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

Jonathan Cameron
2024-08-26T10:23:47Z

On Sat, 24 Aug 2024 16:11:22 +0200
Denis Benato <benato.denis96@gmail.com> wrote:

> 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>
Applied with some whitespace tweaks.

> ---
> 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);
> }