Add FIFO and hwfifo handling. Add some functions to deal with FIFO
entries and configuration. This feature will be needed for e.g.
watermark setting.
Signed-off-by: Lothar Rubusch <l.rubusch@xxxxxxxxx>
---
drivers/iio/accel/adxl345_core.c | 38 ++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index b917b02245..f686037df3 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -420,6 +420,41 @@ static int adxl345_get_status(struct adxl34x_state *st, u8 *int_stat)
return 0;
}
+static int adxl345_push_fifo_data(struct iio_dev *indio_dev,
+ u8 status,
+ int fifo_entries)
+{
+ struct adxl34x_state *st = iio_priv(indio_dev);
+ int ndirs = 3; /* 3 directions */
+ int i, ret;
+
+ if (fifo_entries <= 0)
+ return true;
+
+ ret = adxl345_read_fifo_elements(st, fifo_entries);
+ if (ret)
+ return false;
+
+ for (i = 0; i < ndirs * fifo_entries; i += ndirs) {
+ /* To ensure that the FIFO has completely popped, there must be at least 5
+ * us between the end of reading the data registers, signified by the
+ * transition to register 0x38 from 0x37 or the CS pin going high, and the
+ * start of new reads of the FIFO or reading the FIFO_STATUS register. For
+ * SPI operation at 1.5 MHz or lower, the register addressing portion of the
+ * transmission is sufficient delay to ensure the FIFO has completely
+ * popped. It is necessary for SPI operation greater than 1.5 MHz to
+ * de-assert the CS pin to ensure a total of 5 us, which is at most 3.4 us
+ * at 5 MHz operation.
+ */
+ if (st->fifo_delay && (fifo_entries > 1))
+ udelay(3);
+
+ iio_push_to_buffers(indio_dev, &st->fifo_buf[i]);
+ }
+
+ return true;
+}
+
/* data ready trigger */
static int adxl345_trig_dready(struct iio_trigger *trig, bool state)
@@ -492,6 +527,9 @@ static irqreturn_t adxl345_trigger_handler(int irq, void *p)
if (adxl345_get_fifo_entries(st, &fifo_entries) < 0)
goto err;
+ if (adxl345_push_fifo_data(indio_dev, int_stat, fifo_entries) < 0)
+ goto err;
+
iio_trigger_notify_done(indio_dev->trig);
}
--
2.39.2
