iio: imu: bmi270: add step counter watermark event

Add support for generating events when the step counter reaches the
configurable watermark.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Gustavo Silva <gustavograzs@gmail.com>
Link: https://patch.msgid.link/20250616-bmi270-events-v3-2-16e37588604f@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 e369151bd713b0256a6b8598d7fe1ba73409bc07..519f1c9d466dceb301b53efee905f1b8fc4468c0 100644 (file)
--- a/drivers/iio/imu/bmi270/bmi270_core.c
+++ b/drivers/iio/imu/bmi270/bmi270_core.c
@@ -8,6 +8,7 @@
 #include <linux/regmap.h>
 #include <linux/units.h>
 
+#include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger.h>
@@ -28,6 +29,9 @@
 #define BMI270_ACCEL_X_REG                             0x0c
 #define BMI270_ANG_VEL_X_REG                           0x12
 
+#define BMI270_INT_STATUS_0_REG                                0x1c
+#define BMI270_INT_STATUS_0_STEP_CNT_MSK               BIT(1)
+
 #define BMI270_INT_STATUS_1_REG                                0x1d
 #define BMI270_INT_STATUS_1_ACC_GYR_DRDY_MSK           GENMASK(7, 6)
 
@@ -74,6 +78,10 @@
 #define BMI270_INT_LATCH_REG                           0x55
 #define BMI270_INT_LATCH_REG_MSK                       BIT(0)
 
+#define BMI270_INT1_MAP_FEAT_REG                       0x56
+#define BMI270_INT2_MAP_FEAT_REG                       0x57
+#define BMI270_INT_MAP_FEAT_STEP_CNT_WTRMRK_MSK                BIT(1)
+
 #define BMI270_INT_MAP_DATA_REG                                0x58
 #define BMI270_INT_MAP_DATA_DRDY_INT1_MSK              BIT(2)
 #define BMI270_INT_MAP_DATA_DRDY_INT2_MSK              BIT(6)
@@ -94,6 +102,7 @@
 #define BMI270_PWR_CTRL_ACCEL_EN_MSK                   BIT(2)
 #define BMI270_PWR_CTRL_TEMP_EN_MSK                    BIT(3)
 
+#define BMI270_STEP_SC26_WTRMRK_MSK                    GENMASK(9, 0)
 #define BMI270_STEP_SC26_RST_CNT_MSK                   BIT(10)
 #define BMI270_STEP_SC26_EN_CNT_MSK                    BIT(12)
 
@@ -101,6 +110,10 @@
 #define BMI270_TEMP_OFFSET                             11776
 #define BMI270_TEMP_SCALE                              1953125
 
+/* See page 90 of datasheet. The step counter "holds implicitly a 20x factor" */
+#define BMI270_STEP_COUNTER_FACTOR                     20
+#define BMI270_STEP_COUNTER_MAX                                20460
+
 #define BMI260_INIT_DATA_FILE "bmi260-init-data.fw"
 #define BMI270_INIT_DATA_FILE "bmi270-init-data.fw"
 
@@ -396,6 +409,36 @@ static int bmi270_read_steps(struct bmi270_data *data, int *val)
        return IIO_VAL_INT;
 }
 
+static int bmi270_int_map_reg(enum bmi270_irq_pin pin)
+{
+       switch (pin) {
+       case BMI270_IRQ_INT1:
+               return BMI270_INT1_MAP_FEAT_REG;
+       case BMI270_IRQ_INT2:
+               return BMI270_INT2_MAP_FEAT_REG;
+       default:
+               return -EINVAL;
+       }
+}
+
+static int bmi270_step_wtrmrk_en(struct bmi270_data *data, bool state)
+{
+       int reg;
+
+       guard(mutex)(&data->mutex);
+       if (!data->steps_enabled)
+               return -EINVAL;
+
+       reg = bmi270_int_map_reg(data->irq_pin);
+       if (reg < 0)
+               return reg;
+
+       return regmap_update_bits(data->regmap, reg,
+                                 BMI270_INT_MAP_FEAT_STEP_CNT_WTRMRK_MSK,
+                                 FIELD_PREP(BMI270_INT_MAP_FEAT_STEP_CNT_WTRMRK_MSK,
+                                            state));
+}
+
 static int bmi270_set_scale(struct bmi270_data *data, int chan_type, int uscale)
 {
        int i;
@@ -552,19 +595,31 @@ static irqreturn_t bmi270_irq_thread_handler(int irq, void *private)
 {
        struct iio_dev *indio_dev = private;
        struct bmi270_data *data = iio_priv(indio_dev);
-       unsigned int status;
+       unsigned int status0, status1;
+       s64 timestamp = iio_get_time_ns(indio_dev);
        int ret;
 
        scoped_guard(mutex, &data->mutex) {
+               ret = regmap_read(data->regmap, BMI270_INT_STATUS_0_REG,
+                                 &status0);
+               if (ret)
+                       return IRQ_NONE;
+
                ret = regmap_read(data->regmap, BMI270_INT_STATUS_1_REG,
-                                 &status);
+                                 &status1);
                if (ret)
                        return IRQ_NONE;
        }
 
-       if (FIELD_GET(BMI270_INT_STATUS_1_ACC_GYR_DRDY_MSK, status))
+       if (FIELD_GET(BMI270_INT_STATUS_1_ACC_GYR_DRDY_MSK, status1))
                iio_trigger_poll_nested(data->trig);
 
+       if (FIELD_GET(BMI270_INT_STATUS_0_STEP_CNT_MSK, status0))
+               iio_push_event(indio_dev, IIO_UNMOD_EVENT_CODE(IIO_STEPS, 0,
+                                                              IIO_EV_TYPE_CHANGE,
+                                                              IIO_EV_DIR_NONE),
+                              timestamp);
+
        return IRQ_HANDLED;
 }
 
@@ -772,10 +827,116 @@ static int bmi270_read_avail(struct iio_dev *indio_dev,
        }
 }
 
+static int bmi270_write_event_config(struct iio_dev *indio_dev,
+                                    const struct iio_chan_spec *chan,
+                                    enum iio_event_type type,
+                                    enum iio_event_direction dir, bool state)
+{
+       struct bmi270_data *data = iio_priv(indio_dev);
+
+       switch (type) {
+       case IIO_EV_TYPE_CHANGE:
+               return bmi270_step_wtrmrk_en(data, state);
+       default:
+               return -EINVAL;
+       }
+}
+
+static int bmi270_read_event_config(struct iio_dev *indio_dev,
+                                   const struct iio_chan_spec *chan,
+                                   enum iio_event_type type,
+                                   enum iio_event_direction dir)
+{
+       struct bmi270_data *data = iio_priv(indio_dev);
+       int ret, reg, regval;
+
+       guard(mutex)(&data->mutex);
+
+       switch (chan->type) {
+       case IIO_STEPS:
+               reg = bmi270_int_map_reg(data->irq_pin);
+               if (reg)
+                       return reg;
+
+               ret = regmap_read(data->regmap, reg, &regval);
+               if (ret)
+                       return ret;
+               return FIELD_GET(BMI270_INT_MAP_FEAT_STEP_CNT_WTRMRK_MSK,
+                                regval) ? 1 : 0;
+       default:
+               return -EINVAL;
+       }
+}
+
+static int bmi270_write_event_value(struct iio_dev *indio_dev,
+                                   const struct iio_chan_spec *chan,
+                                   enum iio_event_type type,
+                                   enum iio_event_direction dir,
+                                   enum iio_event_info info,
+                                   int val, int val2)
+{
+       struct bmi270_data *data = iio_priv(indio_dev);
+       unsigned int raw;
+
+       guard(mutex)(&data->mutex);
+
+       switch (type) {
+       case IIO_EV_TYPE_CHANGE:
+               if (!in_range(val, 0, BMI270_STEP_COUNTER_MAX + 1))
+                       return -EINVAL;
+
+               raw = val / BMI270_STEP_COUNTER_FACTOR;
+               return bmi270_update_feature_reg(data, BMI270_SC_26_REG,
+                                                BMI270_STEP_SC26_WTRMRK_MSK,
+                                                FIELD_PREP(BMI270_STEP_SC26_WTRMRK_MSK,
+                                                           raw));
+       default:
+               return -EINVAL;
+       }
+}
+
+static int bmi270_read_event_value(struct iio_dev *indio_dev,
+                                  const struct iio_chan_spec *chan,
+                                  enum iio_event_type type,
+                                  enum iio_event_direction dir,
+                                  enum iio_event_info info,
+                                  int *val, int *val2)
+{
+       struct bmi270_data *data = iio_priv(indio_dev);
+       unsigned int raw;
+       u16 regval;
+       int ret;
+
+       guard(mutex)(&data->mutex);
+
+       switch (type) {
+       case IIO_EV_TYPE_CHANGE:
+               ret = bmi270_read_feature_reg(data, BMI270_SC_26_REG, &regval);
+               if (ret)
+                       return ret;
+
+               raw = FIELD_GET(BMI270_STEP_SC26_WTRMRK_MSK, regval);
+               *val = raw * BMI270_STEP_COUNTER_FACTOR;
+               return IIO_VAL_INT;
+       default:
+               return -EINVAL;
+       }
+}
+
+static const struct iio_event_spec bmi270_step_wtrmrk_event = {
+       .type = IIO_EV_TYPE_CHANGE,
+       .dir = IIO_EV_DIR_NONE,
+       .mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE) | BIT(IIO_EV_INFO_VALUE),
+};
+
 static const struct iio_info bmi270_info = {
        .read_raw = bmi270_read_raw,
        .write_raw = bmi270_write_raw,
        .read_avail = bmi270_read_avail,
+       .write_event_config = bmi270_write_event_config,
+       .read_event_config = bmi270_read_event_config,
+       .write_event_value = bmi270_write_event_value,
+       .read_event_value = bmi270_read_event_value,
 };
 
 #define BMI270_ACCEL_CHANNEL(_axis) {                          \
@@ -835,6 +996,8 @@ static const struct iio_chan_spec bmi270_channels[] = {
                .info_mask_separate = BIT(IIO_CHAN_INFO_ENABLE) |
                                      BIT(IIO_CHAN_INFO_PROCESSED),
                .scan_index = -1, /* No buffer support */
+               .event_spec = &bmi270_step_wtrmrk_event,
+               .num_event_specs = 1,
        },
        IIO_CHAN_SOFT_TIMESTAMP(BMI270_SCAN_TIMESTAMP),
 };