4 files changed, 70 insertions, 0 deletions

diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
index 784670e2736b..2ee3ae11eb2a 100644
--- a/drivers/iio/accel/st_accel_core.c
+++ b/drivers/iio/accel/st_accel_core.c
@@ -166,6 +166,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                         .mask_ihl = 0x02,
                         .addr_stat_drdy = ST_SENSORS_DEFAULT_STAT_ADDR,
                 },
+                .sim = {
+                        .addr = 0x23,
+                        .value = BIT(0),
+                },
                 .multi_read_bit = true,
                 .bootime = 2,
         },
@@ -234,6 +238,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                         .mask_od = 0x40,
                         .addr_stat_drdy = ST_SENSORS_DEFAULT_STAT_ADDR,
                 },
+                .sim = {
+                        .addr = 0x23,
+                        .value = BIT(0),
+                },
                 .multi_read_bit = true,
                 .bootime = 2,
         },
@@ -316,6 +324,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                                 .en_mask = 0x08,
                         },
                 },
+                .sim = {
+                        .addr = 0x24,
+                        .value = BIT(0),
+                },
                 .multi_read_bit = false,
                 .bootime = 2,
         },
@@ -379,6 +391,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                         .mask_int1 = 0x04,
                         .addr_stat_drdy = ST_SENSORS_DEFAULT_STAT_ADDR,
                 },
+                .sim = {
+                        .addr = 0x21,
+                        .value = BIT(1),
+                },
                 .multi_read_bit = true,
                 .bootime = 2, /* guess */
         },
@@ -437,6 +453,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                         .mask_od = 0x40,
                         .addr_stat_drdy = ST_SENSORS_DEFAULT_STAT_ADDR,
                 },
+                .sim = {
+                        .addr = 0x21,
+                        .value = BIT(7),
+                },
                 .multi_read_bit = false,
                 .bootime = 2, /* guess */
         },
@@ -499,6 +519,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                         .addr_ihl = 0x22,
                         .mask_ihl = 0x80,
                 },
+                .sim = {
+                        .addr = 0x23,
+                        .value = BIT(0),
+                },
                 .multi_read_bit = true,
                 .bootime = 2,
         },
@@ -547,6 +571,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                         .mask_int1 = 0x04,
                         .addr_stat_drdy = ST_SENSORS_DEFAULT_STAT_ADDR,
                 },
+                .sim = {
+                        .addr = 0x21,
+                        .value = BIT(1),
+                },
                 .multi_read_bit = false,
                 .bootime = 2,
         },
@@ -614,6 +642,10 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
                         .mask_ihl = 0x02,
                         .addr_stat_drdy = ST_SENSORS_DEFAULT_STAT_ADDR,
                 },
+                .sim = {
+                        .addr = 0x23,
+                        .value = BIT(0),
+                },
                 .multi_read_bit = true,
                 .bootime = 2,
         },
diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
index 79c8c7cd70d5..6e6a1ecc99dd 100644
--- a/drivers/iio/common/st_sensors/st_sensors_core.c
+++ b/drivers/iio/common/st_sensors/st_sensors_core.c
@@ -550,6 +550,31 @@ out:
 }
 EXPORT_SYMBOL(st_sensors_read_info_raw);
 
+static int st_sensors_init_interface_mode(struct iio_dev *indio_dev,
+                        const struct st_sensor_settings *sensor_settings)
+{
+        struct st_sensor_data *sdata = iio_priv(indio_dev);
+        struct device_node *np = sdata->dev->of_node;
+        struct st_sensors_platform_data *pdata;
+
+        pdata = (struct st_sensors_platform_data *)sdata->dev->platform_data;
+        if (((np && of_property_read_bool(np, "spi-3wire")) ||
+             (pdata && pdata->spi_3wire)) && sensor_settings->sim.addr) {
+                int err;
+
+                err = sdata->tf->write_byte(&sdata->tb, sdata->dev,
+                                            sensor_settings->sim.addr,
+                                            sensor_settings->sim.value);
+                if (err < 0) {
+                        dev_err(&indio_dev->dev,
+                                "failed to init interface mode\n");
+                        return err;
+                }
+        }
+
+        return 0;
+}
+
 int st_sensors_check_device_support(struct iio_dev *indio_dev,
                         int num_sensors_list,
                         const struct st_sensor_settings *sensor_settings)
@@ -574,6 +599,10 @@ int st_sensors_check_device_support(struct iio_dev *indio_dev,
                 return -ENODEV;
         }
 
+        err = st_sensors_init_interface_mode(indio_dev, &sensor_settings[i]);
+        if (err < 0)
+                return err;
+
         if (sensor_settings[i].wai_addr) {
                 err = sdata->tf->read_byte(&sdata->tb, sdata->dev,
                                            sensor_settings[i].wai_addr, &wai);
diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
index 497f2b3a5a62..97f1b465d04f 100644
--- a/include/linux/iio/common/st_sensors.h
+++ b/include/linux/iio/common/st_sensors.h
@@ -105,6 +105,11 @@ struct st_sensor_fullscale {
         struct st_sensor_fullscale_avl fs_avl[ST_SENSORS_FULLSCALE_AVL_MAX];
 };
 
+struct st_sensor_sim {
+        u8 addr;
+        u8 value;
+};
+
 /**
  * struct st_sensor_bdu - ST sensor device block data update
  * @addr: address of the register.
@@ -197,6 +202,7 @@ struct st_sensor_transfer_function {
  * @bdu: Block data update register.
  * @das: Data Alignment Selection register.
  * @drdy_irq: Data ready register of the sensor.
+ * @sim: SPI serial interface mode register of the sensor.
  * @multi_read_bit: Use or not particular bit for [I2C/SPI] multi-read.
  * @bootime: samples to discard when sensor passing from power-down to power-up.
  */
@@ -213,6 +219,7 @@ struct st_sensor_settings {
         struct st_sensor_bdu bdu;
         struct st_sensor_das das;
         struct st_sensor_data_ready_irq drdy_irq;
+        struct st_sensor_sim sim;
         bool multi_read_bit;
         unsigned int bootime;
 };
diff --git a/include/linux/platform_data/st_sensors_pdata.h b/include/linux/platform_data/st_sensors_pdata.h
index 79b0e4cdb814..f8274b0c6888 100644
--- a/include/linux/platform_data/st_sensors_pdata.h
+++ b/include/linux/platform_data/st_sensors_pdata.h
@@ -17,10 +17,12 @@
  *      Available only for accelerometer and pressure sensors.
  *      Accelerometer DRDY on LSM330 available only on pin 1 (see datasheet).
  * @open_drain: set the interrupt line to be open drain if possible.
+ * @spi_3wire: enable spi-3wire mode.
  */
 struct st_sensors_platform_data {
         u8 drdy_int_pin;
         bool open_drain;
+        bool spi_3wire;
 };
 
 #endif /* ST_SENSORS_PDATA_H */