iio: imu: bmi270: add temperature channel

The BMI270 IMU includes a temperature sensor. Add a channel for reading
the temperature.

Signed-off-by: Gustavo Silva <gustavograzs@gmail.com>
Link: https://patch.msgid.link/20250118-bmi270-temp-v2-1-50bc85f36ab2@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/imu/bmi270/bmi270_core.c b/drivers/iio/imu/bmi270/bmi270_core.c
index 7fec52e0b48624f07031b63a9caf6c318f33f5dc..464dcdd657c4ba27fdb7620c80e9f05e2a831910 100644 (file)
--- a/drivers/iio/imu/bmi270/bmi270_core.c
+++ b/drivers/iio/imu/bmi270/bmi270_core.c
@@ -5,6 +5,7 @@
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
+#include <linux/units.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -28,10 +29,11 @@
 #define BMI270_INTERNAL_STATUS_REG                     0x21
 #define BMI270_INTERNAL_STATUS_MSG_MSK                 GENMASK(3, 0)
 #define BMI270_INTERNAL_STATUS_MSG_INIT_OK             0x01
-
 #define BMI270_INTERNAL_STATUS_AXES_REMAP_ERR_MSK      BIT(5)
 #define BMI270_INTERNAL_STATUS_ODR_50HZ_ERR_MSK                BIT(6)
 
+#define BMI270_TEMPERATURE_0_REG                       0x22
+
 #define BMI270_ACC_CONF_REG                            0x40
 #define BMI270_ACC_CONF_ODR_MSK                                GENMASK(3, 0)
 #define BMI270_ACC_CONF_ODR_100HZ                      0x08
@@ -69,6 +71,10 @@
 #define BMI270_PWR_CTRL_ACCEL_EN_MSK                   BIT(2)
 #define BMI270_PWR_CTRL_TEMP_EN_MSK                    BIT(3)
 
+/* See datasheet section 4.6.14, Temperature Sensor */
+#define BMI270_TEMP_OFFSET                             11776
+#define BMI270_TEMP_SCALE                              1953125
+
 #define BMI260_INIT_DATA_FILE "bmi260-init-data.fw"
 #define BMI270_INIT_DATA_FILE "bmi270-init-data.fw"
 
@@ -109,6 +115,7 @@ EXPORT_SYMBOL_NS_GPL(bmi270_chip_info, "IIO_BMI270");
 enum bmi270_sensor_type {
        BMI270_ACCEL    = 0,
        BMI270_GYRO,
+       BMI270_TEMP,
 };
 
 struct bmi270_scale {
@@ -136,6 +143,10 @@ static const struct bmi270_scale bmi270_gyro_scale[] = {
        { 0, 66 },
 };
 
+static const struct bmi270_scale bmi270_temp_scale[] = {
+       { BMI270_TEMP_SCALE / MICRO, BMI270_TEMP_SCALE % MICRO },
+};
+
 struct bmi270_scale_item {
        const struct bmi270_scale *tbl;
        int num;
@@ -150,6 +161,10 @@ static const struct bmi270_scale_item bmi270_scale_table[] = {
                .tbl    = bmi270_gyro_scale,
                .num    = ARRAY_SIZE(bmi270_gyro_scale),
        },
+       [BMI270_TEMP] = {
+               .tbl    = bmi270_temp_scale,
+               .num    = ARRAY_SIZE(bmi270_temp_scale),
+       },
 };
 
 static const struct bmi270_odr bmi270_accel_odr[] = {
@@ -255,7 +270,7 @@ static int bmi270_set_scale(struct bmi270_data *data, int chan_type, int uscale)
 }
 
 static int bmi270_get_scale(struct bmi270_data *bmi270_device, int chan_type,
-                           int *uscale)
+                           int *scale, int *uscale)
 {
        int ret;
        unsigned int val;
@@ -280,6 +295,10 @@ static int bmi270_get_scale(struct bmi270_data *bmi270_device, int chan_type,
                val = FIELD_GET(BMI270_GYR_CONF_RANGE_MSK, val);
                bmi270_scale_item = bmi270_scale_table[BMI270_GYRO];
                break;
+       case IIO_TEMP:
+               val = 0;
+               bmi270_scale_item = bmi270_scale_table[BMI270_TEMP];
+               break;
        default:
                return -EINVAL;
        }
@@ -287,6 +306,7 @@ static int bmi270_get_scale(struct bmi270_data *bmi270_device, int chan_type,
        if (val >= bmi270_scale_item.num)
                return -EINVAL;
 
+       *scale = bmi270_scale_item.tbl[val].scale;
        *uscale = bmi270_scale_item.tbl[val].uscale;
        return 0;
 }
@@ -399,6 +419,9 @@ static int bmi270_get_data(struct bmi270_data *bmi270_device,
        case IIO_ANGL_VEL:
                reg = BMI270_ANG_VEL_X_REG + (axis - IIO_MOD_X) * 2;
                break;
+       case IIO_TEMP:
+               reg = BMI270_TEMPERATURE_0_REG;
+               break;
        default:
                return -EINVAL;
        }
@@ -427,9 +450,16 @@ static int bmi270_read_raw(struct iio_dev *indio_dev,
 
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
-               *val = 0;
-               ret = bmi270_get_scale(bmi270_device, chan->type, val2);
+               ret = bmi270_get_scale(bmi270_device, chan->type, val, val2);
                return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
+       case IIO_CHAN_INFO_OFFSET:
+               switch (chan->type) {
+               case IIO_TEMP:
+                       *val = BMI270_TEMP_OFFSET;
+                       return IIO_VAL_INT;
+               default:
+                       return -EINVAL;
+               }
        case IIO_CHAN_INFO_SAMP_FREQ:
                ret = bmi270_get_odr(bmi270_device, chan->type, val, val2);
                return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
@@ -544,6 +574,13 @@ static const struct iio_chan_spec bmi270_channels[] = {
        BMI270_ANG_VEL_CHANNEL(X),
        BMI270_ANG_VEL_CHANNEL(Y),
        BMI270_ANG_VEL_CHANNEL(Z),
+       {
+               .type = IIO_TEMP,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                                     BIT(IIO_CHAN_INFO_SCALE) |
+                                     BIT(IIO_CHAN_INFO_OFFSET),
+               .scan_index = -1, /* No buffer support */
+       },
        IIO_CHAN_SOFT_TIMESTAMP(BMI270_SCAN_TIMESTAMP),
 };
 
@@ -646,7 +683,8 @@ static int bmi270_configure_imu(struct bmi270_data *bmi270_device)
        ret = regmap_set_bits(regmap, BMI270_PWR_CTRL_REG,
                              BMI270_PWR_CTRL_AUX_EN_MSK |
                              BMI270_PWR_CTRL_GYR_EN_MSK |
-                             BMI270_PWR_CTRL_ACCEL_EN_MSK);
+                             BMI270_PWR_CTRL_ACCEL_EN_MSK |
+                             BMI270_PWR_CTRL_TEMP_EN_MSK);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to enable accelerometer and gyroscope");