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Groups > linux.kernel > #1728937

[PATCH 4.13 13/47] iio: adc: ti-ads1015: fix scale information for ADS1115

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 4.13 13/47] iio: adc: ti-ads1015: fix scale information for ADS1115
Date 2017-09-08 16:00 +0200
Message-ID <unrZ8-7KT-13@gated-at.bofh.it> (permalink)
References <unrw5-7zK-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

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
@@ -81,18 +81,12 @@ 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) {				\
@@ -300,17 +294,20 @@ 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;
 
@@ -320,7 +317,7 @@ 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;
 }
@@ -378,9 +375,9 @@ 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;
@@ -407,7 +404,7 @@ 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);
@@ -439,7 +436,10 @@ 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");
@@ -447,7 +447,7 @@ 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,
 };
@@ -457,7 +457,7 @@ 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,
 };

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Thread

[PATCH 4.13 00/47] 4.13.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 14/47] iio: adc: ti-ads1015: enable conversion when CONFIG_PM is not set Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 10/47] staging: ccree: save ciphertext for CTS IV Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 24/47] fpga: altera-hps2fpga: fix multiple init of l3_remap_lock Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 12/47] iio: adc: ti-ads1015: fix incorrect data rate setting update Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 42/47] cs5536: add support for IDE controller variant Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 16/47] iio: adc: ti-ads1015: dont return invalid value from buffer setup callbacks Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 33/47] iwlwifi: pci: add new PCI ID for 7265D Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 36/47] MCB: add support for SC31 to mcb-lpc Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 41/47] ahci: dont use MSI for devices with the silly Intel NVMe remapping scheme Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 09/47] staging/rts5208: fix incorrect shift to extract upper nybble Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 35/47] mwifiex: correct channel stat buffer overflows Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 39/47] drm/nouveau: Fix error handling in nv50_disp_atomic_commit Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 01/47] usb: quirks: add delay init quirk for Corsair Strafe RGB keyboard Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 40/47] workqueue: Fix flag collision Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 19/47] HID: wacom: Do not completely map WACOM_HID_WD_TOUCHRINGSTATUS usage Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 18/47] driver core: bus: Fix a potential double free Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:30 +0200
  [PATCH 4.13 37/47] s390/mm: avoid empty zero pages for KVM guests to avoid postcopy hangs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 23/47] thunderbolt: Fix reset response_type Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 25/47] intel_th: pci: Add Cannon Lake PCH-H support Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 44/47] scsi: sg: recheck MMAP_IO request length with lock held Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 46/47] rtlwifi: Fix memory leak when firmware request fails Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 31/47] rtlwifi: rtl_pci_probe: Fix fail path of _rtl_pci_find_adapter Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 28/47] drm/vgem: Pin our pages for dmabuf exports Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 38/47] drm/nouveau/pci/msi: disable MSI on big-endian platforms by default Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 26/47] intel_th: pci: Add Cannon Lake PCH-LP support Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 27/47] ath10k: fix memory leak in rx ring buffer allocation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 47/47] rtlwifi: Fix fallback firmware loading Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 43/47] scsi: sg: protect against races between mmap() and SG_SET_RESERVED_SIZE Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 45/47] of/device: Prevent buffer overflow in of_device_modalias() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 32/47] Bluetooth: Add support of 13d3:3494 RTL8723BE device Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 15:50 +0200
  [PATCH 4.13 20/47] binder: free memory on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 15/47] iio: adc: ti-ads1015: avoid getting stale result after runtime resume Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 03/47] usb: Add device quirk for Logitech HD Pro Webcam C920-C Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 13/47] iio: adc: ti-ads1015: fix scale information for ADS1115 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 08/47] USB: core: Avoid race of async_completed() w/ usbdev_release() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 04/47] usb:xhci:Fix regression when ATI chipsets detected Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 05/47] USB: musb: fix external abort on suspend Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 07/47] ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 17/47] iio: adc: ti-ads1015: add adequate wait time to get correct conversion Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 06/47] ANDROID: binder: add padding to binder_fd_array_object. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  [PATCH 4.13 02/47] USB: serial: option: add support for D-Link DWM-157 C1 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-08 16:00 +0200
  Re: [PATCH 4.13 00/47] 4.13.1-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-09-08 19:00 +0200
    Re: [PATCH 4.13 00/47] 4.13.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-09 07:50 +0200
  Re: [PATCH 4.13 00/47] 4.13.1-stable review Guenter Roeck <linux@roeck-us.net> - 2017-09-09 15:50 +0200
    Re: [PATCH 4.13 00/47] 4.13.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-09 16:20 +0200

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