[PATCH v3 1/1] iio: bmi323: peripheral in lowest power state on suspend

Denis Benato
2024-08-24T14:11:38Z

The bmi323 is mounted on some devices that are powered
by an internal battery: help in reducing system overall power drain
while the system is in s2idle or the imu driver is not loaded
by resetting it in its lowest power draining state.

Signed-off-by: Denis Benato <benato.denis96@gmail.com>
---
drivers/iio/imu/bmi323/bmi323_core.c | 155 ++++++++++++++++++++++++++-
1 file changed, 153 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/imu/bmi323/bmi323_core.c b/drivers/iio/imu/bmi323/bmi323_core.c
index 4b2b211a3e88..57be22c97cb9 100644
--- a/drivers/iio/imu/bmi323/bmi323_core.c
+++ b/drivers/iio/imu/bmi323/bmi323_core.c
@@ -118,6 +118,38 @@ static const struct bmi323_hw bmi323_hw[2] = {
},
};

+static const unsigned int bmi323_reg_savestate[] = {
+ BMI323_INT_MAP1_REG,
+ BMI323_INT_MAP2_REG,
+ BMI323_IO_INT_CTR_REG,
+ BMI323_IO_INT_CONF_REG,
+ BMI323_ACC_CONF_REG,
+ BMI323_GYRO_CONF_REG,
+ BMI323_FEAT_IO0_REG,
+ BMI323_FIFO_WTRMRK_REG,
+ BMI323_FIFO_CONF_REG
+};
+
+static const unsigned int bmi323_ext_reg_savestate[] = {
+ BMI323_GEN_SET1_REG,
+ BMI323_TAP1_REG,
+ BMI323_TAP2_REG,
+ BMI323_TAP3_REG,
+ BMI323_FEAT_IO0_S_TAP_MSK,
+ BMI323_STEP_SC1_REG,
+ BMI323_ANYMO1_REG,
+ BMI323_NOMO1_REG,
+ BMI323_ANYMO1_REG + BMI323_MO2_OFFSET,
+ BMI323_NOMO1_REG + BMI323_MO2_OFFSET,
+ BMI323_ANYMO1_REG + BMI323_MO3_OFFSET,
+ BMI323_NOMO1_REG + BMI323_MO3_OFFSET
+};
+
+struct bmi323_regs_runtime_pm {
+ unsigned int reg_settings[ARRAY_SIZE(bmi323_reg_savestate)];
+ unsigned int ext_reg_settings[ARRAY_SIZE(bmi323_ext_reg_savestate)];
+};
+
struct bmi323_data {
struct device *dev;
struct regmap *regmap;
@@ -130,6 +162,7 @@ struct bmi323_data {
u32 odrns[BMI323_SENSORS_CNT];
u32 odrhz[BMI323_SENSORS_CNT];
unsigned int feature_events;
+ struct bmi323_regs_runtime_pm runtime_pm_status;

/*
* Lock to protect the members of device's private data from concurrent
@@ -1972,6 +2005,11 @@ static void bmi323_disable(void *data_ptr)

bmi323_set_mode(data, BMI323_ACCEL, ACC_GYRO_MODE_DISABLE);
bmi323_set_mode(data, BMI323_GYRO, ACC_GYRO_MODE_DISABLE);
+
+ /*
+ * Place the peripheral in its lowest power consuming state.
+ */
+ regmap_write(data->regmap, BMI323_CMD_REG, BMI323_RST_VAL);
}

static int bmi323_set_bw(struct bmi323_data *data,
@@ -2030,6 +2068,13 @@ static int bmi323_init(struct bmi323_data *data)
return dev_err_probe(data->dev, -EINVAL,
"Sensor power error = 0x%x\n", val);

+ return 0;
+}
+
+static int bmi323_init_reset(struct bmi323_data *data)
+{
+ int ret;
+
/*
* Set the Bandwidth coefficient which defines the 3 dB cutoff
* frequency in relation to the ODR.
@@ -2078,12 +2123,18 @@ int bmi323_core_probe(struct device *dev)
data = iio_priv(indio_dev);
data->dev = dev;
data->regmap = regmap;
+ data->irq_pin = BMI323_IRQ_DISABLED;
+ data->state = BMI323_IDLE;
mutex_init(&data->mutex);

ret = bmi323_init(data);
if (ret)
return -EINVAL;

+ ret = bmi323_init_reset(data);
+ if (ret)
+ return -EINVAL;
+
if (!iio_read_acpi_mount_matrix(dev, &data->orientation, "ROTM")) {
ret = iio_read_mount_matrix(dev, &data->orientation);
if (ret)
@@ -2117,7 +2168,7 @@ int bmi323_core_probe(struct device *dev)
return dev_err_probe(data->dev, ret,
"Unable to register iio device\n");

- return 0;
+ return bmi323_fifo_disable(data);
}
EXPORT_SYMBOL_NS_GPL(bmi323_core_probe, IIO_BMI323);

@@ -2125,13 +2176,113 @@ EXPORT_SYMBOL_NS_GPL(bmi323_core_probe, IIO_BMI323);
static int bmi323_core_runtime_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct bmi323_data *data = iio_priv(indio_dev);
+ struct bmi323_regs_runtime_pm *savestate = &data->runtime_pm_status;
+ int ret;
+
+ guard(mutex)(&data->mutex);
+
+ ret = iio_device_suspend_triggering(indio_dev);
+ if (ret)
+ return ret;
+
+ /* Save registers meant to be restored by resume pm callback. */
+ for (unsigned int i = 0; i < ARRAY_SIZE(bmi323_reg_savestate); i++) {
+ ret = regmap_read(data->regmap, bmi323_reg_savestate[i],
+ &savestate->reg_settings[i]);
+ if (ret) {
+ dev_err(data->dev, "Error reading bmi323 reg 0x%x: %d\n",
+ bmi323_reg_savestate[i], ret);
+ return ret;
+ }
+ }
+
+ for (unsigned int i = 0; i < ARRAY_SIZE(bmi323_ext_reg_savestate); i++) {
+ ret = bmi323_read_ext_reg(data, bmi323_reg_savestate[i],
+ &savestate->reg_settings[i]);
+ if (ret) {
+ dev_err(data->dev, "Error reading bmi323 external reg 0x%x: %d\n",
+ bmi323_reg_savestate[i], ret);
+ return ret;
+ }
+ }
+
+ /* Perform soft reset to place the device in its lowest power state. */
+ ret = regmap_write(data->regmap, BMI323_CMD_REG, BMI323_RST_VAL);
+ if (ret)
+ return ret;

- return iio_device_suspend_triggering(indio_dev);
+ return 0;
}

static int bmi323_core_runtime_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct bmi323_data *data = iio_priv(indio_dev);
+ struct bmi323_regs_runtime_pm *savestate = &data->runtime_pm_status;
+ unsigned int val;
+ int ret;
+
+ guard(mutex)(&data->mutex);
+
+ /*
+ * Perform the device power-on and initial setup once again
+ * after being reset in the lower power state by runtime-pm.
+ */
+ ret = bmi323_init(data);
+ if (!ret)
+ return ret;
+
+ /* Register must be cleared before changing an active config */
+ ret = regmap_write(data->regmap, BMI323_FEAT_IO0_REG, 0);
+ if (ret) {
+ dev_err(data->dev, "Error stopping feature engine\n");
+ return ret;
+ }
+
+ for (unsigned int i = 0; i < ARRAY_SIZE(bmi323_ext_reg_savestate); i++) {
+ ret = bmi323_write_ext_reg(data, bmi323_reg_savestate[i],
+ savestate->reg_settings[i]);
+ if (ret) {
+ dev_err(data->dev, "Error writing bmi323 external reg 0x%x: %d\n",
+ bmi323_reg_savestate[i], ret);
+ return ret;
+ }
+ }
+
+ for (unsigned int i = 0; i < ARRAY_SIZE(bmi323_reg_savestate); i++) {
+ ret = regmap_write(data->regmap, bmi323_reg_savestate[i],
+ savestate->reg_settings[i]);
+ if (ret) {
+ dev_err(data->dev, "Error writing bmi323 reg 0x%x: %d\n",
+ bmi323_reg_savestate[i], ret);
+ return ret;
+ }
+ }
+
+ /*
+ * Clear old FIFO samples that might be generated before suspend
+ * or generated from a peripheral state not equal to the saved one.
+ */
+ if (data->state == BMI323_BUFFER_FIFO) {
+ ret = regmap_write(data->regmap, BMI323_FIFO_CTRL_REG,
+ BMI323_FIFO_FLUSH_MSK);
+ if (ret) {
+ dev_err(data->dev, "Error flushing FIFO buffer: %d\n", ret);
+ return ret;
+ }
+ }
+
+ ret = regmap_read(data->regmap, BMI323_ERR_REG, &val);
+ if (ret) {
+ dev_err(data->dev, "Error reading bmi323 error register: %d\n", ret);
+ return ret;
+ }
+
+ if (val) {
+ dev_err(data->dev, "Sensor power error in PM = 0x%x\n", val);
+ return -EINVAL;
+ }

return iio_device_resume_triggering(indio_dev);
}
--
2.46.0