[PATCH v2 1/3] iio: accel: adxl372: Fix/remove limitation for FIFO samples

From: Stefan Popa <stefan.popa@analog.com>
To: <jic23@kernel.org>
Cc: <Michael.Hennerich@analog.com>, <knaack.h@gmx.de>,
	<lars@metafoo.de>, <pmeerw@pmeerw.net>,
	<linux-kernel@vger.kernel.org>, <linux-iio@vger.kernel.org>,
	<stefan.popa@analog.com>
Subject: [PATCH v2 1/3] iio: accel: adxl372: Fix/remove limitation for FIFO samples
Date: Tue, 10 Sep 2019 17:43:32 +0300	[thread overview]
Message-ID: <1568126612-13134-1-git-send-email-stefan.popa@analog.com> (raw)

Currently, the driver sets the FIFO_SAMPLES register with the number of
sample sets (maximum of 170 for 3 axis data, 256 for 2-axis and 512 for
single axis). However, the FIFO_SAMPLES register should store the number
of samples, regardless of how the FIFO format is configured.

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
---
Changes in v2:
	- st->watermark needs to store the number of sample sets, 
	  the total number of samples is computed in
	  adxl372_configure_fifo() func.

 drivers/iio/accel/adxl372.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c
index 055227cb..7de5e1b 100644
--- a/drivers/iio/accel/adxl372.c
+++ b/drivers/iio/accel/adxl372.c
@@ -474,12 +474,17 @@ static int adxl372_configure_fifo(struct adxl372_state *st)
 	if (ret < 0)
 		return ret;
 
-	fifo_samples = st->watermark & 0xFF;
+	/*
+	 * watermak stores the number of sets; we need to write the FIFO
+	 * registers with the number of samples
+	 */
+	fifo_samples = (st->watermark * st->fifo_set_size);
 	fifo_ctl = ADXL372_FIFO_CTL_FORMAT_MODE(st->fifo_format) |
 		   ADXL372_FIFO_CTL_MODE_MODE(st->fifo_mode) |
-		   ADXL372_FIFO_CTL_SAMPLES_MODE(st->watermark);
+		   ADXL372_FIFO_CTL_SAMPLES_MODE(fifo_samples);
 
-	ret = regmap_write(st->regmap, ADXL372_FIFO_SAMPLES, fifo_samples);
+	ret = regmap_write(st->regmap,
+			   ADXL372_FIFO_SAMPLES, fifo_samples & 0xFF);
 	if (ret < 0)
 		return ret;
 
-- 
2.7.4

