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iio: bmi323: peripheral in lowest power state on suspend
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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>
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@NeroReflex @BoukeHaarsma23
NeroReflex authored and BoukeHaarsma23 committed Aug 29, 2024
1 parent b79275b commit 2c3c6f7
Showing 1 changed file with 223 additions and 2 deletions.
225 changes: 223 additions & 2 deletions drivers/iio/imu/bmi323/bmi323_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -118,6 +118,84 @@ static const struct bmi323_hw bmi323_hw[2] = {
},
};

struct bmi323_reg_runtime_pm {
unsigned int reg;
};

static const struct bmi323_reg_runtime_pm bmi323_reg_savestate[] = {
{
.reg = BMI323_INT_MAP1_REG
},
{
.reg = BMI323_INT_MAP2_REG
},
{
.reg = BMI323_IO_INT_CTR_REG
},
{
.reg = BMI323_IO_INT_CONF_REG
},
{
.reg = BMI323_ACC_CONF_REG
},
{
.reg = BMI323_GYRO_CONF_REG
},
{
.reg = BMI323_FEAT_IO0_REG
},
{
.reg = BMI323_FIFO_WTRMRK_REG
},
{
.reg = BMI323_FIFO_CONF_REG
}
};

static const struct bmi323_reg_runtime_pm bmi323_ext_reg_savestate[] = {
{
.reg = BMI323_GEN_SET1_REG
},
{
.reg = BMI323_TAP1_REG
},
{
.reg = BMI323_TAP2_REG
},
{
.reg = BMI323_TAP3_REG
},
{
.reg = BMI323_FEAT_IO0_S_TAP_MSK
},
{
.reg = BMI323_STEP_SC1_REG
},
{
.reg = BMI323_ANYMO1_REG
},
{
.reg = BMI323_NOMO1_REG
},
{
.reg = BMI323_ANYMO1_REG + BMI323_MO2_OFFSET
},
{
.reg = BMI323_NOMO1_REG + BMI323_MO2_OFFSET
},
{
.reg = BMI323_ANYMO1_REG + BMI323_MO3_OFFSET
},
{
.reg = 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;
Expand All @@ -130,6 +208,7 @@ 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
Expand Down Expand Up @@ -1972,6 +2051,11 @@ 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,
Expand Down Expand Up @@ -2030,6 +2114,13 @@ 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.
Expand Down Expand Up @@ -2078,12 +2169,18 @@ 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)
Expand Down Expand Up @@ -2117,21 +2214,145 @@ 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);

#if defined(CONFIG_PM)
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;

return iio_device_suspend_triggering(indio_dev);
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++) {
const unsigned int reg_addr = bmi323_reg_savestate[i].reg;
unsigned int *reg_val = &savestate->reg_settings[i];

ret = regmap_read(data->regmap, reg_addr, reg_val);
if (ret) {
dev_err(data->dev, "Error reading bmi323 reg 0x%x: %d\n",
reg_addr, ret);
return ret;
}
}

/*
* Save external registers meant to be restored by resume pm callback.
*/
for (unsigned int i = 0; i < ARRAY_SIZE(bmi323_ext_reg_savestate); i++) {
const unsigned int ext_reg_addr = bmi323_reg_savestate[i].reg;
unsigned int *ext_reg_val = &savestate->reg_settings[i];

ret = bmi323_read_ext_reg(data, ext_reg_addr, ext_reg_val);
if (ret) {
dev_err(data->dev, "Error reading bmi323 external reg 0x%x: %d\n",
ext_reg_addr, 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 bmi323_data *data = iio_priv(indio_dev);
struct bmi323_regs_runtime_pm *savestate = &data->runtime_pm_status;

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;
}

/*
* Restore external registers saved by suspend pm callback.
*/
for (unsigned int i = 0; i < ARRAY_SIZE(bmi323_ext_reg_savestate); i++) {
const unsigned int ext_reg_addr = bmi323_reg_savestate[i].reg;
const unsigned int ext_reg_val = savestate->reg_settings[i];

ret = bmi323_write_ext_reg(data, ext_reg_addr, ext_reg_val);
if (ret) {
dev_err(data->dev, "Error writing bmi323 external reg 0x%x: %d\n",
ext_reg_addr, ret);
return ret;
}
}

/*
* Restore registers saved by suspend pm callback.
*/
for (unsigned int i = 0; i < ARRAY_SIZE(bmi323_reg_savestate); i++) {
const unsigned int reg_addr = bmi323_reg_savestate[i].reg;
const unsigned int reg_val = savestate->reg_settings[i];

ret = regmap_write(data->regmap, reg_addr, reg_val);
if (ret) {
dev_err(data->dev, "Error writing bmi323 reg 0x%x: %d\n",
reg_addr, 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;
}
}

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);
}
Expand Down

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