) + return 0; + + guard(mutex)(&data->lock); + + return dps310_fifo_drain(data, count); +} + static int dps310_hwfifo_set_watermark(struct iio_dev *iio, unsigned int val) { struct dps310_data *data = iio_priv(iio); @@ -1327,6 +1356,7 @@ static const struct iio_info dps310_info = { .read_raw = dps310_read_raw, .write_raw = dps310_write_raw, .hwfifo_set_watermark = dps310_hwfifo_set_watermark, + .hwfifo_flush_to_buffer = dps310_hwfifo_flush, }; static int dps310_probe(struct i2c_client *client) -- 2.43.0