Re: [PATCH v6 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

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Le 22/09/2022 à 10:13, cmo-fc6wVz46lShBDgjK7y7TUQ@xxxxxxxxxxxxxxxx a écrit :
From: Crt Mori <cmo-fc6wVz46lShBDgjK7y7TUQ@xxxxxxxxxxxxxxxx>

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,

should there be a v7, a few nitpick below.


Signed-off-by: Crt Mori <cmo-fc6wVz46lShBDgjK7y7TUQ@xxxxxxxxxxxxxxxx>
---
  drivers/iio/temperature/mlx90632.c | 379 +++++++++++++++++++++++------
  1 file changed, 309 insertions(+), 70 deletions(-)

diff --git a/drivers/iio/temperature/mlx90632.c b/drivers/iio/temperature/mlx90632.c
index 549c0ab5c2be..71130d237a69 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)

Not related to this patch, but why s32 and not int?
It would be more in line with places where this function is used.

  {
-	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;

return 0; ?

  }
static s32 mlx90632_pwr_continuous(struct regmap *regmap)

Not related to this patch, but why s32 and not int?
It would be more in line with places where this function is used.

  {
-	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;

return 0; ?

  }
/**
@@ -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;

Why not "return ret;"?

+	}
+
+	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);

  ret = mlx90632_perform_measurement(data);
and
  measurement = ret;
on success would be less verbose (no need for {}, and save 1 LoC) and more in line with mlx90632_calculate_dataset_ready_time() above.

+		if (measurement < 0) {
+			ret = measurement;
+			goto read_unlock;
+		}
+		break;
+	case MLX90632_PWR_STATUS_SLEEP_STEP:
+		measurement = mlx90632_perform_measurement_burst(data);

Same.

+		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;

This 'cr' seems to be unused.

+
+	pm_runtime_get_sync(&data->client->dev);
+	ret = mlx90632_pm_interraction_wakeup(data);
+	if (ret < 0)
+		goto mlx90632_read_raw_pm;

[...]



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