staging:iio:ad7793: Fix temperature scale and offset

[firefly-linux-kernel-4.4.55.git] / drivers / staging / iio / adc / ad7793.c

diff --git a/drivers/staging/iio/adc/ad7793.c b/drivers/staging/iio/adc/ad7793.c
index 76fdd7145fc5d855544c977560dfc3803baa7b95..3c8d1d4c6192c1d1c0f1fe3d2a0e899372e2ad1f 100644 (file)
--- a/drivers/staging/iio/adc/ad7793.c
+++ b/drivers/staging/iio/adc/ad7793.c
@@ -604,9 +604,6 @@ static int ad7793_read_raw(struct iio_dev *indio_dev,
                *val = (smpl >> chan->scan_type.shift) &
                        ((1 << (chan->scan_type.realbits)) - 1);
 
-               if (!unipolar)
-                       *val -= (1 << (chan->scan_type.realbits - 1));
-
                return IIO_VAL_INT;
 
        case IIO_CHAN_INFO_SCALE:
@@ -620,25 +617,38 @@ static int ad7793_read_raw(struct iio_dev *indio_dev,
                                return IIO_VAL_INT_PLUS_NANO;
                        } else {
                                /* 1170mV / 2^23 * 6 */
-                               scale_uv = (1170ULL * 100000000ULL * 6ULL)
-                                       >> (chan->scan_type.realbits -
-                                           (unipolar ? 0 : 1));
+                               scale_uv = (1170ULL * 100000000ULL * 6ULL);
                        }
                        break;
                case IIO_TEMP:
-                       /* Always uses unity gain and internal ref */
-                       scale_uv = (2500ULL * 100000000ULL)
-                               >> (chan->scan_type.realbits -
-                               (unipolar ? 0 : 1));
+                               /* 1170mV / 0.81 mV/C / 2^23 */
+                               scale_uv = 1444444444444ULL;
                        break;
                default:
                        return -EINVAL;
                }
 
-               *val2 = do_div(scale_uv, 100000000) * 10;
-               *val =  scale_uv;
-
+               scale_uv >>= (chan->scan_type.realbits - (unipolar ? 0 : 1));
+               *val = 0;
+               *val2 = scale_uv;
                return IIO_VAL_INT_PLUS_NANO;
+       case IIO_CHAN_INFO_OFFSET:
+               if (!unipolar)
+                       *val = -(1 << (chan->scan_type.realbits - 1));
+               else
+                       *val = 0;
+
+               /* Kelvin to Celsius */
+               if (chan->type == IIO_TEMP) {
+                       unsigned long long offset;
+                       unsigned int shift;
+
+                       shift = chan->scan_type.realbits - (unipolar ? 0 : 1);
+                       offset = 273ULL << shift;
+                       do_div(offset, 1444);
+                       *val -= offset;
+               }
+               return IIO_VAL_INT;
        }
        return -EINVAL;
 }
@@ -676,7 +686,7 @@ static int ad7793_write_raw(struct iio_dev *indio_dev,
                                }
                                ret = 0;
                        }
-
+               break;
        default:
                ret = -EINVAL;
        }
@@ -720,9 +730,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 0,
                        .address = AD7793_CH_AIN1P_AIN1M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 0,
-                       .scan_type = IIO_ST('s', 24, 32, 0)
+                       .scan_type = IIO_ST('u', 24, 32, 0)
                },
                .channel[1] = {
                        .type = IIO_VOLTAGE,
@@ -732,9 +743,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 1,
                        .address = AD7793_CH_AIN2P_AIN2M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 1,
-                       .scan_type = IIO_ST('s', 24, 32, 0)
+                       .scan_type = IIO_ST('u', 24, 32, 0)
                },
                .channel[2] = {
                        .type = IIO_VOLTAGE,
@@ -744,9 +756,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 2,
                        .address = AD7793_CH_AIN3P_AIN3M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 2,
-                       .scan_type = IIO_ST('s', 24, 32, 0)
+                       .scan_type = IIO_ST('u', 24, 32, 0)
                },
                .channel[3] = {
                        .type = IIO_VOLTAGE,
@@ -757,9 +770,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 2,
                        .address = AD7793_CH_AIN1M_AIN1M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 3,
-                       .scan_type = IIO_ST('s', 24, 32, 0)
+                       .scan_type = IIO_ST('u', 24, 32, 0)
                },
                .channel[4] = {
                        .type = IIO_TEMP,
@@ -769,7 +783,7 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
                        IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
                        .scan_index = 4,
-                       .scan_type = IIO_ST('s', 24, 32, 0),
+                       .scan_type = IIO_ST('u', 24, 32, 0),
                },
                .channel[5] = {
                        .type = IIO_VOLTAGE,
@@ -778,9 +792,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel = 4,
                        .address = AD7793_CH_AVDD_MONITOR,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
+                       IIO_CHAN_INFO_SCALE_SEPARATE_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 5,
-                       .scan_type = IIO_ST('s', 24, 32, 0),
+                       .scan_type = IIO_ST('u', 24, 32, 0),
                },
                .channel[6] = IIO_CHAN_SOFT_TIMESTAMP(6),
        },
@@ -793,9 +808,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 0,
                        .address = AD7793_CH_AIN1P_AIN1M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 0,
-                       .scan_type = IIO_ST('s', 16, 32, 0)
+                       .scan_type = IIO_ST('u', 16, 32, 0)
                },
                .channel[1] = {
                        .type = IIO_VOLTAGE,
@@ -805,9 +821,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 1,
                        .address = AD7793_CH_AIN2P_AIN2M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 1,
-                       .scan_type = IIO_ST('s', 16, 32, 0)
+                       .scan_type = IIO_ST('u', 16, 32, 0)
                },
                .channel[2] = {
                        .type = IIO_VOLTAGE,
@@ -817,9 +834,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 2,
                        .address = AD7793_CH_AIN3P_AIN3M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 2,
-                       .scan_type = IIO_ST('s', 16, 32, 0)
+                       .scan_type = IIO_ST('u', 16, 32, 0)
                },
                .channel[3] = {
                        .type = IIO_VOLTAGE,
@@ -830,9 +848,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel2 = 2,
                        .address = AD7793_CH_AIN1M_AIN1M,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                       IIO_CHAN_INFO_SCALE_SHARED_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 3,
-                       .scan_type = IIO_ST('s', 16, 32, 0)
+                       .scan_type = IIO_ST('u', 16, 32, 0)
                },
                .channel[4] = {
                        .type = IIO_TEMP,
@@ -842,7 +861,7 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
                        IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
                        .scan_index = 4,
-                       .scan_type = IIO_ST('s', 16, 32, 0),
+                       .scan_type = IIO_ST('u', 16, 32, 0),
                },
                .channel[5] = {
                        .type = IIO_VOLTAGE,
@@ -851,9 +870,10 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
                        .channel = 4,
                        .address = AD7793_CH_AVDD_MONITOR,
                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
-                       IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
+                       IIO_CHAN_INFO_SCALE_SEPARATE_BIT |
+                       IIO_CHAN_INFO_OFFSET_SHARED_BIT,
                        .scan_index = 5,
-                       .scan_type = IIO_ST('s', 16, 32, 0),
+                       .scan_type = IIO_ST('u', 16, 32, 0),
                },
                .channel[6] = IIO_CHAN_SOFT_TIMESTAMP(6),
        },