Patch "iio: adc: ti-ads1015: fix scale information for ADS1115" has been added to the 4.9-stable tree

Patch "iio: adc: ti-ads1015: fix scale information for ADS1115" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: adc: ti-ads1015: fix scale information for ADS1115

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iio-adc-ti-ads1015-fix-scale-information-for-ads1115.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 8d0e8e795623bd6229cf48bb7777a1c456c370ed Mon Sep 17 00:00:00 2001
From: Akinobu Mita <akinobu.mita@gmail.com>
Date: Fri, 21 Jul 2017 00:24:18 +0900
Subject: iio: adc: ti-ads1015: fix scale information for ADS1115

From: Akinobu Mita <akinobu.mita@gmail.com>

commit 8d0e8e795623bd6229cf48bb7777a1c456c370ed upstream.

The ti-ads1015 driver supports ADS1015 and ADS1115 devices.  The same
scale information is used for both devices in this driver, however they
have actually different values and the ADS1115's one is not correct.

These devices have the same full-scale input voltage range for each PGA
selection.  So instead of adding another hardcoded scale information,
compute a correct scale on demand from each device's resolution.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iio/adc/ti-ads1015.c |   48 +++++++++++++++++++++----------------------
 1 file changed, 24 insertions(+), 24 deletions(-)

--- a/drivers/iio/adc/ti-ads1015.c
+++ b/drivers/iio/adc/ti-ads1015.c
@@ -80,18 +80,12 @@ static const unsigned int ads1115_data_r
 	8, 16, 32, 64, 128, 250, 475, 860
 };
 
-static const struct {
-	int scale;
-	int uscale;
-} ads1015_scale[] = {
-	{3, 0},
-	{2, 0},
-	{1, 0},
-	{0, 500000},
-	{0, 250000},
-	{0, 125000},
-	{0, 125000},
-	{0, 125000},
+/*
+ * Translation from PGA bits to full-scale positive and negative input voltage
+ * range in mV
+ */
+static int ads1015_fullscale_range[] = {
+	6144, 4096, 2048, 1024, 512, 256, 256, 256
 };
 
 #define ADS1015_V_CHAN(_chan, _addr) {				\
@@ -299,17 +293,20 @@ err:
 	return IRQ_HANDLED;
 }
 
-static int ads1015_set_scale(struct ads1015_data *data, int chan,
+static int ads1015_set_scale(struct ads1015_data *data,
+			     struct iio_chan_spec const *chan,
 			     int scale, int uscale)
 {
 	int i, ret, rindex = -1;
+	int fullscale = div_s64((scale * 1000000LL + uscale) <<
+				(chan->scan_type.realbits - 1), 1000000);
 
-	for (i = 0; i < ARRAY_SIZE(ads1015_scale); i++)
-		if (ads1015_scale[i].scale == scale &&
-		    ads1015_scale[i].uscale == uscale) {
+	for (i = 0; i < ARRAY_SIZE(ads1015_fullscale_range); i++) {
+		if (ads1015_fullscale_range[i] == fullscale) {
 			rindex = i;
 			break;
 		}
+	}
 	if (rindex < 0)
 		return -EINVAL;
 
@@ -319,7 +316,7 @@ static int ads1015_set_scale(struct ads1
 	if (ret < 0)
 		return ret;
 
-	data->channel_data[chan].pga = rindex;
+	data->channel_data[chan->address].pga = rindex;
 
 	return 0;
 }
@@ -377,9 +374,9 @@ static int ads1015_read_raw(struct iio_d
 	}
 	case IIO_CHAN_INFO_SCALE:
 		idx = data->channel_data[chan->address].pga;
-		*val = ads1015_scale[idx].scale;
-		*val2 = ads1015_scale[idx].uscale;
-		ret = IIO_VAL_INT_PLUS_MICRO;
+		*val = ads1015_fullscale_range[idx];
+		*val2 = chan->scan_type.realbits - 1;
+		ret = IIO_VAL_FRACTIONAL_LOG2;
 		break;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		idx = data->channel_data[chan->address].data_rate;
@@ -406,7 +403,7 @@ static int ads1015_write_raw(struct iio_
 	mutex_lock(&data->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
-		ret = ads1015_set_scale(data, chan->address, val, val2);
+		ret = ads1015_set_scale(data, chan, val, val2);
 		break;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		ret = ads1015_set_data_rate(data, chan->address, val);
@@ -438,7 +435,10 @@ static const struct iio_buffer_setup_ops
 	.validate_scan_mask = &iio_validate_scan_mask_onehot,
 };
 
-static IIO_CONST_ATTR(scale_available, "3 2 1 0.5 0.25 0.125");
+static IIO_CONST_ATTR_NAMED(ads1015_scale_available, scale_available,
+	"3 2 1 0.5 0.25 0.125");
+static IIO_CONST_ATTR_NAMED(ads1115_scale_available, scale_available,
+	"0.1875 0.125 0.0625 0.03125 0.015625 0.007813");
 
 static IIO_CONST_ATTR_NAMED(ads1015_sampling_frequency_available,
 	sampling_frequency_available, "128 250 490 920 1600 2400 3300");
@@ -446,7 +446,7 @@ static IIO_CONST_ATTR_NAMED(ads1115_samp
 	sampling_frequency_available, "8 16 32 64 128 250 475 860");
 
 static struct attribute *ads1015_attributes[] = {
-	&iio_const_attr_scale_available.dev_attr.attr,
+	&iio_const_attr_ads1015_scale_available.dev_attr.attr,
 	&iio_const_attr_ads1015_sampling_frequency_available.dev_attr.attr,
 	NULL,
 };
@@ -456,7 +456,7 @@ static const struct attribute_group ads1
 };
 
 static struct attribute *ads1115_attributes[] = {
-	&iio_const_attr_scale_available.dev_attr.attr,
+	&iio_const_attr_ads1115_scale_available.dev_attr.attr,
 	&iio_const_attr_ads1115_sampling_frequency_available.dev_attr.attr,
 	NULL,
 };


Patches currently in stable-queue which might be from akinobu.mita@gmail.com are

queue-4.9/iio-adc-ti-ads1015-enable-conversion-when-config_pm-is-not-set.patch
queue-4.9/iio-adc-ti-ads1015-add-adequate-wait-time-to-get-correct-conversion.patch
queue-4.9/iio-adc-ti-ads1015-don-t-return-invalid-value-from-buffer-setup-callbacks.patch
queue-4.9/iio-adc-ti-ads1015-fix-incorrect-data-rate-setting-update.patch
queue-4.9/iio-adc-ti-ads1015-fix-scale-information-for-ads1115.patch
queue-4.9/iio-adc-ti-ads1015-avoid-getting-stale-result-after-runtime-resume.patch