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

Denis Benato
2024-08-11T16:12:12Z

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

Signed-off-by: Denis Benato <benato.denis96@gmail.com>
---
drivers/iio/imu/bmi323/bmi323.h | 1 +
drivers/iio/imu/bmi323/bmi323_core.c | 183 ++++++++++++++++++++++++++-
drivers/iio/imu/bmi323/bmi323_i2c.c | 8 ++
drivers/iio/imu/bmi323/bmi323_spi.c | 8 ++
4 files changed, 194 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/imu/bmi323/bmi323.h b/drivers/iio/imu/bmi323/bmi323.h
index 209bccb1f335..9fd3c5db7520 100644
--- a/drivers/iio/imu/bmi323/bmi323.h
+++ b/drivers/iio/imu/bmi323/bmi323.h
@@ -204,6 +204,7 @@

struct device;
int bmi323_core_probe(struct device *dev);
+void bmi323_core_remove(struct device *dev);
extern const struct regmap_config bmi323_regmap_config;
extern const struct dev_pm_ops bmi323_core_pm_ops;

diff --git a/drivers/iio/imu/bmi323/bmi323_core.c b/drivers/iio/imu/bmi323/bmi323_core.c
index 4b2b211a3e88..edb9ce4e66a0 100644
--- a/drivers/iio/imu/bmi323/bmi323_core.c
+++ b/drivers/iio/imu/bmi323/bmi323_core.c
@@ -118,6 +118,24 @@ static const struct bmi323_hw bmi323_hw[2] = {
},
};

+struct bmi323_ext_regs_settings {
+ unsigned int reg;
+ unsigned int val;
+};
+
+struct bmi323_regs_settings {
+ unsigned int reg;
+ unsigned int val;
+};
+
+#define EXT_SETTING_REGISTERS 12
+#define SETTING_REGISTERS 9
+
+struct bmi323_regs_runtime_pm {
+ struct bmi323_regs_settings reg_settings[SETTING_REGISTERS];
+ struct bmi323_ext_regs_settings ext_settings[EXT_SETTING_REGISTERS];
+};
+
struct bmi323_data {
struct device *dev;
struct regmap *regmap;
@@ -130,6 +148,7 @@ 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
@@ -1982,7 +2001,7 @@ static int bmi323_set_bw(struct bmi323_data *data,
FIELD_PREP(BMI323_ACC_GYRO_CONF_BW_MSK, bw));
}

-static int bmi323_init(struct bmi323_data *data)
+static int bmi323_init(struct bmi323_data *data, bool first_init)
{
int ret, val;

@@ -2030,6 +2049,9 @@ static int bmi323_init(struct bmi323_data *data)
return dev_err_probe(data->dev, -EINVAL,
"Sensor power error = 0x%x\n", val);

+ if (!first_init)
+ return 0;
+
/*
* Set the Bandwidth coefficient which defines the 3 dB cutoff
* frequency in relation to the ODR.
@@ -2078,9 +2100,32 @@ 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;
+ data->runtime_pm_status.reg_settings[0].reg = BMI323_INT_MAP1_REG;
+ data->runtime_pm_status.reg_settings[1].reg = BMI323_INT_MAP2_REG;
+ data->runtime_pm_status.reg_settings[2].reg = BMI323_IO_INT_CTR_REG;
+ data->runtime_pm_status.reg_settings[3].reg = BMI323_IO_INT_CONF_REG;
+ data->runtime_pm_status.reg_settings[4].reg = BMI323_ACC_CONF_REG;
+ data->runtime_pm_status.reg_settings[5].reg = BMI323_GYRO_CONF_REG;
+ data->runtime_pm_status.reg_settings[6].reg = BMI323_FEAT_IO0_REG;
+ data->runtime_pm_status.reg_settings[7].reg = BMI323_FIFO_WTRMRK_REG;
+ data->runtime_pm_status.reg_settings[8].reg = BMI323_FIFO_CONF_REG;
+ data->runtime_pm_status.ext_settings[0].reg = BMI323_GEN_SET1_REG;
+ data->runtime_pm_status.ext_settings[1].reg = BMI323_TAP1_REG;
+ data->runtime_pm_status.ext_settings[2].reg = BMI323_TAP2_REG;
+ data->runtime_pm_status.ext_settings[3].reg = BMI323_TAP3_REG;
+ data->runtime_pm_status.ext_settings[4].reg = BMI323_FEAT_IO0_S_TAP_MSK;
+ data->runtime_pm_status.ext_settings[5].reg = BMI323_STEP_SC1_REG;
+ data->runtime_pm_status.ext_settings[6].reg = BMI323_ANYMO1_REG;
+ data->runtime_pm_status.ext_settings[7].reg = BMI323_NOMO1_REG;
+ data->runtime_pm_status.ext_settings[8].reg = BMI323_ANYMO1_REG + BMI323_MO2_OFFSET;
+ data->runtime_pm_status.ext_settings[9].reg = BMI323_NOMO1_REG + BMI323_MO2_OFFSET;
+ data->runtime_pm_status.ext_settings[10].reg = BMI323_ANYMO1_REG + BMI323_MO3_OFFSET;
+ data->runtime_pm_status.ext_settings[11].reg = BMI323_NOMO1_REG + BMI323_MO3_OFFSET;
mutex_init(&data->mutex);

- ret = bmi323_init(data);
+ ret = bmi323_init(data, true);
if (ret)
return -EINVAL;

@@ -2117,21 +2162,147 @@ 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);

+void bmi323_core_remove(struct device *dev)
+{
+ struct regmap *const regmap = dev_get_regmap(dev, NULL);
+
+ /*
+ * Place the peripheral in its lowest power consuming state.
+ */
+ if (regmap)
+ regmap_write(regmap, BMI323_CMD_REG, BMI323_RST_VAL);
+}
+EXPORT_SYMBOL_NS_GPL(bmi323_core_remove, IIO_BMI323);
+
#if defined(CONFIG_PM)
static int bmi323_core_runtime_suspend(struct device *dev)
{
- struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct iio_dev *const indio_dev = dev_get_drvdata(dev);
+ struct bmi323_data *const data = iio_priv(indio_dev);
+
+ int ret = 0;
+
+ guard(mutex)(&data->mutex);

- return iio_device_suspend_triggering(indio_dev);
+ 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 < SETTING_REGISTERS; ++i) {
+ ret = regmap_read(data->regmap,
+ data->runtime_pm_status.reg_settings[i].reg,
+ &data->runtime_pm_status.reg_settings[i].val);
+ if (ret) {
+ dev_err(data->dev, "Error reading bmi323 reg 0x%x: %d\n",
+ data->runtime_pm_status.ext_settings[i].reg, ret);
+ return ret;
+ }
+ }
+
+ /*
+ * Save external registers meant to be restored by resume pm callback.
+ */
+ for (unsigned int i = 0; i < EXT_SETTING_REGISTERS; ++i) {
+ ret = bmi323_read_ext_reg(data,
+ data->runtime_pm_status.ext_settings[i].reg,
+ &data->runtime_pm_status.ext_settings[i].val);
+ if (ret) {
+ dev_err(data->dev, "Error reading bmi323 external reg 0x%x: %d\n",
+ data->runtime_pm_status.ext_settings[i].reg, 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 0;
}

static int bmi323_core_runtime_resume(struct device *dev)
{
- struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct iio_dev *const indio_dev = dev_get_drvdata(dev);
+ struct bmi323_data *const data = iio_priv(indio_dev);
+
+ int ret = 0;
+
+ 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, false);
+ 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;
+ }
+
+ /*
+ * Restore external registers saved by suspend pm callback.
+ */
+ for (unsigned int i = 0; i < EXT_SETTING_REGISTERS; ++i) {
+ ret = bmi323_write_ext_reg(data,
+ data->runtime_pm_status.ext_settings[i].reg,
+ data->runtime_pm_status.ext_settings[i].val);
+ if (ret) {
+ dev_err(data->dev, "Error writing bmi323 external reg 0x%x: %d\n",
+ data->runtime_pm_status.ext_settings[i].reg, ret);
+ return ret;
+ }
+ }
+
+ /*
+ * Restore registers saved by suspend pm callback.
+ */
+ for (unsigned int i = 0; i < SETTING_REGISTERS; ++i) {
+ ret = regmap_write(data->regmap,
+ data->runtime_pm_status.reg_settings[i].reg,
+ data->runtime_pm_status.reg_settings[i].val);
+ if (ret) {
+ dev_err(data->dev, "Error writing bmi323 reg 0x%x: %d\n",
+ data->runtime_pm_status.reg_settings[i].reg, ret);
+ return ret;
+ }
+ }
+
+ 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;
+ }
+ }
+
+ unsigned int val;
+
+ 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);
}
diff --git a/drivers/iio/imu/bmi323/bmi323_i2c.c b/drivers/iio/imu/bmi323/bmi323_i2c.c
index 0ba5d69d8329..2d93861281eb 100644
--- a/drivers/iio/imu/bmi323/bmi323_i2c.c
+++ b/drivers/iio/imu/bmi323/bmi323_i2c.c
@@ -93,6 +93,13 @@ static int bmi323_i2c_probe(struct i2c_client *i2c)
return bmi323_core_probe(dev);
}

+static void bmi323_i2c_remove(struct i2c_client *i2c)
+{
+ struct device *const dev = &i2c->dev;
+
+ bmi323_core_remove(dev);
+}
+
static const struct acpi_device_id bmi323_acpi_match[] = {
/*
* The "BOSC0200" identifier used here is not unique to bmi323 devices.
@@ -133,6 +140,7 @@ static struct i2c_driver bmi323_i2c_driver = {
.acpi_match_table = bmi323_acpi_match,
},
.probe = bmi323_i2c_probe,
+ .remove = bmi323_i2c_remove,
.id_table = bmi323_i2c_ids,
};
module_i2c_driver(bmi323_i2c_driver);
diff --git a/drivers/iio/imu/bmi323/bmi323_spi.c b/drivers/iio/imu/bmi323/bmi323_spi.c
index 9de3ade78d71..f42c49c471c1 100644
--- a/drivers/iio/imu/bmi323/bmi323_spi.c
+++ b/drivers/iio/imu/bmi323/bmi323_spi.c
@@ -64,6 +64,13 @@ static int bmi323_spi_probe(struct spi_device *spi)
return bmi323_core_probe(dev);
}

+static void bmi323_spi_remove(struct spi_device *spi)
+{
+ struct device *const dev = &spi->dev;
+
+ bmi323_core_remove(dev);
+}
+
static const struct spi_device_id bmi323_spi_ids[] = {
{ "bmi323" },
{ }
@@ -83,6 +90,7 @@ static struct spi_driver bmi323_spi_driver = {
.of_match_table = bmi323_of_spi_match,
},
.probe = bmi323_spi_probe,
+ .remove = bmi323_spi_remove,
.id_table = bmi323_spi_ids,
};
module_spi_driver(bmi323_spi_driver);
--
2.46.0