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From: "Stefan Brüns" <stefan.bruens@rwth-aachen.de>
To: <linux-iio@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>,
	Jonathan Cameron <jic23@kernel.org>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Subject: [PATCH v2 2/4] iio: light: vl6180: Avoid readback of integration time register
Date: Sun, 24 Sep 2017 00:58:22 +0200	[thread overview]
Message-ID: <20170923225824.8435-3-stefan.bruens@rwth-aachen.de> (raw)
In-Reply-To: <20170923225824.8435-1-stefan.bruens@rwth-aachen.de>

Instead of reading the value from the register on each query, store the
set value.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
---
 drivers/iio/light/vl6180.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
index 68b9babfd298..e6466cc81766 100644
--- a/drivers/iio/light/vl6180.c
+++ b/drivers/iio/light/vl6180.c
@@ -86,6 +86,7 @@
 struct vl6180_data {
 	struct i2c_client *client;
 	struct mutex lock;
+	unsigned int als_it_ms;
 };
 
 enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
@@ -306,13 +307,11 @@ static int vl6180_read_raw(struct iio_dev *indio_dev,
 
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_INT_TIME:
-		ret = vl6180_read_word(data->client, VL6180_ALS_IT);
-		if (ret < 0)
-			return ret;
-		*val = 0; /* 1 count = 1ms (0 = 1ms) */
-		*val2 = (ret + 1) * 1000; /* convert to seconds */
+		*val = 0;
+		*val2 = data->als_it_ms * 1000;
 
 		return IIO_VAL_INT_PLUS_MICRO;
+
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_LIGHT:
@@ -401,6 +400,9 @@ static int vl6180_set_it(struct vl6180_data *data, int val, int val2)
 
 	ret = vl6180_write_word(data->client, VL6180_ALS_IT, it_ms - 1);
 
+	if (ret >= 0)
+		data->als_it_ms = it_ms;
+
 fail:
 	vl6180_hold(data, false);
 	mutex_unlock(&data->lock);
@@ -472,6 +474,7 @@ static int vl6180_init(struct vl6180_data *data)
 		return ret;
 
 	/* ALS integration time: 100ms */
+	data->als_it_ms = 100;
 	ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
 	if (ret < 0)
 		return ret;
-- 
2.14.1

  parent reply	other threads:[~2017-09-23 22:59 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-23 22:58 [PATCH v2 0/4] iio: light: vl6180: Several fixes and enhancements Stefan Brüns
2017-09-23 22:58 ` [PATCH v2 1/4] iio: light: vl6180: Move range check to integration time setter, cleanup Stefan Brüns
2017-09-23 22:58 ` Stefan Brüns [this message]
2017-09-23 22:58 ` [PATCH v2 3/4] iio: light: vl6180: Cleanup als_gain lookup, avoid register readback Stefan Brüns
2017-09-23 22:58 ` [PATCH v2 4/4] iio: light: vl6180: Correct ALS scale for non-default gain/integration time Stefan Brüns

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