[PATCH v5 0/3] iio: temperature: mlx90632: Add powermanagement

[PATCH v5 0/3] iio: temperature: mlx90632: Add powermanagement

[cmo]

From: Crt Mori <cmo@melexis.com>

As discussed previously on the group under the
"Controlling device power management from terminal" thread the mlx90632
sensor provides measurement capabilities under sleep_step mode. This
series runtime suspends the unused chip to sleep step mode to save power
but in case of continuous sequential reading it switches to continuous
mode for faster readouts. This value is hardcoded to
MLX90632_MEAS_MAX_TIME (with some buffer) and not user configurable.

The sensor runtime suspension is set to MLX90632_SLEEP_DELAY_MS which is
hardcoded to 3 times as much as MEAS_MAX_TIME.

Changes in v5 (per review comments from Jonathan Cameron):

 - Migrate to devm also for driver removal, along with putting it to low
   power mode

Changes in v4 (per review comments from Jonathan Cameron):

 - Migrate back to devm_pm_runtime_enable and remove the pm_disable function
 - Remove pm stuff from remove and also sleep, since when iio device is
   not registered also sleep makes no sense.
 - Replace use EOPNOTSUPP as per checkpatch suggestion although some drivers
   still use ENOTSUPP.
 - Change the style of read frequency

Changes in v3 (per review comments from Jonathan Cameron):

 - Change the "available" attribute presentation to more recent way
   suggested
 - Replace devm_pm_runtime_enable with enable and devm_add_action_or_reset
 - When suspending device also put it to lower power mode in case there is
   dummy regulator
 - Use more switch cases instead of if/else

Changes in v2:

 - apply review comments from Andy Shevchenko

Crt Mori (3):
  iio: temperature: mlx90632 Add runtime powermanagement modes
  iio: temperature: mlx90632 Read sampling frequency
  iio: temperature: mlx90632 Change return value of sensor measurement
    channel

 drivers/iio/temperature/mlx90632.c | 432 ++++++++++++++++++++++++-----
 1 file changed, 360 insertions(+), 72 deletions(-)

-- 
2.34.1

[PATCH v5 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

[cmo]

From: Crt Mori <cmo@melexis.com>

The sensor can operate in lower power modes and even make measurements when
in those lower powered modes. The decision was taken that if measurement
is not requested within 2 seconds the sensor will remain in SLEEP_STEP
power mode, where measurements are triggered on request with setting the
start of measurement bit (SOB). In this mode the measurements are taking
a bit longer because we need to start it and complete it. Currently, in
continuous mode we read ready data and this mode is activated if sensor
measurement is requested within 2 seconds. The suspend timeout is
increased to 6 seconds (instead of 3 before), because that enables more
measurements in lower power mode (SLEEP_STEP), with the lowest refresh
rate (2 seconds).

Signed-off-by: Crt Mori <cmo@melexis.com>
---
 drivers/iio/temperature/mlx90632.c | 371 +++++++++++++++++++++++------
 1 file changed, 300 insertions(+), 71 deletions(-)

diff --git a/drivers/iio/temperature/mlx90632.c b/drivers/iio/temperature/mlx90632.c
index 549c0ab5c2be..68093639d0e9 100644
--- a/drivers/iio/temperature/mlx90632.c
+++ b/drivers/iio/temperature/mlx90632.c
@@ -6,11 +6,14 @@
  *
  * Driver for the Melexis MLX90632 I2C 16-bit IR thermopile sensor
  */
+#include <linux/bitfield.h>
 #include <linux/delay.h>
+#include <linux/device.h>
 #include <linux/err.h>
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/iopoll.h>
+#include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/limits.h>
 #include <linux/mod_devicetable.h>
@@ -55,6 +58,12 @@
 #define MLX90632_EE_Ha		0x2481 /* Ha customer calib value reg 16bit */
 #define MLX90632_EE_Hb		0x2482 /* Hb customer calib value reg 16bit */
 
+#define MLX90632_EE_MEDICAL_MEAS1      0x24E1 /* Medical measurement 1 16bit */
+#define MLX90632_EE_MEDICAL_MEAS2      0x24E2 /* Medical measurement 2 16bit */
+#define MLX90632_EE_EXTENDED_MEAS1     0x24F1 /* Extended measurement 1 16bit */
+#define MLX90632_EE_EXTENDED_MEAS2     0x24F2 /* Extended measurement 2 16bit */
+#define MLX90632_EE_EXTENDED_MEAS3     0x24F3 /* Extended measurement 3 16bit */
+
 /* Register addresses - volatile */
 #define MLX90632_REG_I2C_ADDR	0x3000 /* Chip I2C address register */
 
@@ -62,13 +71,16 @@
 #define MLX90632_REG_CONTROL	0x3001 /* Control Register address */
 #define   MLX90632_CFG_PWR_MASK		GENMASK(2, 1) /* PowerMode Mask */
 #define   MLX90632_CFG_MTYP_MASK		GENMASK(8, 4) /* Meas select Mask */
+#define   MLX90632_CFG_SOB_MASK BIT(11)
 
 /* PowerModes statuses */
 #define MLX90632_PWR_STATUS(ctrl_val) (ctrl_val << 1)
 #define MLX90632_PWR_STATUS_HALT MLX90632_PWR_STATUS(0) /* hold */
-#define MLX90632_PWR_STATUS_SLEEP_STEP MLX90632_PWR_STATUS(1) /* sleep step*/
+#define MLX90632_PWR_STATUS_SLEEP_STEP MLX90632_PWR_STATUS(1) /* sleep step */
 #define MLX90632_PWR_STATUS_STEP MLX90632_PWR_STATUS(2) /* step */
-#define MLX90632_PWR_STATUS_CONTINUOUS MLX90632_PWR_STATUS(3) /* continuous*/
+#define MLX90632_PWR_STATUS_CONTINUOUS MLX90632_PWR_STATUS(3) /* continuous */
+
+#define MLX90632_EE_RR GENMASK(10, 8) /* Only Refresh Rate bits */
 
 /* Measurement types */
 #define MLX90632_MTYP_MEDICAL 0
@@ -116,8 +128,9 @@
 #define MLX90632_REF_12 	12LL /* ResCtrlRef value of Ch 1 or Ch 2 */
 #define MLX90632_REF_3		12LL /* ResCtrlRef value of Channel 3 */
 #define MLX90632_MAX_MEAS_NUM	31 /* Maximum measurements in list */
-#define MLX90632_SLEEP_DELAY_MS 3000 /* Autosleep delay */
+#define MLX90632_SLEEP_DELAY_MS 6000 /* Autosleep delay */
 #define MLX90632_EXTENDED_LIMIT 27000 /* Extended mode raw value limit */
+#define MLX90632_MEAS_MAX_TIME 2000 /* Max measurement time in ms for the lowest refresh rate */
 
 /**
  * struct mlx90632_data - private data for the MLX90632 device
@@ -130,6 +143,9 @@
  * @object_ambient_temperature: Ambient temperature at object (might differ of
  *                              the ambient temperature of sensor.
  * @regulator: Regulator of the device
+ * @powerstatus: Current POWER status of the device
+ * @interaction_ts: Timestamp of the last temperature read that is used
+ *		    for power management in jiffies
  */
 struct mlx90632_data {
 	struct i2c_client *client;
@@ -139,6 +155,8 @@ struct mlx90632_data {
 	u8 mtyp;
 	u32 object_ambient_temperature;
 	struct regulator *regulator;
+	int powerstatus;
+	unsigned long interaction_ts;
 };
 
 static const struct regmap_range mlx90632_volatile_reg_range[] = {
@@ -158,6 +176,8 @@ static const struct regmap_range mlx90632_read_reg_range[] = {
 	regmap_reg_range(MLX90632_EE_VERSION, MLX90632_EE_Ka),
 	regmap_reg_range(MLX90632_EE_CTRL, MLX90632_EE_I2C_ADDR),
 	regmap_reg_range(MLX90632_EE_Ha, MLX90632_EE_Hb),
+	regmap_reg_range(MLX90632_EE_MEDICAL_MEAS1, MLX90632_EE_MEDICAL_MEAS2),
+	regmap_reg_range(MLX90632_EE_EXTENDED_MEAS1, MLX90632_EE_EXTENDED_MEAS3),
 	regmap_reg_range(MLX90632_REG_I2C_ADDR, MLX90632_REG_CONTROL),
 	regmap_reg_range(MLX90632_REG_I2C_CMD, MLX90632_REG_I2C_CMD),
 	regmap_reg_range(MLX90632_REG_STATUS, MLX90632_REG_STATUS),
@@ -198,16 +218,38 @@ static const struct regmap_config mlx90632_regmap = {
 
 static s32 mlx90632_pwr_set_sleep_step(struct regmap *regmap)
 {
-	return regmap_update_bits(regmap, MLX90632_REG_CONTROL,
-				  MLX90632_CFG_PWR_MASK,
-				  MLX90632_PWR_STATUS_SLEEP_STEP);
+	struct mlx90632_data *data =
+		iio_priv(dev_get_drvdata(regmap_get_device(regmap)));
+	s32 ret;
+
+	if (data->powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP)
+		return 0;
+
+	ret = regmap_write_bits(regmap, MLX90632_REG_CONTROL, MLX90632_CFG_PWR_MASK,
+				MLX90632_PWR_STATUS_SLEEP_STEP);
+	if (ret < 0)
+		return ret;
+
+	data->powerstatus = MLX90632_PWR_STATUS_SLEEP_STEP;
+	return ret;
 }
 
 static s32 mlx90632_pwr_continuous(struct regmap *regmap)
 {
-	return regmap_update_bits(regmap, MLX90632_REG_CONTROL,
-				  MLX90632_CFG_PWR_MASK,
-				  MLX90632_PWR_STATUS_CONTINUOUS);
+	struct mlx90632_data *data =
+		iio_priv(dev_get_drvdata(regmap_get_device(regmap)));
+	s32 ret;
+
+	if (data->powerstatus == MLX90632_PWR_STATUS_CONTINUOUS)
+		return 0;
+
+	ret = regmap_write_bits(regmap, MLX90632_REG_CONTROL, MLX90632_CFG_PWR_MASK,
+				MLX90632_PWR_STATUS_CONTINUOUS);
+	if (ret < 0)
+		return ret;
+
+	data->powerstatus = MLX90632_PWR_STATUS_CONTINUOUS;
+	return ret;
 }
 
 /**
@@ -219,6 +261,63 @@ static void mlx90632_reset_delay(void)
 	usleep_range(150, 200);
 }
 
+static int mlx90632_get_measurement_time(struct regmap *regmap, u16 meas)
+{
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(regmap, meas, &reg);
+	if (ret < 0)
+		return ret;
+
+	return MLX90632_MEAS_MAX_TIME >> FIELD_GET(MLX90632_EE_RR, reg);
+}
+
+static int mlx90632_calculate_dataset_ready_time(struct mlx90632_data *data)
+{
+	unsigned int refresh_time;
+	int ret;
+
+	if (data->mtyp == MLX90632_MTYP_MEDICAL) {
+		ret = mlx90632_get_measurement_time(data->regmap,
+						    MLX90632_EE_MEDICAL_MEAS1);
+		if (ret < 0)
+			return ret;
+
+		refresh_time = ret;
+
+		ret = mlx90632_get_measurement_time(data->regmap,
+						    MLX90632_EE_MEDICAL_MEAS2);
+		if (ret < 0)
+			return ret;
+
+		refresh_time += ret;
+	} else {
+		ret = mlx90632_get_measurement_time(data->regmap,
+						    MLX90632_EE_EXTENDED_MEAS1);
+		if (ret < 0)
+			return ret;
+
+		refresh_time = ret;
+
+		ret = mlx90632_get_measurement_time(data->regmap,
+						    MLX90632_EE_EXTENDED_MEAS2);
+		if (ret < 0)
+			return ret;
+
+		refresh_time += ret;
+
+		ret = mlx90632_get_measurement_time(data->regmap,
+						    MLX90632_EE_EXTENDED_MEAS3);
+		if (ret < 0)
+			return ret;
+
+		refresh_time += ret;
+	}
+
+	return refresh_time;
+}
+
 /**
  * mlx90632_perform_measurement() - Trigger and retrieve current measurement cycle
  * @data: pointer to mlx90632_data object containing regmap information
@@ -249,26 +348,75 @@ static int mlx90632_perform_measurement(struct mlx90632_data *data)
 	return (reg_status & MLX90632_STAT_CYCLE_POS) >> 2;
 }
 
-static int mlx90632_set_meas_type(struct regmap *regmap, u8 type)
+/**
+ * mlx90632_perform_measurement_burst() - Trigger and retrieve current measurement
+ * cycle in step sleep mode
+ * @data: pointer to mlx90632_data object containing regmap information
+ *
+ * Perform a measurement and return 2 as measurement cycle position reported
+ * by sensor. This is a blocking function for amount dependent on the sensor
+ * refresh rate.
+ */
+static int mlx90632_perform_measurement_burst(struct mlx90632_data *data)
 {
+	unsigned int reg_status;
 	int ret;
 
-	if ((type != MLX90632_MTYP_MEDICAL) && (type != MLX90632_MTYP_EXTENDED))
-		return -EINVAL;
+	ret = regmap_write_bits(data->regmap, MLX90632_REG_CONTROL,
+				MLX90632_CFG_SOB_MASK, MLX90632_CFG_SOB_MASK);
+	if (ret < 0)
+		return ret;
 
-	ret = regmap_write(regmap, MLX90632_REG_I2C_CMD, MLX90632_RESET_CMD);
+	ret = mlx90632_calculate_dataset_ready_time(data);
+	if (ret < 0)
+		return ret;
+
+	msleep(ret); /* Wait minimum time for dataset to be ready */
+
+	ret = regmap_read_poll_timeout(data->regmap, MLX90632_REG_STATUS,
+				       reg_status,
+				       (reg_status & MLX90632_STAT_BUSY) == 0,
+				       10000, 100 * 10000);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "data not ready");
+		return -ETIMEDOUT;
+	}
+
+	return 2;
+}
+
+static int mlx90632_set_meas_type(struct mlx90632_data *data, u8 type)
+{
+	int current_powerstatus;
+	int ret;
+
+	if (data->mtyp == type)
+		return 0;
+
+	current_powerstatus = data->powerstatus;
+	ret = mlx90632_pwr_continuous(data->regmap);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(data->regmap, MLX90632_REG_I2C_CMD, MLX90632_RESET_CMD);
 	if (ret < 0)
 		return ret;
 
 	mlx90632_reset_delay();
 
-	ret = regmap_write_bits(regmap, MLX90632_REG_CONTROL,
+	ret = regmap_update_bits(data->regmap, MLX90632_REG_CONTROL,
 				 (MLX90632_CFG_MTYP_MASK | MLX90632_CFG_PWR_MASK),
 				 (MLX90632_MTYP_STATUS(type) | MLX90632_PWR_STATUS_HALT));
 	if (ret < 0)
 		return ret;
 
-	return mlx90632_pwr_continuous(regmap);
+	data->mtyp = type;
+	data->powerstatus = MLX90632_PWR_STATUS_HALT;
+
+	if (current_powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP)
+		return mlx90632_pwr_set_sleep_step(data->regmap);
+
+	return mlx90632_pwr_continuous(data->regmap);
 }
 
 static int mlx90632_channel_new_select(int perform_ret, uint8_t *channel_new,
@@ -355,11 +503,30 @@ static int mlx90632_read_all_channel(struct mlx90632_data *data,
 	s32 ret, measurement;
 
 	mutex_lock(&data->lock);
-	measurement = mlx90632_perform_measurement(data);
-	if (measurement < 0) {
-		ret = measurement;
+	ret = mlx90632_set_meas_type(data, MLX90632_MTYP_MEDICAL);
+	if (ret < 0)
+		goto read_unlock;
+
+	switch (data->powerstatus) {
+	case MLX90632_PWR_STATUS_CONTINUOUS:
+		measurement = mlx90632_perform_measurement(data);
+		if (measurement < 0) {
+			ret = measurement;
+			goto read_unlock;
+		}
+		break;
+	case MLX90632_PWR_STATUS_SLEEP_STEP:
+		measurement = mlx90632_perform_measurement_burst(data);
+		if (measurement < 0) {
+			ret = measurement;
+			goto read_unlock;
+		}
+		break;
+	default:
+		ret = -EOPNOTSUPP;
 		goto read_unlock;
 	}
+
 	ret = mlx90632_read_ambient_raw(data->regmap, ambient_new_raw,
 					ambient_old_raw);
 	if (ret < 0)
@@ -441,14 +608,20 @@ static int mlx90632_read_all_channel_extended(struct mlx90632_data *data, s16 *o
 	s32 ret, meas;
 
 	mutex_lock(&data->lock);
-	ret = mlx90632_set_meas_type(data->regmap, MLX90632_MTYP_EXTENDED);
+	ret = mlx90632_set_meas_type(data, MLX90632_MTYP_EXTENDED);
 	if (ret < 0)
 		goto read_unlock;
 
-	ret = read_poll_timeout(mlx90632_perform_measurement, meas, meas == 19,
-				50000, 800000, false, data);
-	if (ret != 0)
-		goto read_unlock;
+	if (data->powerstatus == MLX90632_PWR_STATUS_CONTINUOUS) {
+		ret = read_poll_timeout(mlx90632_perform_measurement, meas, meas == 19,
+					50000, 800000, false, data);
+		if (ret)
+			goto read_unlock;
+	} else if (data->powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP) {
+		ret = mlx90632_perform_measurement_burst(data);
+		if (ret < 0)
+			goto read_unlock;
+	}
 
 	ret = mlx90632_read_object_raw_extended(data->regmap, object_new_raw);
 	if (ret < 0)
@@ -457,8 +630,6 @@ static int mlx90632_read_all_channel_extended(struct mlx90632_data *data, s16 *o
 	ret = mlx90632_read_ambient_raw_extended(data->regmap, ambient_new_raw, ambient_old_raw);
 
 read_unlock:
-	(void) mlx90632_set_meas_type(data->regmap, MLX90632_MTYP_MEDICAL);
-
 	mutex_unlock(&data->lock);
 	return ret;
 }
@@ -743,12 +914,47 @@ static int mlx90632_calc_ambient_dsp105(struct mlx90632_data *data, int *val)
 	return ret;
 }
 
+/**
+ * mlx90632_pm_interraction_wakeup() - Measure time between user interactions to change powermode
+ * @data: pointer to mlx90632_data object containing interaction_ts information
+ *
+ * Switch to continuous mode when interaction is faster than MLX90632_MEAS_MAX_TIME. Update the
+ * interaction_ts for each function call with the jiffies to enable measurement between function
+ * calls. Initial value of the interaction_ts needs to be set before this function call.
+ */
+static int mlx90632_pm_interraction_wakeup(struct mlx90632_data *data)
+{
+	unsigned long now;
+	int ret;
+
+	now = jiffies;
+	if (time_in_range(now, data->interaction_ts,
+			  data->interaction_ts +
+			  msecs_to_jiffies(MLX90632_MEAS_MAX_TIME + 100))) {
+		if (data->powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP) {
+			ret = mlx90632_pwr_continuous(data->regmap);
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	data->interaction_ts = now;
+
+	return 0;
+}
+
 static int mlx90632_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *channel, int *val,
 			     int *val2, long mask)
 {
 	struct mlx90632_data *data = iio_priv(indio_dev);
 	int ret;
+	int cr;
+
+	pm_runtime_get_sync(&data->client->dev);
+	ret = mlx90632_pm_interraction_wakeup(data);
+	if (ret < 0)
+		goto mlx90632_read_raw_pm;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_PROCESSED:
@@ -756,16 +962,22 @@ static int mlx90632_read_raw(struct iio_dev *indio_dev,
 		case IIO_MOD_TEMP_AMBIENT:
 			ret = mlx90632_calc_ambient_dsp105(data, val);
 			if (ret < 0)
-				return ret;
-			return IIO_VAL_INT;
+				goto mlx90632_read_raw_pm;
+
+			ret = IIO_VAL_INT;
+			break;
 		case IIO_MOD_TEMP_OBJECT:
 			ret = mlx90632_calc_object_dsp105(data, val);
 			if (ret < 0)
-				return ret;
-			return IIO_VAL_INT;
+				goto mlx90632_read_raw_pm;
+
+			ret = IIO_VAL_INT;
+			break;
 		default:
-			return -EINVAL;
+			ret = -EINVAL;
+			break;
 		}
+		break;
 	case IIO_CHAN_INFO_CALIBEMISSIVITY:
 		if (data->emissivity == 1000) {
 			*val = 1;
@@ -774,13 +986,21 @@ static int mlx90632_read_raw(struct iio_dev *indio_dev,
 			*val = 0;
 			*val2 = data->emissivity * 1000;
 		}
-		return IIO_VAL_INT_PLUS_MICRO;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
 	case IIO_CHAN_INFO_CALIBAMBIENT:
 		*val = data->object_ambient_temperature;
-		return IIO_VAL_INT;
+		ret = IIO_VAL_INT;
+		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
+		break;
 	}
+
+mlx90632_read_raw_pm:
+	pm_runtime_mark_last_busy(&data->client->dev);
+	pm_runtime_put_autosuspend(&data->client->dev);
+	return ret;
 }
 
 static int mlx90632_write_raw(struct iio_dev *indio_dev,
@@ -826,12 +1046,14 @@ static const struct iio_info mlx90632_info = {
 	.write_raw = mlx90632_write_raw,
 };
 
-static int mlx90632_sleep(struct mlx90632_data *data)
+static void mlx90632_sleep(void *_data)
 {
+	struct mlx90632_data *data = _data;
+
 	regcache_mark_dirty(data->regmap);
 
 	dev_dbg(&data->client->dev, "Requesting sleep");
-	return mlx90632_pwr_set_sleep_step(data->regmap);
+	mlx90632_pwr_set_sleep_step(data->regmap);
 }
 
 static int mlx90632_wakeup(struct mlx90632_data *data)
@@ -902,6 +1124,7 @@ static int mlx90632_probe(struct i2c_client *client,
 	mlx90632->client = client;
 	mlx90632->regmap = regmap;
 	mlx90632->mtyp = MLX90632_MTYP_MEDICAL;
+	mlx90632->powerstatus = MLX90632_PWR_STATUS_HALT;
 
 	mutex_init(&mlx90632->lock);
 	indio_dev->name = id->name;
@@ -933,6 +1156,13 @@ static int mlx90632_probe(struct i2c_client *client,
 		return ret;
 	}
 
+	ret = devm_add_action_or_reset(&client->dev, mlx90632_sleep, mlx90632);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to setup low power cleanup action %d\n",
+			ret);
+		return ret;
+	}
+
 	ret = regmap_read(mlx90632->regmap, MLX90632_EE_VERSION, &read);
 	if (ret < 0) {
 		dev_err(&client->dev, "read of version failed: %d\n", ret);
@@ -961,34 +1191,17 @@ static int mlx90632_probe(struct i2c_client *client,
 
 	mlx90632->emissivity = 1000;
 	mlx90632->object_ambient_temperature = 25000; /* 25 degrees milliCelsius */
+	mlx90632->interaction_ts = jiffies; /* Set initial value */
 
-	pm_runtime_disable(&client->dev);
-	ret = pm_runtime_set_active(&client->dev);
-	if (ret < 0) {
-		mlx90632_sleep(mlx90632);
-		return ret;
-	}
-	pm_runtime_enable(&client->dev);
+	pm_runtime_get_noresume(&client->dev);
+	pm_runtime_set_active(&client->dev);
+
+	devm_pm_runtime_enable(&client->dev);
 	pm_runtime_set_autosuspend_delay(&client->dev, MLX90632_SLEEP_DELAY_MS);
 	pm_runtime_use_autosuspend(&client->dev);
+	pm_runtime_put_autosuspend(&client->dev);
 
-	return iio_device_register(indio_dev);
-}
-
-static int mlx90632_remove(struct i2c_client *client)
-{
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
-	struct mlx90632_data *data = iio_priv(indio_dev);
-
-	iio_device_unregister(indio_dev);
-
-	pm_runtime_disable(&client->dev);
-	pm_runtime_set_suspended(&client->dev);
-	pm_runtime_put_noidle(&client->dev);
-
-	mlx90632_sleep(data);
-
-	return 0;
+	return devm_iio_device_register(&client->dev, indio_dev);
 }
 
 static const struct i2c_device_id mlx90632_id[] = {
@@ -1003,33 +1216,49 @@ static const struct of_device_id mlx90632_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, mlx90632_of_match);
 
-static int __maybe_unused mlx90632_pm_suspend(struct device *dev)
+static int mlx90632_pm_suspend(struct device *dev)
 {
-	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
-	struct mlx90632_data *data = iio_priv(indio_dev);
+	struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
+	int ret;
+
+	ret = mlx90632_pwr_set_sleep_step(data->regmap);
+	if (ret < 0)
+		return ret;
+
+	ret = regulator_disable(data->regulator);
+	if (ret < 0)
+		dev_err(regmap_get_device(data->regmap),
+			"Failed to disable power regulator: %d\n", ret);
 
-	return mlx90632_sleep(data);
+	return ret;
 }
 
-static int __maybe_unused mlx90632_pm_resume(struct device *dev)
+static int mlx90632_pm_resume(struct device *dev)
 {
-	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
-	struct mlx90632_data *data = iio_priv(indio_dev);
+	struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
+
+	return mlx90632_enable_regulator(data);
+}
+
+static int mlx90632_pm_runtime_suspend(struct device *dev)
+{
+	struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
 
-	return mlx90632_wakeup(data);
+	return mlx90632_pwr_set_sleep_step(data->regmap);
 }
 
-static UNIVERSAL_DEV_PM_OPS(mlx90632_pm_ops, mlx90632_pm_suspend,
-			    mlx90632_pm_resume, NULL);
+const struct dev_pm_ops mlx90632_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(mlx90632_pm_suspend, mlx90632_pm_resume)
+	RUNTIME_PM_OPS(mlx90632_pm_runtime_suspend, NULL, NULL)
+};
 
 static struct i2c_driver mlx90632_driver = {
 	.driver = {
 		.name	= "mlx90632",
 		.of_match_table = mlx90632_of_match,
-		.pm	= &mlx90632_pm_ops,
+		.pm	= pm_ptr(&mlx90632_pm_ops),
 	},
 	.probe = mlx90632_probe,
-	.remove = mlx90632_remove,
 	.id_table = mlx90632_id,
 };
 module_i2c_driver(mlx90632_driver);
-- 
2.34.1

[PATCH v5 2/3] iio: temperature: mlx90632 Read sampling frequency

[cmo]

From: Crt Mori <cmo@melexis.com>

Allow users to read sensor sampling frequency to better plan the
application measurement requests.

Signed-off-by: Crt Mori <cmo@melexis.com>
---
 drivers/iio/temperature/mlx90632.c | 59 ++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/drivers/iio/temperature/mlx90632.c b/drivers/iio/temperature/mlx90632.c
index 68093639d0e9..c0bf385ebd6c 100644
--- a/drivers/iio/temperature/mlx90632.c
+++ b/drivers/iio/temperature/mlx90632.c
@@ -81,6 +81,9 @@
 #define MLX90632_PWR_STATUS_CONTINUOUS MLX90632_PWR_STATUS(3) /* continuous */
 
 #define MLX90632_EE_RR GENMASK(10, 8) /* Only Refresh Rate bits */
+#define MLX90632_REFRESH_RATE(ee_val) FIELD_GET(MLX90632_EE_RR, ee_val)
+					/* Extract Refresh Rate from ee register */
+#define MLX90632_REFRESH_RATE_STATUS(refresh_rate) (refresh_rate << 8)
 
 /* Measurement types */
 #define MLX90632_MTYP_MEDICAL 0
@@ -914,6 +917,32 @@ static int mlx90632_calc_ambient_dsp105(struct mlx90632_data *data, int *val)
 	return ret;
 }
 
+static int mlx90632_get_refresh_rate(struct mlx90632_data *data,
+				     int *refresh_rate)
+{
+	unsigned int meas1;
+	int ret;
+
+	ret = regmap_read(data->regmap, MLX90632_EE_MEDICAL_MEAS1, &meas1);
+	if (ret < 0)
+		return ret;
+
+	*refresh_rate = MLX90632_REFRESH_RATE(meas1);
+
+	return ret;
+}
+
+static const int mlx90632_freqs[][2] = {
+	{0, 500000},
+	{1, 0},
+	{2, 0},
+	{4, 0},
+	{8, 0},
+	{16, 0},
+	{32, 0},
+	{64, 0}
+};
+
 /**
  * mlx90632_pm_interraction_wakeup() - Measure time between user interactions to change powermode
  * @data: pointer to mlx90632_data object containing interaction_ts information
@@ -992,6 +1021,15 @@ static int mlx90632_read_raw(struct iio_dev *indio_dev,
 		*val = data->object_ambient_temperature;
 		ret = IIO_VAL_INT;
 		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = mlx90632_get_refresh_rate(data, &cr);
+		if (ret < 0)
+			goto mlx90632_read_raw_pm;
+
+		*val = mlx90632_freqs[cr][0];
+		*val2 = mlx90632_freqs[cr][1];
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
 	default:
 		ret = -EINVAL;
 		break;
@@ -1025,12 +1063,30 @@ static int mlx90632_write_raw(struct iio_dev *indio_dev,
 	}
 }
 
+static int mlx90632_read_avail(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       const int **vals, int *type, int *length,
+			       long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*vals = (int *)mlx90632_freqs;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		*length = 2 * ARRAY_SIZE(mlx90632_freqs);
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
 static const struct iio_chan_spec mlx90632_channels[] = {
 	{
 		.type = IIO_TEMP,
 		.modified = 1,
 		.channel2 = IIO_MOD_TEMP_AMBIENT,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	},
 	{
 		.type = IIO_TEMP,
@@ -1038,12 +1094,15 @@ static const struct iio_chan_spec mlx90632_channels[] = {
 		.channel2 = IIO_MOD_TEMP_OBJECT,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 			BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) | BIT(IIO_CHAN_INFO_CALIBAMBIENT),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	},
 };
 
 static const struct iio_info mlx90632_info = {
 	.read_raw = mlx90632_read_raw,
 	.write_raw = mlx90632_write_raw,
+	.read_avail = mlx90632_read_avail,
 };
 
 static void mlx90632_sleep(void *_data)
-- 
2.34.1

[PATCH v5 3/3] iio: temperature: mlx90632 Change return value of sensor measurement channel

[cmo]

From: Crt Mori <cmo@melexis.com>

The current EINVAL value is more applicable to embedded library, where
user can actually put the fixed value to the sensor. In case of the
driver if the value of the channel is invalid it is better in inform
userspace that Channel was out of range as that implies more to internal
driver error than invalid input. It also makes for easier debugging of
where the error comes from during the development.

Signed-off-by: Crt Mori <cmo@melexis.com>
---
 drivers/iio/temperature/mlx90632.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/temperature/mlx90632.c b/drivers/iio/temperature/mlx90632.c
index c0bf385ebd6c..daaffe84b617 100644
--- a/drivers/iio/temperature/mlx90632.c
+++ b/drivers/iio/temperature/mlx90632.c
@@ -435,7 +435,7 @@ static int mlx90632_channel_new_select(int perform_ret, uint8_t *channel_new,
 		*channel_old = 1;
 		break;
 	default:
-		return -EINVAL;
+		return -ECHRNG;
 	}
 
 	return 0;
-- 
2.34.1

Re: [PATCH v5 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

[Jonathan Cameron]

On Mon, 19 Sep 2022 10:48:16 +0200
cmo@melexis.com wrote:

> From: Crt Mori <cmo@melexis.com>
> 
> The sensor can operate in lower power modes and even make measurements when
> in those lower powered modes. The decision was taken that if measurement
> is not requested within 2 seconds the sensor will remain in SLEEP_STEP
> power mode, where measurements are triggered on request with setting the
> start of measurement bit (SOB). In this mode the measurements are taking
> a bit longer because we need to start it and complete it. Currently, in
> continuous mode we read ready data and this mode is activated if sensor
> measurement is requested within 2 seconds. The suspend timeout is
> increased to 6 seconds (instead of 3 before), because that enables more
> measurements in lower power mode (SLEEP_STEP), with the lowest refresh
> rate (2 seconds).
Hi Crt,

I'm a little nervous about one change in the flow from earlier versions.
I'm assuming you are sure it is always fine though!

Previously before calling the _sleep() in remove we ensured the device
was powered up. Now that's no longer true. If runtime pm has it in
a low power state it will remain in that state at the point where we call
_sleep(). 

One note/question on original code...  Why bother marking regcache dirty when
we are going down anyway?  It's not wrong as such, just probably not
that useful unless I'm missing something.  Same in the *_wakeup()
that puts the cache back but is only called in probe now.

Which then raises question of why we don't need to deal with the regcache
any more when we turn power off in suspend?

So either we need a statement of why the register state is maintained,
or add the maintenance for that.  Also probably makes sense to drop
the left over maintenance from the probe() and remove() (via devm) paths.

Jonathan

> 
> Signed-off-by: Crt Mori <cmo@melexis.com>
> ---
>  drivers/iio/temperature/mlx90632.c | 371 +++++++++++++++++++++++------
>  1 file changed, 300 insertions(+), 71 deletions(-)
> 
> diff --git a/drivers/iio/temperature/mlx90632.c b/drivers/iio/temperature/mlx90632.c
> index 549c0ab5c2be..68093639d0e9 100644
> --- a/drivers/iio/temperature/mlx90632.c
> +++ b/drivers/iio/temperature/mlx90632.c
> @@ -6,11 +6,14 @@
>   *
>   * Driver for the Melexis MLX90632 I2C 16-bit IR thermopile sensor
>   */
> +#include <linux/bitfield.h>
>  #include <linux/delay.h>
> +#include <linux/device.h>
>  #include <linux/err.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/i2c.h>
>  #include <linux/iopoll.h>
> +#include <linux/jiffies.h>
>  #include <linux/kernel.h>
>  #include <linux/limits.h>
>  #include <linux/mod_devicetable.h>
> @@ -55,6 +58,12 @@
>  #define MLX90632_EE_Ha		0x2481 /* Ha customer calib value reg 16bit */
>  #define MLX90632_EE_Hb		0x2482 /* Hb customer calib value reg 16bit */
>  
> +#define MLX90632_EE_MEDICAL_MEAS1      0x24E1 /* Medical measurement 1 16bit */
> +#define MLX90632_EE_MEDICAL_MEAS2      0x24E2 /* Medical measurement 2 16bit */
> +#define MLX90632_EE_EXTENDED_MEAS1     0x24F1 /* Extended measurement 1 16bit */
> +#define MLX90632_EE_EXTENDED_MEAS2     0x24F2 /* Extended measurement 2 16bit */
> +#define MLX90632_EE_EXTENDED_MEAS3     0x24F3 /* Extended measurement 3 16bit */
> +
>  /* Register addresses - volatile */
>  #define MLX90632_REG_I2C_ADDR	0x3000 /* Chip I2C address register */
>  
> @@ -62,13 +71,16 @@
>  #define MLX90632_REG_CONTROL	0x3001 /* Control Register address */
>  #define   MLX90632_CFG_PWR_MASK		GENMASK(2, 1) /* PowerMode Mask */
>  #define   MLX90632_CFG_MTYP_MASK		GENMASK(8, 4) /* Meas select Mask */
> +#define   MLX90632_CFG_SOB_MASK BIT(11)
>  
>  /* PowerModes statuses */
>  #define MLX90632_PWR_STATUS(ctrl_val) (ctrl_val << 1)
>  #define MLX90632_PWR_STATUS_HALT MLX90632_PWR_STATUS(0) /* hold */
> -#define MLX90632_PWR_STATUS_SLEEP_STEP MLX90632_PWR_STATUS(1) /* sleep step*/
> +#define MLX90632_PWR_STATUS_SLEEP_STEP MLX90632_PWR_STATUS(1) /* sleep step */
>  #define MLX90632_PWR_STATUS_STEP MLX90632_PWR_STATUS(2) /* step */
> -#define MLX90632_PWR_STATUS_CONTINUOUS MLX90632_PWR_STATUS(3) /* continuous*/
> +#define MLX90632_PWR_STATUS_CONTINUOUS MLX90632_PWR_STATUS(3) /* continuous */
> +
> +#define MLX90632_EE_RR GENMASK(10, 8) /* Only Refresh Rate bits */
>  
>  /* Measurement types */
>  #define MLX90632_MTYP_MEDICAL 0
> @@ -116,8 +128,9 @@
>  #define MLX90632_REF_12 	12LL /* ResCtrlRef value of Ch 1 or Ch 2 */
>  #define MLX90632_REF_3		12LL /* ResCtrlRef value of Channel 3 */
>  #define MLX90632_MAX_MEAS_NUM	31 /* Maximum measurements in list */
> -#define MLX90632_SLEEP_DELAY_MS 3000 /* Autosleep delay */
> +#define MLX90632_SLEEP_DELAY_MS 6000 /* Autosleep delay */
>  #define MLX90632_EXTENDED_LIMIT 27000 /* Extended mode raw value limit */
> +#define MLX90632_MEAS_MAX_TIME 2000 /* Max measurement time in ms for the lowest refresh rate */
>  
>  /**
>   * struct mlx90632_data - private data for the MLX90632 device
> @@ -130,6 +143,9 @@
>   * @object_ambient_temperature: Ambient temperature at object (might differ of
>   *                              the ambient temperature of sensor.
>   * @regulator: Regulator of the device
> + * @powerstatus: Current POWER status of the device
> + * @interaction_ts: Timestamp of the last temperature read that is used
> + *		    for power management in jiffies
>   */
>  struct mlx90632_data {
>  	struct i2c_client *client;
> @@ -139,6 +155,8 @@ struct mlx90632_data {
>  	u8 mtyp;
>  	u32 object_ambient_temperature;
>  	struct regulator *regulator;
> +	int powerstatus;
> +	unsigned long interaction_ts;
>  };
>  
>  static const struct regmap_range mlx90632_volatile_reg_range[] = {
> @@ -158,6 +176,8 @@ static const struct regmap_range mlx90632_read_reg_range[] = {
>  	regmap_reg_range(MLX90632_EE_VERSION, MLX90632_EE_Ka),
>  	regmap_reg_range(MLX90632_EE_CTRL, MLX90632_EE_I2C_ADDR),
>  	regmap_reg_range(MLX90632_EE_Ha, MLX90632_EE_Hb),
> +	regmap_reg_range(MLX90632_EE_MEDICAL_MEAS1, MLX90632_EE_MEDICAL_MEAS2),
> +	regmap_reg_range(MLX90632_EE_EXTENDED_MEAS1, MLX90632_EE_EXTENDED_MEAS3),
>  	regmap_reg_range(MLX90632_REG_I2C_ADDR, MLX90632_REG_CONTROL),
>  	regmap_reg_range(MLX90632_REG_I2C_CMD, MLX90632_REG_I2C_CMD),
>  	regmap_reg_range(MLX90632_REG_STATUS, MLX90632_REG_STATUS),
> @@ -198,16 +218,38 @@ static const struct regmap_config mlx90632_regmap = {
>  
>  static s32 mlx90632_pwr_set_sleep_step(struct regmap *regmap)
>  {
> -	return regmap_update_bits(regmap, MLX90632_REG_CONTROL,
> -				  MLX90632_CFG_PWR_MASK,
> -				  MLX90632_PWR_STATUS_SLEEP_STEP);
> +	struct mlx90632_data *data =
> +		iio_priv(dev_get_drvdata(regmap_get_device(regmap)));
> +	s32 ret;
> +
> +	if (data->powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP)
> +		return 0;
> +
> +	ret = regmap_write_bits(regmap, MLX90632_REG_CONTROL, MLX90632_CFG_PWR_MASK,
> +				MLX90632_PWR_STATUS_SLEEP_STEP);
> +	if (ret < 0)
> +		return ret;
> +
> +	data->powerstatus = MLX90632_PWR_STATUS_SLEEP_STEP;
> +	return ret;
>  }
>  
>  static s32 mlx90632_pwr_continuous(struct regmap *regmap)
>  {
> -	return regmap_update_bits(regmap, MLX90632_REG_CONTROL,
> -				  MLX90632_CFG_PWR_MASK,
> -				  MLX90632_PWR_STATUS_CONTINUOUS);
> +	struct mlx90632_data *data =
> +		iio_priv(dev_get_drvdata(regmap_get_device(regmap)));
> +	s32 ret;
> +
> +	if (data->powerstatus == MLX90632_PWR_STATUS_CONTINUOUS)
> +		return 0;
> +
> +	ret = regmap_write_bits(regmap, MLX90632_REG_CONTROL, MLX90632_CFG_PWR_MASK,
> +				MLX90632_PWR_STATUS_CONTINUOUS);
> +	if (ret < 0)
> +		return ret;
> +
> +	data->powerstatus = MLX90632_PWR_STATUS_CONTINUOUS;
> +	return ret;
>  }
>  
>  /**
> @@ -219,6 +261,63 @@ static void mlx90632_reset_delay(void)
>  	usleep_range(150, 200);
>  }
>  
> +static int mlx90632_get_measurement_time(struct regmap *regmap, u16 meas)
> +{
> +	unsigned int reg;
> +	int ret;
> +
> +	ret = regmap_read(regmap, meas, &reg);
> +	if (ret < 0)
> +		return ret;
> +
> +	return MLX90632_MEAS_MAX_TIME >> FIELD_GET(MLX90632_EE_RR, reg);
> +}
> +
> +static int mlx90632_calculate_dataset_ready_time(struct mlx90632_data *data)
> +{
> +	unsigned int refresh_time;
> +	int ret;
> +
> +	if (data->mtyp == MLX90632_MTYP_MEDICAL) {
> +		ret = mlx90632_get_measurement_time(data->regmap,
> +						    MLX90632_EE_MEDICAL_MEAS1);
> +		if (ret < 0)
> +			return ret;
> +
> +		refresh_time = ret;
> +
> +		ret = mlx90632_get_measurement_time(data->regmap,
> +						    MLX90632_EE_MEDICAL_MEAS2);
> +		if (ret < 0)
> +			return ret;
> +
> +		refresh_time += ret;
> +	} else {
> +		ret = mlx90632_get_measurement_time(data->regmap,
> +						    MLX90632_EE_EXTENDED_MEAS1);
> +		if (ret < 0)
> +			return ret;
> +
> +		refresh_time = ret;
> +
> +		ret = mlx90632_get_measurement_time(data->regmap,
> +						    MLX90632_EE_EXTENDED_MEAS2);
> +		if (ret < 0)
> +			return ret;
> +
> +		refresh_time += ret;
> +
> +		ret = mlx90632_get_measurement_time(data->regmap,
> +						    MLX90632_EE_EXTENDED_MEAS3);
> +		if (ret < 0)
> +			return ret;
> +
> +		refresh_time += ret;
> +	}
> +
> +	return refresh_time;
> +}
> +
>  /**
>   * mlx90632_perform_measurement() - Trigger and retrieve current measurement cycle
>   * @data: pointer to mlx90632_data object containing regmap information
> @@ -249,26 +348,75 @@ static int mlx90632_perform_measurement(struct mlx90632_data *data)
>  	return (reg_status & MLX90632_STAT_CYCLE_POS) >> 2;
>  }
>  
> -static int mlx90632_set_meas_type(struct regmap *regmap, u8 type)
> +/**
> + * mlx90632_perform_measurement_burst() - Trigger and retrieve current measurement
> + * cycle in step sleep mode
> + * @data: pointer to mlx90632_data object containing regmap information
> + *
> + * Perform a measurement and return 2 as measurement cycle position reported
> + * by sensor. This is a blocking function for amount dependent on the sensor
> + * refresh rate.
> + */
> +static int mlx90632_perform_measurement_burst(struct mlx90632_data *data)
>  {
> +	unsigned int reg_status;
>  	int ret;
>  
> -	if ((type != MLX90632_MTYP_MEDICAL) && (type != MLX90632_MTYP_EXTENDED))
> -		return -EINVAL;
> +	ret = regmap_write_bits(data->regmap, MLX90632_REG_CONTROL,
> +				MLX90632_CFG_SOB_MASK, MLX90632_CFG_SOB_MASK);
> +	if (ret < 0)
> +		return ret;
>  
> -	ret = regmap_write(regmap, MLX90632_REG_I2C_CMD, MLX90632_RESET_CMD);
> +	ret = mlx90632_calculate_dataset_ready_time(data);
> +	if (ret < 0)
> +		return ret;
> +
> +	msleep(ret); /* Wait minimum time for dataset to be ready */
> +
> +	ret = regmap_read_poll_timeout(data->regmap, MLX90632_REG_STATUS,
> +				       reg_status,
> +				       (reg_status & MLX90632_STAT_BUSY) == 0,
> +				       10000, 100 * 10000);
> +	if (ret < 0) {
> +		dev_err(&data->client->dev, "data not ready");
> +		return -ETIMEDOUT;
> +	}
> +
> +	return 2;
> +}
> +
> +static int mlx90632_set_meas_type(struct mlx90632_data *data, u8 type)
> +{
> +	int current_powerstatus;
> +	int ret;
> +
> +	if (data->mtyp == type)
> +		return 0;
> +
> +	current_powerstatus = data->powerstatus;
> +	ret = mlx90632_pwr_continuous(data->regmap);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_write(data->regmap, MLX90632_REG_I2C_CMD, MLX90632_RESET_CMD);
>  	if (ret < 0)
>  		return ret;
>  
>  	mlx90632_reset_delay();
>  
> -	ret = regmap_write_bits(regmap, MLX90632_REG_CONTROL,
> +	ret = regmap_update_bits(data->regmap, MLX90632_REG_CONTROL,
>  				 (MLX90632_CFG_MTYP_MASK | MLX90632_CFG_PWR_MASK),
>  				 (MLX90632_MTYP_STATUS(type) | MLX90632_PWR_STATUS_HALT));
>  	if (ret < 0)
>  		return ret;
>  
> -	return mlx90632_pwr_continuous(regmap);
> +	data->mtyp = type;
> +	data->powerstatus = MLX90632_PWR_STATUS_HALT;
> +
> +	if (current_powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP)
> +		return mlx90632_pwr_set_sleep_step(data->regmap);
> +
> +	return mlx90632_pwr_continuous(data->regmap);
>  }
>  
>  static int mlx90632_channel_new_select(int perform_ret, uint8_t *channel_new,
> @@ -355,11 +503,30 @@ static int mlx90632_read_all_channel(struct mlx90632_data *data,
>  	s32 ret, measurement;
>  
>  	mutex_lock(&data->lock);
> -	measurement = mlx90632_perform_measurement(data);
> -	if (measurement < 0) {
> -		ret = measurement;
> +	ret = mlx90632_set_meas_type(data, MLX90632_MTYP_MEDICAL);
> +	if (ret < 0)
> +		goto read_unlock;
> +
> +	switch (data->powerstatus) {
> +	case MLX90632_PWR_STATUS_CONTINUOUS:
> +		measurement = mlx90632_perform_measurement(data);
> +		if (measurement < 0) {
> +			ret = measurement;
> +			goto read_unlock;
> +		}
> +		break;
> +	case MLX90632_PWR_STATUS_SLEEP_STEP:
> +		measurement = mlx90632_perform_measurement_burst(data);
> +		if (measurement < 0) {
> +			ret = measurement;
> +			goto read_unlock;
> +		}
> +		break;
> +	default:
> +		ret = -EOPNOTSUPP;
>  		goto read_unlock;
>  	}
> +
>  	ret = mlx90632_read_ambient_raw(data->regmap, ambient_new_raw,
>  					ambient_old_raw);
>  	if (ret < 0)
> @@ -441,14 +608,20 @@ static int mlx90632_read_all_channel_extended(struct mlx90632_data *data, s16 *o
>  	s32 ret, meas;
>  
>  	mutex_lock(&data->lock);
> -	ret = mlx90632_set_meas_type(data->regmap, MLX90632_MTYP_EXTENDED);
> +	ret = mlx90632_set_meas_type(data, MLX90632_MTYP_EXTENDED);
>  	if (ret < 0)
>  		goto read_unlock;
>  
> -	ret = read_poll_timeout(mlx90632_perform_measurement, meas, meas == 19,
> -				50000, 800000, false, data);
> -	if (ret != 0)
> -		goto read_unlock;
> +	if (data->powerstatus == MLX90632_PWR_STATUS_CONTINUOUS) {
> +		ret = read_poll_timeout(mlx90632_perform_measurement, meas, meas == 19,
> +					50000, 800000, false, data);
> +		if (ret)
> +			goto read_unlock;
> +	} else if (data->powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP) {
> +		ret = mlx90632_perform_measurement_burst(data);
> +		if (ret < 0)
> +			goto read_unlock;
> +	}
>  
>  	ret = mlx90632_read_object_raw_extended(data->regmap, object_new_raw);
>  	if (ret < 0)
> @@ -457,8 +630,6 @@ static int mlx90632_read_all_channel_extended(struct mlx90632_data *data, s16 *o
>  	ret = mlx90632_read_ambient_raw_extended(data->regmap, ambient_new_raw, ambient_old_raw);
>  
>  read_unlock:
> -	(void) mlx90632_set_meas_type(data->regmap, MLX90632_MTYP_MEDICAL);
> -
>  	mutex_unlock(&data->lock);
>  	return ret;
>  }
> @@ -743,12 +914,47 @@ static int mlx90632_calc_ambient_dsp105(struct mlx90632_data *data, int *val)
>  	return ret;
>  }
>  
> +/**
> + * mlx90632_pm_interraction_wakeup() - Measure time between user interactions to change powermode
> + * @data: pointer to mlx90632_data object containing interaction_ts information
> + *
> + * Switch to continuous mode when interaction is faster than MLX90632_MEAS_MAX_TIME. Update the
> + * interaction_ts for each function call with the jiffies to enable measurement between function
> + * calls. Initial value of the interaction_ts needs to be set before this function call.
> + */
> +static int mlx90632_pm_interraction_wakeup(struct mlx90632_data *data)
> +{
> +	unsigned long now;
> +	int ret;
> +
> +	now = jiffies;
> +	if (time_in_range(now, data->interaction_ts,
> +			  data->interaction_ts +
> +			  msecs_to_jiffies(MLX90632_MEAS_MAX_TIME + 100))) {
> +		if (data->powerstatus == MLX90632_PWR_STATUS_SLEEP_STEP) {
> +			ret = mlx90632_pwr_continuous(data->regmap);
> +			if (ret < 0)
> +				return ret;
> +		}
> +	}
> +
> +	data->interaction_ts = now;
> +
> +	return 0;
> +}
> +
>  static int mlx90632_read_raw(struct iio_dev *indio_dev,
>  			     struct iio_chan_spec const *channel, int *val,
>  			     int *val2, long mask)
>  {
>  	struct mlx90632_data *data = iio_priv(indio_dev);
>  	int ret;
> +	int cr;
> +
> +	pm_runtime_get_sync(&data->client->dev);
> +	ret = mlx90632_pm_interraction_wakeup(data);
> +	if (ret < 0)
> +		goto mlx90632_read_raw_pm;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_PROCESSED:
> @@ -756,16 +962,22 @@ static int mlx90632_read_raw(struct iio_dev *indio_dev,
>  		case IIO_MOD_TEMP_AMBIENT:
>  			ret = mlx90632_calc_ambient_dsp105(data, val);
>  			if (ret < 0)
> -				return ret;
> -			return IIO_VAL_INT;
> +				goto mlx90632_read_raw_pm;
> +
> +			ret = IIO_VAL_INT;
> +			break;
>  		case IIO_MOD_TEMP_OBJECT:
>  			ret = mlx90632_calc_object_dsp105(data, val);
>  			if (ret < 0)
> -				return ret;
> -			return IIO_VAL_INT;
> +				goto mlx90632_read_raw_pm;
> +
> +			ret = IIO_VAL_INT;
> +			break;
>  		default:
> -			return -EINVAL;
> +			ret = -EINVAL;
> +			break;
>  		}
> +		break;
>  	case IIO_CHAN_INFO_CALIBEMISSIVITY:
>  		if (data->emissivity == 1000) {
>  			*val = 1;
> @@ -774,13 +986,21 @@ static int mlx90632_read_raw(struct iio_dev *indio_dev,
>  			*val = 0;
>  			*val2 = data->emissivity * 1000;
>  		}
> -		return IIO_VAL_INT_PLUS_MICRO;
> +		ret = IIO_VAL_INT_PLUS_MICRO;
> +		break;
>  	case IIO_CHAN_INFO_CALIBAMBIENT:
>  		*val = data->object_ambient_temperature;
> -		return IIO_VAL_INT;
> +		ret = IIO_VAL_INT;
> +		break;
>  	default:
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		break;
>  	}
> +
> +mlx90632_read_raw_pm:
> +	pm_runtime_mark_last_busy(&data->client->dev);
> +	pm_runtime_put_autosuspend(&data->client->dev);
> +	return ret;
>  }
>  
>  static int mlx90632_write_raw(struct iio_dev *indio_dev,
> @@ -826,12 +1046,14 @@ static const struct iio_info mlx90632_info = {
>  	.write_raw = mlx90632_write_raw,
>  };
>  
> -static int mlx90632_sleep(struct mlx90632_data *data)
> +static void mlx90632_sleep(void *_data)
>  {
> +	struct mlx90632_data *data = _data;
> +
>  	regcache_mark_dirty(data->regmap);

This was previously in the suspend path and no longer is.
Why do we not need to deal with the regcache in the suspend any more?

Also, no longer needed here as this isn't now part of the suspend
path.

>  
>  	dev_dbg(&data->client->dev, "Requesting sleep");
> -	return mlx90632_pwr_set_sleep_step(data->regmap);
> +	mlx90632_pwr_set_sleep_step(data->regmap);
>  }
>  
>  static int mlx90632_wakeup(struct mlx90632_data *data)
> @@ -902,6 +1124,7 @@ static int mlx90632_probe(struct i2c_client *client,
>  	mlx90632->client = client;
>  	mlx90632->regmap = regmap;
>  	mlx90632->mtyp = MLX90632_MTYP_MEDICAL;
> +	mlx90632->powerstatus = MLX90632_PWR_STATUS_HALT;
>  
>  	mutex_init(&mlx90632->lock);
>  	indio_dev->name = id->name;
> @@ -933,6 +1156,13 @@ static int mlx90632_probe(struct i2c_client *client,
>  		return ret;
>  	}
>  
> +	ret = devm_add_action_or_reset(&client->dev, mlx90632_sleep, mlx90632);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Failed to setup low power cleanup action %d\n",
> +			ret);
> +		return ret;
> +	}
> +
>  	ret = regmap_read(mlx90632->regmap, MLX90632_EE_VERSION, &read);
>  	if (ret < 0) {
>  		dev_err(&client->dev, "read of version failed: %d\n", ret);
> @@ -961,34 +1191,17 @@ static int mlx90632_probe(struct i2c_client *client,
>  
>  	mlx90632->emissivity = 1000;
>  	mlx90632->object_ambient_temperature = 25000; /* 25 degrees milliCelsius */
> +	mlx90632->interaction_ts = jiffies; /* Set initial value */
>  
> -	pm_runtime_disable(&client->dev);
> -	ret = pm_runtime_set_active(&client->dev);
> -	if (ret < 0) {
> -		mlx90632_sleep(mlx90632);
> -		return ret;
> -	}
> -	pm_runtime_enable(&client->dev);
> +	pm_runtime_get_noresume(&client->dev);
> +	pm_runtime_set_active(&client->dev);
> +
> +	devm_pm_runtime_enable(&client->dev);
>  	pm_runtime_set_autosuspend_delay(&client->dev, MLX90632_SLEEP_DELAY_MS);
>  	pm_runtime_use_autosuspend(&client->dev);
> +	pm_runtime_put_autosuspend(&client->dev);
>  
> -	return iio_device_register(indio_dev);
> -}
> -
> -static int mlx90632_remove(struct i2c_client *client)
> -{
> -	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> -	struct mlx90632_data *data = iio_priv(indio_dev);
> -
> -	iio_device_unregister(indio_dev);
> -
> -	pm_runtime_disable(&client->dev);
> -	pm_runtime_set_suspended(&client->dev);
> -	pm_runtime_put_noidle(&client->dev);
> -
> -	mlx90632_sleep(data);
> -
> -	return 0;
> +	return devm_iio_device_register(&client->dev, indio_dev);
>  }
>  
>  static const struct i2c_device_id mlx90632_id[] = {
> @@ -1003,33 +1216,49 @@ static const struct of_device_id mlx90632_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, mlx90632_of_match);
>  
> -static int __maybe_unused mlx90632_pm_suspend(struct device *dev)
> +static int mlx90632_pm_suspend(struct device *dev)
>  {
> -	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> -	struct mlx90632_data *data = iio_priv(indio_dev);
> +	struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> +	int ret;
> +
> +	ret = mlx90632_pwr_set_sleep_step(data->regmap);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regulator_disable(data->regulator);
> +	if (ret < 0)
> +		dev_err(regmap_get_device(data->regmap),
> +			"Failed to disable power regulator: %d\n", ret);
>  
> -	return mlx90632_sleep(data);
> +	return ret;
>  }
>  
> -static int __maybe_unused mlx90632_pm_resume(struct device *dev)
> +static int mlx90632_pm_resume(struct device *dev)
>  {
> -	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> -	struct mlx90632_data *data = iio_priv(indio_dev);
> +	struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> +
> +	return mlx90632_enable_regulator(data);
> +}
> +
> +static int mlx90632_pm_runtime_suspend(struct device *dev)
> +{
> +	struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
>  
> -	return mlx90632_wakeup(data);
Previously we called wakeup here which writes the regcache back to
the device. Now I'm not seeing that happening anywhere in new code.
Why is it not needed?

> +	return mlx90632_pwr_set_sleep_step(data->regmap);
>  }

Re: [PATCH v5 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

[Crt Mori]

On Mon, 19 Sept 2022 at 18:24, Jonathan Cameron <jic23@kernel.org> wrote:
>
> On Mon, 19 Sep 2022 10:48:16 +0200
> cmo@melexis.com wrote:
>
> > From: Crt Mori <cmo@melexis.com>
> >
> > measurements in lower power mode (SLEEP_STEP), with the lowest refresh
> > rate (2 seconds).
> Hi Crt,
>
> I'm a little nervous about one change in the flow from earlier versions.
> I'm assuming you are sure it is always fine though!
>
> Previously before calling the _sleep() in remove we ensured the device
> was powered up. Now that's no longer true. If runtime pm has it in
> a low power state it will remain in that state at the point where we call
> _sleep().
>
> One note/question on original code...  Why bother marking regcache dirty when
> we are going down anyway?  It's not wrong as such, just probably not
> that useful unless I'm missing something.  Same in the *_wakeup()
> that puts the cache back but is only called in probe now.

Previously when powered on the device the cache was not updated, so I
added the marking of regcache at wakeup and saw that the same thing
happens when in resume after powering on. I should keep this
assumption still, so I will re-add the wakeup to resume (not runtime
resume). I did not test this part as I focused on runtime resume so
thanks for noticing.

>
> Which then raises question of why we don't need to deal with the regcache
> any more when we turn power off in suspend?
>

It just did not work properly without this. Not correct EEPROM
coefficients were used for calculations.

> So either we need a statement of why the register state is maintained,
> or add the maintenance for that.  Also probably makes sense to drop
> the left over maintenance from the probe() and remove() (via devm) paths.
>
I thought I did that by completely removing _remove() and using
devm_actions for cleanup. Do you see a spot I missed?

> Jonathan
>
> >
> > -static int __maybe_unused mlx90632_pm_resume(struct device *dev)
> > +static int mlx90632_pm_resume(struct device *dev)
> >  {
> > -     struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> > -     struct mlx90632_data *data = iio_priv(indio_dev);
> > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> > +
> > +     return mlx90632_enable_regulator(data);
> > +}
> > +
> > +static int mlx90632_pm_runtime_suspend(struct device *dev)
> > +{
> > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> >
> > -     return mlx90632_wakeup(data);
> Previously we called wakeup here which writes the regcache back to
> the device. Now I'm not seeing that happening anywhere in new code.
> Why is it not needed?
>
I had the same question before, why cache was needed to be marked
dirty, but without it, CPU did not properly obtain the calculation
coefficients. What happens now is that we are in step_sleep mode so
measurements are triggered and it also takes the 2 seconds before they
are updated. I did not check the line with scope, but I have yet to
see the strange temperature output which would indicate that not
proper EEPROM data is used. But I did focus on sleep mostly, so deeper
sleep I did not retest.

> > +     return mlx90632_pwr_set_sleep_step(data->regmap);
> >  }
>

Re: [PATCH v5 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

[Jonathan Cameron]

On Mon, 19 Sep 2022 19:09:13 +0200
Crt Mori <cmo@melexis.com> wrote:

> On Mon, 19 Sept 2022 at 18:24, Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > On Mon, 19 Sep 2022 10:48:16 +0200
> > cmo@melexis.com wrote:
> >  
> > > From: Crt Mori <cmo@melexis.com>
> > >
> > > measurements in lower power mode (SLEEP_STEP), with the lowest refresh
> > > rate (2 seconds).  
> > Hi Crt,
> >
> > I'm a little nervous about one change in the flow from earlier versions.
> > I'm assuming you are sure it is always fine though!
> >
> > Previously before calling the _sleep() in remove we ensured the device
> > was powered up. Now that's no longer true. If runtime pm has it in
> > a low power state it will remain in that state at the point where we call
> > _sleep().
> >
> > One note/question on original code...  Why bother marking regcache dirty when
> > we are going down anyway?  It's not wrong as such, just probably not
> > that useful unless I'm missing something.  Same in the *_wakeup()
> > that puts the cache back but is only called in probe now.  
> 
> Previously when powered on the device the cache was not updated

ah. Got it.  Doing this makes sense if we don't provide the default register
values as there is nothing else to get them from.

However, I think the regmap core does this for us if defaults are not provided:
https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/base/regmap/regcache.c#L180

Does that not work here for some reason?  If so add a comment.

We do need the dance in the suspend and resume though as regcache code has no
way to know if the values are retained or not so we have to let it know.

>, so I
> added the marking of regcache at wakeup and saw that the same thing
> happens when in resume after powering on. I should keep this
> assumption still, so I will re-add the wakeup to resume (not runtime
> resume). I did not test this part as I focused on runtime resume so
> thanks for noticing.
> 
> >
> > Which then raises question of why we don't need to deal with the regcache
> > any more when we turn power off in suspend?
> >  
> 
> It just did not work properly without this. Not correct EEPROM
> coefficients were used for calculations.
> 
> > So either we need a statement of why the register state is maintained,
> > or add the maintenance for that.  Also probably makes sense to drop
> > the left over maintenance from the probe() and remove() (via devm) paths.
> >  
> I thought I did that by completely removing _remove() and using
> devm_actions for cleanup. Do you see a spot I missed?
> 

I don't think marking the regcache dirty in remove (via the _sleep() call)
does anything useful.  On fresh probe of the driver, we get a new regcache which
we can then sync as you are doing - so no point in marking the one we are about
to delete as dirty that I can see.


> > Jonathan
> >  
> > >
> > > -static int __maybe_unused mlx90632_pm_resume(struct device *dev)
> > > +static int mlx90632_pm_resume(struct device *dev)
> > >  {
> > > -     struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> > > -     struct mlx90632_data *data = iio_priv(indio_dev);
> > > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> > > +
> > > +     return mlx90632_enable_regulator(data);
> > > +}
> > > +
> > > +static int mlx90632_pm_runtime_suspend(struct device *dev)
> > > +{
> > > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> > >
> > > -     return mlx90632_wakeup(data);  
> > Previously we called wakeup here which writes the regcache back to
> > the device. Now I'm not seeing that happening anywhere in new code.
> > Why is it not needed?
> >  
> I had the same question before, why cache was needed to be marked
> dirty, but without it, CPU did not properly obtain the calculation
> coefficients. What happens now is that we are in step_sleep mode so
> measurements are triggered and it also takes the 2 seconds before they
> are updated. I did not check the line with scope, but I have yet to
> see the strange temperature output which would indicate that not
> proper EEPROM data is used. But I did focus on sleep mostly, so deeper
> sleep I did not retest.

I'd hope runtime pm doesn't need the dance with the cache as the
values should be retained.  It's the deeper sleep that is where I'd
see potential problems as you observed.

Jonathan

> 
> > > +     return mlx90632_pwr_set_sleep_step(data->regmap);
> > >  }  
> >  

Re: [PATCH v5 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

[Crt Mori]

On Mon, 19 Sept 2022 at 19:30, Jonathan Cameron <jic23@kernel.org> wrote:
>
> On Mon, 19 Sep 2022 19:09:13 +0200
> Crt Mori <cmo@melexis.com> wrote:
>
> > On Mon, 19 Sept 2022 at 18:24, Jonathan Cameron <jic23@kernel.org> wrote:
> > >
> > > On Mon, 19 Sep 2022 10:48:16 +0200
> > > cmo@melexis.com wrote:
> > >
> > > > From: Crt Mori <cmo@melexis.com>
> > > >
> > > > measurements in lower power mode (SLEEP_STEP), with the lowest refresh
> > > > rate (2 seconds).
> > > Hi Crt,
> > >
> > > I'm a little nervous about one change in the flow from earlier versions.
> > > I'm assuming you are sure it is always fine though!
> > >
> > > Previously before calling the _sleep() in remove we ensured the device
> > > was powered up. Now that's no longer true. If runtime pm has it in
> > > a low power state it will remain in that state at the point where we call
> > > _sleep().
> > >
> > > One note/question on original code...  Why bother marking regcache dirty when
> > > we are going down anyway?  It's not wrong as such, just probably not
> > > that useful unless I'm missing something.  Same in the *_wakeup()
> > > that puts the cache back but is only called in probe now.
> >
> > Previously when powered on the device the cache was not updated
>
> ah. Got it.  Doing this makes sense if we don't provide the default register
> values as there is nothing else to get them from.
>
> However, I think the regmap core does this for us if defaults are not provided:
> https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/base/regmap/regcache.c#L180
>
> Does that not work here for some reason?  If so add a comment.

It did not work in past, but I can make a few tests and file a bug
later on if indeed we should not need to mark cache refresh at
startup. I would here keep it as it was, because I remember having a
big headache trying to figure out what I was missing with regmap_read
conversion (I remember I started with simple i2c reads).

>
> We do need the dance in the suspend and resume though as regcache code has no
> way to know if the values are retained or not so we have to let it know.
>
> >, so I
> > added the marking of regcache at wakeup and saw that the same thing
> > happens when in resume after powering on. I should keep this
> > assumption still, so I will re-add the wakeup to resume (not runtime
> > resume). I did not test this part as I focused on runtime resume so
> > thanks for noticing.
> >
> > >
> > > Which then raises question of why we don't need to deal with the regcache
> > > any more when we turn power off in suspend?
> > >
> >
> > It just did not work properly without this. Not correct EEPROM
> > coefficients were used for calculations.
> >
> > > So either we need a statement of why the register state is maintained,
> > > or add the maintenance for that.  Also probably makes sense to drop
> > > the left over maintenance from the probe() and remove() (via devm) paths.
> > >
> > I thought I did that by completely removing _remove() and using
> > devm_actions for cleanup. Do you see a spot I missed?
> >
>
> I don't think marking the regcache dirty in remove (via the _sleep() call)
> does anything useful.  On fresh probe of the driver, we get a new regcache which
> we can then sync as you are doing - so no point in marking the one we are about
> to delete as dirty that I can see.
>

So you would rather that I make a new function which basically will be
a wrapper around mlx90632_pwr_set_sleep_step (as I don't want to
change that function to return nothing and take a void pointer)
instead of using mlx90632_sleep in remove (beside using it in
pm_suspend after this change)?

>
> > > Jonathan
> > >
> > > >
> > > > -static int __maybe_unused mlx90632_pm_resume(struct device *dev)
> > > > +static int mlx90632_pm_resume(struct device *dev)
> > > >  {
> > > > -     struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> > > > -     struct mlx90632_data *data = iio_priv(indio_dev);
> > > > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> > > > +
> > > > +     return mlx90632_enable_regulator(data);
> > > > +}
> > > > +
> > > > +static int mlx90632_pm_runtime_suspend(struct device *dev)
> > > > +{
> > > > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> > > >
> > > > -     return mlx90632_wakeup(data);
> > > Previously we called wakeup here which writes the regcache back to
> > > the device. Now I'm not seeing that happening anywhere in new code.
> > > Why is it not needed?
> > >
> > I had the same question before, why cache was needed to be marked
> > dirty, but without it, CPU did not properly obtain the calculation
> > coefficients. What happens now is that we are in step_sleep mode so
> > measurements are triggered and it also takes the 2 seconds before they
> > are updated. I did not check the line with scope, but I have yet to
> > see the strange temperature output which would indicate that not
> > proper EEPROM data is used. But I did focus on sleep mostly, so deeper
> > sleep I did not retest.
>
> I'd hope runtime pm doesn't need the dance with the cache as the
> values should be retained.  It's the deeper sleep that is where I'd
> see potential problems as you observed.

You are correct - runtime_pm never needed any of the cache stuff.

>
> Jonathan
>
> >
> > > > +     return mlx90632_pwr_set_sleep_step(data->regmap);
> > > >  }
> > >
>

Re: [PATCH v5 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

[Jonathan Cameron]

On Mon, 19 Sep 2022 19:59:47 +0200
Crt Mori <cmo@melexis.com> wrote:

> On Mon, 19 Sept 2022 at 19:30, Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > On Mon, 19 Sep 2022 19:09:13 +0200
> > Crt Mori <cmo@melexis.com> wrote:
> >  
> > > On Mon, 19 Sept 2022 at 18:24, Jonathan Cameron <jic23@kernel.org> wrote:  
> > > >
> > > > On Mon, 19 Sep 2022 10:48:16 +0200
> > > > cmo@melexis.com wrote:
> > > >  
> > > > > From: Crt Mori <cmo@melexis.com>
> > > > >
> > > > > measurements in lower power mode (SLEEP_STEP), with the lowest refresh
> > > > > rate (2 seconds).  
> > > > Hi Crt,
> > > >
> > > > I'm a little nervous about one change in the flow from earlier versions.
> > > > I'm assuming you are sure it is always fine though!
> > > >
> > > > Previously before calling the _sleep() in remove we ensured the device
> > > > was powered up. Now that's no longer true. If runtime pm has it in
> > > > a low power state it will remain in that state at the point where we call
> > > > _sleep().
> > > >
> > > > One note/question on original code...  Why bother marking regcache dirty when
> > > > we are going down anyway?  It's not wrong as such, just probably not
> > > > that useful unless I'm missing something.  Same in the *_wakeup()
> > > > that puts the cache back but is only called in probe now.  
> > >
> > > Previously when powered on the device the cache was not updated  
> >
> > ah. Got it.  Doing this makes sense if we don't provide the default register
> > values as there is nothing else to get them from.
> >
> > However, I think the regmap core does this for us if defaults are not provided:
> > https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/base/regmap/regcache.c#L180
> >
> > Does that not work here for some reason?  If so add a comment.  
> 
> It did not work in past, but I can make a few tests and file a bug
> later on if indeed we should not need to mark cache refresh at
> startup. I would here keep it as it was, because I remember having a
> big headache trying to figure out what I was missing with regmap_read
> conversion (I remember I started with simple i2c reads).

I'd definitely like to understand if there is a problem here as it would
effect a load of other devices.

> 
> >
> > We do need the dance in the suspend and resume though as regcache code has no
> > way to know if the values are retained or not so we have to let it know.
> >  
> > >, so I
> > > added the marking of regcache at wakeup and saw that the same thing
> > > happens when in resume after powering on. I should keep this
> > > assumption still, so I will re-add the wakeup to resume (not runtime
> > > resume). I did not test this part as I focused on runtime resume so
> > > thanks for noticing.
> > >  
> > > >
> > > > Which then raises question of why we don't need to deal with the regcache
> > > > any more when we turn power off in suspend?
> > > >  
> > >
> > > It just did not work properly without this. Not correct EEPROM
> > > coefficients were used for calculations.
> > >  
> > > > So either we need a statement of why the register state is maintained,
> > > > or add the maintenance for that.  Also probably makes sense to drop
> > > > the left over maintenance from the probe() and remove() (via devm) paths.
> > > >  
> > > I thought I did that by completely removing _remove() and using
> > > devm_actions for cleanup. Do you see a spot I missed?
> > >  
> >
> > I don't think marking the regcache dirty in remove (via the _sleep() call)
> > does anything useful.  On fresh probe of the driver, we get a new regcache which
> > we can then sync as you are doing - so no point in marking the one we are about
> > to delete as dirty that I can see.
> >  
> 
> So you would rather that I make a new function which basically will be
> a wrapper around mlx90632_pwr_set_sleep_step (as I don't want to
> change that function to return nothing and take a void pointer)
> instead of using mlx90632_sleep in remove (beside using it in
> pm_suspend after this change)?

yes - it would indeed be something like you describe.

> 
> >  
> > > > Jonathan
> > > >  
> > > > >
> > > > > -static int __maybe_unused mlx90632_pm_resume(struct device *dev)
> > > > > +static int mlx90632_pm_resume(struct device *dev)
> > > > >  {
> > > > > -     struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> > > > > -     struct mlx90632_data *data = iio_priv(indio_dev);
> > > > > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> > > > > +
> > > > > +     return mlx90632_enable_regulator(data);
> > > > > +}
> > > > > +
> > > > > +static int mlx90632_pm_runtime_suspend(struct device *dev)
> > > > > +{
> > > > > +     struct mlx90632_data *data = iio_priv(dev_get_drvdata(dev));
> > > > >
> > > > > -     return mlx90632_wakeup(data);  
> > > > Previously we called wakeup here which writes the regcache back to
> > > > the device. Now I'm not seeing that happening anywhere in new code.
> > > > Why is it not needed?
> > > >  
> > > I had the same question before, why cache was needed to be marked
> > > dirty, but without it, CPU did not properly obtain the calculation
> > > coefficients. What happens now is that we are in step_sleep mode so
> > > measurements are triggered and it also takes the 2 seconds before they
> > > are updated. I did not check the line with scope, but I have yet to
> > > see the strange temperature output which would indicate that not
> > > proper EEPROM data is used. But I did focus on sleep mostly, so deeper
> > > sleep I did not retest.  
> >
> > I'd hope runtime pm doesn't need the dance with the cache as the
> > values should be retained.  It's the deeper sleep that is where I'd
> > see potential problems as you observed.  
> 
> You are correct - runtime_pm never needed any of the cache stuff.
> 
> >
> > Jonathan
> >  
> > >  
> > > > > +     return mlx90632_pwr_set_sleep_step(data->regmap);
> > > > >  }  
> > > >  
> >