drivers: icm42688: pin9 function

PIN9 of an ICM42688 can be configured as an interrupt output, external
clock input or frame sync output. Pin function can now be set via a sensor
attribute.

Signed-off-by: Yau-ming Leung <[email protected]>

Author: ymleung314

drivers/sensor/tdk/icm42688/icm42688.c

@@ -9,6 +9,7 @@
 #define DT_DRV_COMPAT invensense_icm42688
 
 #include <zephyr/drivers/sensor.h>
+#include <zephyr/drivers/sensor/icm42688.h>
 #include <zephyr/drivers/spi.h>
 #include <zephyr/sys/byteorder.h>
 
@@ -162,6 +163,29 @@ static int icm42688_attr_set(const struct device *dev, enum sensor_channel chan,
 				return -EINVAL;
 			}
 			new_config.batch_ticks = val->val1;
+		} else if ((enum sensor_attribute_icm42688)attr ==
+			   SENSOR_ATTR_ICM42688_PIN9_FUNCTION) {
+			if (val->val1 != ICM42688_PIN9_FUNCTION_INT2 &&
+			    val->val1 != ICM42688_PIN9_FUNCTION_FSYNC &&
+			    val->val1 != ICM42688_PIN9_FUNCTION_CLKIN) {
+				LOG_ERR("Unknown pin function");
+				return -EINVAL;
+			}
+
+			if (val->val2 < 31000 || val->val2 > 50000) {
+				LOG_ERR("RTC frequency must be between 31kHz and 50kHz");
+				return -EINVAL;
+			}
+
+			/* TODO: Allow this if FSYNC is configurable later. */
+			if (val->val1 == ICM42688_PIN9_FUNCTION_FSYNC) {
+				LOG_ERR("FSYNC is disabled, PIN9_FUNCTION should not be set to "
+					"FSYNC");
+				return -ENOTSUP;
+			}
+
+			new_config.pin9_function = val->val1;
+			new_config.rtc_freq = val->val2;
 		} else {
 			LOG_ERR("Unsupported attribute");
 			res = -EINVAL;
@@ -219,6 +243,10 @@ static int icm42688_attr_get(const struct device *dev, enum sensor_channel chan,
 		if (attr == SENSOR_ATTR_BATCH_DURATION) {
 			val->val1 = cfg->batch_ticks;
 			val->val2 = 0;
+		} else if ((enum sensor_attribute_icm42688)attr ==
+			   SENSOR_ATTR_ICM42688_PIN9_FUNCTION) {
+			val->val1 = cfg->pin9_function;
+			val->val2 = cfg->rtc_freq;
 		} else {
 			LOG_ERR("Unsupported attribute");
 			res = -EINVAL;
@@ -305,15 +333,17 @@ void icm42688_unlock(const struct device *dev)
 		.accel_fs = DT_INST_PROP(inst, accel_fs),		\
 		.accel_odr = DT_INST_PROP(inst, accel_odr),		\
 		.gyro_pwr_mode = DT_INST_PROP(inst, gyro_pwr_mode),	\
-		.gyro_fs = DT_INST_PROP(inst, gyro_fs),		\
+		.gyro_fs = DT_INST_PROP(inst, gyro_fs),			\
 		.gyro_odr = DT_INST_PROP(inst, gyro_odr),		\
 		.temp_dis = false,					\
 		.fifo_en = IS_ENABLED(CONFIG_ICM42688_STREAM),		\
 		.batch_ticks = 0,					\
 		.fifo_hires = false,					\
 		.interrupt1_drdy = false,				\
 		.interrupt1_fifo_ths = false,				\
-		.interrupt1_fifo_full = false				\
+		.interrupt1_fifo_full = false,				\
+		.pin9_function = ICM42688_PIN9_FUNCTION_INT2,		\
+		.rtc_freq = 32000					\
 	}
 
 #define ICM42688_DEFINE_DATA(inst)                                                                 \

drivers/sensor/tdk/icm42688/icm42688.h

@@ -308,6 +308,9 @@ struct icm42688_cfg {
 	bool interrupt1_drdy;
 	bool interrupt1_fifo_ths;
 	bool interrupt1_fifo_full;
+
+	uint8_t pin9_function;
+	uint16_t rtc_freq;
 };
 
 struct icm42688_trigger_entry {

drivers/sensor/tdk/icm42688/icm42688_common.c

@@ -7,6 +7,7 @@
  */
 
 #include <zephyr/drivers/sensor.h>
+#include <zephyr/drivers/sensor/icm42688.h>
 #include <zephyr/drivers/spi.h>
 #include <zephyr/sys/byteorder.h>
 #include "icm42688.h"
@@ -148,6 +149,41 @@ int icm42688_configure(const struct device *dev, struct icm42688_cfg *cfg)
 
 	/* TODO maybe do the next few steps intelligently by checking current config */
 
+	/* Select register bank 1 */
+	res = icm42688_spi_single_write(&dev_cfg->spi, REG_BANK_SEL, BIT_BANK1);
+	if (res != 0) {
+		LOG_ERR("Error selecting register bank 1");
+		return -EINVAL;
+	}
+
+	/* Set pin 9 function */
+	uint8_t intf_config5 = FIELD_PREP(MASK_PIN9_FUNCTION, cfg->pin9_function);
+
+	LOG_DBG("INTF_CONFIG5 (0x%lx) 0x%x", FIELD_GET(REG_ADDRESS_MASK, REG_INTF_CONFIG5),
+		intf_config5);
+	res = icm42688_spi_single_write(&dev_cfg->spi, REG_INTF_CONFIG5, intf_config5);
+	if (res != 0) {
+		LOG_ERR("Error writing INTF_CONFIG5");
+		return -EINVAL;
+	}
+
+	/* Select register bank 0 */
+	res = icm42688_spi_single_write(&dev_cfg->spi, REG_BANK_SEL, BIT_BANK0);
+	if (res != 0) {
+		LOG_ERR("Error selecting register bank 0");
+		return -EINVAL;
+	}
+
+	bool is_pin9_clkin = cfg->pin9_function == ICM42688_PIN9_FUNCTION_CLKIN;
+	uint8_t intf_config1 = 0x91 | FIELD_PREP(BIT_RTC_MODE, is_pin9_clkin);
+
+	LOG_DBG("INTF_CONFIG1 (0x%x) 0x%x", REG_INTF_CONFIG1, intf_config1);
+	res = icm42688_spi_single_write(&dev_cfg->spi, REG_INTF_CONFIG1, intf_config1);
+	if (res != 0) {
+		LOG_ERR("Error writing INTF_CONFIG1");
+		return -EINVAL;
+	}
+
 	/* Power management to set gyro/accel modes */
 	uint8_t pwr_mgmt0 = FIELD_PREP(MASK_GYRO_MODE, cfg->gyro_pwr_mode) |
 			    FIELD_PREP(MASK_ACCEL_MODE, cfg->accel_pwr_mode) |

drivers/sensor/tdk/icm42688/icm42688_decoder.c

@@ -319,6 +319,28 @@ static uint32_t gyro_period_ns[] = {
 	[ICM42688_DT_GYRO_ODR_32000] = UINT32_C(1000000) / 32,
 };
 
+static int icm42688_calc_timestamp_delta(int rtc_freq, int chan_type, int dt_odr, int frame_count,
+					 uint64_t *out_delta)
+{
+	uint32_t period;
+
+	if (IS_ACCEL(chan_type)) {
+		period = accel_period_ns[dt_odr];
+	} else if (IS_GYRO(chan_type)) {
+		period = gyro_period_ns[dt_odr];
+	} else {
+		return -EINVAL;
+	}
+
+	/*
+	 * When ODR is set to r and an external clock with frequency f is used,
+	 * the actual ODR = f * r / 32000.
+	 */
+	*out_delta = (uint64_t)period * frame_count * 32000 / rtc_freq;
+
+	return 0;
+}
+
 static int icm42688_fifo_decode(const uint8_t *buffer, struct sensor_chan_spec chan_spec,
 				uint32_t *fit, uint16_t max_count, void *data_out)
 {
@@ -363,27 +385,66 @@ static int icm42688_fifo_decode(const uint8_t *buffer, struct sensor_chan_spec c
 		}
 		if (chan_spec.chan_type == SENSOR_CHAN_DIE_TEMP) {
 			struct sensor_q31_data *data = (struct sensor_q31_data *)data_out;
+			uint64_t ts_delta;
 
-			data->shift = 9;
 			if (has_accel) {
-				data->readings[count].timestamp_delta =
-					accel_period_ns[edata->accel_odr] * (accel_frame_count - 1);
+				rc = icm42688_calc_timestamp_delta(
+					edata->rtc_freq, SENSOR_CHAN_ACCEL_XYZ, edata->accel_odr,
+					accel_frame_count - 1, &ts_delta);
 			} else {
-				data->readings[count].timestamp_delta =
-					gyro_period_ns[edata->gyro_odr] * (gyro_frame_count - 1);
+				rc = icm42688_calc_timestamp_delta(
+					edata->rtc_freq, SENSOR_CHAN_GYRO_XYZ, edata->gyro_odr,
+					gyro_frame_count - 1, &ts_delta);
+			}
+			if (rc < 0) {
+				buffer = frame_end;
+				continue;
+			}
+
+			/*
+			 * TODO: For some extreme combination of ODR and FIFO count, using uint32_t
+			 * to store timestamp delta will overflow. Better error reporting?
+			 */
+			if (ts_delta > UINT32_MAX) {
+				LOG_ERR("Timestamp delta overflow");
+				buffer = frame_end;
+				continue;
 			}
+
+			data->readings[count].timestamp_delta = ts_delta;
+
+			data->shift = 9;
 			data->readings[count].temperature =
 				icm42688_read_temperature_from_packet(buffer);
 		} else if (IS_ACCEL(chan_spec.chan_type) && has_accel) {
 			/* Decode accel */
 			struct sensor_three_axis_data *data =
 				(struct sensor_three_axis_data *)data_out;
-			uint64_t period_ns = accel_period_ns[edata->accel_odr];
+			uint64_t ts_delta;
 
 			icm42688_get_shift(SENSOR_CHAN_ACCEL_XYZ, edata->header.accel_fs,
 					   edata->header.gyro_fs, &data->shift);
 
-			data->readings[count].timestamp_delta = (accel_frame_count - 1) * period_ns;
+			rc = icm42688_calc_timestamp_delta(edata->rtc_freq, SENSOR_CHAN_ACCEL_XYZ,
+							   edata->accel_odr, accel_frame_count - 1,
+							   &ts_delta);
+			if (rc < 0) {
+				buffer = frame_end;
+				continue;
+			}
+
+			/*
+			 * TODO: For some extreme combination of ODR and FIFO count, using uint32_t
+			 * to store timestamp delta will overflow. Better error reporting?
+			 */
+			if (ts_delta > UINT32_MAX) {
+				LOG_ERR("Timestamp delta overflow");
+				buffer = frame_end;
+				continue;
+			}
+
+			data->readings[count].timestamp_delta = ts_delta;
+
 			rc = icm42688_read_imu_from_packet(buffer, true, edata->header.accel_fs, 0,
 							   &data->readings[count].x);
 			rc |= icm42688_read_imu_from_packet(buffer, true, edata->header.accel_fs, 1,
@@ -399,12 +460,31 @@ static int icm42688_fifo_decode(const uint8_t *buffer, struct sensor_chan_spec c
 			/* Decode gyro */
 			struct sensor_three_axis_data *data =
 				(struct sensor_three_axis_data *)data_out;
-			uint64_t period_ns = gyro_period_ns[edata->gyro_odr];
+			uint64_t ts_delta;
 
 			icm42688_get_shift(SENSOR_CHAN_GYRO_XYZ, edata->header.accel_fs,
 					   edata->header.gyro_fs, &data->shift);
 
-			data->readings[count].timestamp_delta = (gyro_frame_count - 1) * period_ns;
+			rc = icm42688_calc_timestamp_delta(edata->rtc_freq, SENSOR_CHAN_GYRO_XYZ,
+							   edata->gyro_odr, gyro_frame_count - 1,
+							   &ts_delta);
+			if (rc < 0) {
+				buffer = frame_end;
+				continue;
+			}
+
+			/*
+			 * TODO: For some extreme combination of ODR and FIFO count, using uint32_t
+			 * to store timestamp delta will overflow. Better error reporting?
+			 */
+			if (ts_delta > UINT32_MAX) {
+				LOG_ERR("Timestamp delta overflow");
+				buffer = frame_end;
+				continue;
+			}
+
+			data->readings[count].timestamp_delta = ts_delta;
+
 			rc = icm42688_read_imu_from_packet(buffer, false, edata->header.gyro_fs, 0,
 							   &data->readings[count].x);
 			rc |= icm42688_read_imu_from_packet(buffer, false, edata->header.gyro_fs, 1,

drivers/sensor/tdk/icm42688/icm42688_decoder.h

@@ -21,10 +21,11 @@ struct icm42688_decoder_header {
 struct icm42688_fifo_data {
 	struct icm42688_decoder_header header;
 	uint8_t int_status;
-	uint16_t gyro_odr: 4;
-	uint16_t accel_odr: 4;
+	uint8_t gyro_odr: 4;
+	uint8_t accel_odr: 4;
 	uint16_t fifo_count: 11;
-	uint16_t reserved: 5;
+	uint16_t padding1: 5;
+	uint16_t rtc_freq;
 } __attribute__((__packed__));
 
 struct icm42688_encoded_data {

drivers/sensor/tdk/icm42688/icm42688_reg.h

@@ -276,6 +276,9 @@
 #define BIT_INT_TDEASSERT_DISABLE BIT(5)
 #define BIT_INT_ASYNC_RESET	  BIT(4)
 
+/* Bank1 REG_INTF_CONFIG5 */
+#define MASK_PIN9_FUNCTION GENMASK(2, 1)
+
 /* misc. defines */
 #define WHO_AM_I_ICM42688     0x47
 #define MIN_ACCEL_SENS_SHIFT  11

drivers/sensor/tdk/icm42688/icm42688_rtio_stream.c

@@ -118,6 +118,7 @@ static void icm42688_fifo_count_cb(struct rtio *r, const struct rtio_sqe *sqe, v
 		.int_status = drv_data->int_status,
 		.gyro_odr = drv_data->cfg.gyro_odr,
 		.accel_odr = drv_data->cfg.accel_odr,
+		.rtc_freq = drv_data->cfg.rtc_freq,
 	};
 	uint32_t buf_avail = buf_len;
 

include/zephyr/drivers/sensor/icm42688.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright The Zephyr Project Contributors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_DRIVERS_SENSOR_ICM42688_H_
+#define ZEPHYR_INCLUDE_DRIVERS_SENSOR_ICM42688_H_
+
+#include <zephyr/drivers/sensor.h>
+
+/**
+ * @file
+ * @brief Extended public API for ICM42688
+ *
+ * Pin function configuration via attributes under the current sensor driver abstraction.
+ */
+
+#define ICM42688_PIN9_FUNCTION_INT2  0
+#define ICM42688_PIN9_FUNCTION_FSYNC 1
+#define ICM42688_PIN9_FUNCTION_CLKIN 2
+
+/**
+ * @brief Extended sensor attributes for ICM42688
+ *
+ * Attributes for setting pin function.
+ */
+enum sensor_attribute_icm42688 {
+	SENSOR_ATTR_ICM42688_PIN9_FUNCTION = SENSOR_ATTR_PRIV_START
+};
+
+#endif /* ZEPHYR_INCLUDE_DRIVERS_SENSOR_ICM42688_H_ */