drivers: sensor: Add driver for SB-TSI

Add a driver for the SB Temperature Sensor Interface. This is an I2C
temperature sensor on AMD SoCs.

Signed-off-by: Paweł Anikiel <[email protected]>

drivers/sensor/CMakeLists.txt

@@ -9,6 +9,7 @@ add_subdirectory_ifdef(CONFIG_ADXL362 adxl362)
 add_subdirectory_ifdef(CONFIG_ADXL372 adxl372)
 add_subdirectory_ifdef(CONFIG_AK8975 ak8975)
 add_subdirectory_ifdef(CONFIG_AKM09918C akm09918c)
+add_subdirectory_ifdef(CONFIG_AMD_SB_TSI amd_sb_tsi)
 add_subdirectory_ifdef(CONFIG_AMG88XX amg88xx)
 add_subdirectory_ifdef(CONFIG_AMS_AS5600 ams_as5600)
 add_subdirectory_ifdef(CONFIG_AMS_IAQ_CORE ams_iAQcore)

drivers/sensor/Kconfig

@@ -65,6 +65,7 @@ source "drivers/sensor/adxl362/Kconfig"
 source "drivers/sensor/adxl372/Kconfig"
 source "drivers/sensor/ak8975/Kconfig"
 source "drivers/sensor/akm09918c/Kconfig"
+source "drivers/sensor/amd_sb_tsi/Kconfig"
 source "drivers/sensor/amg88xx/Kconfig"
 source "drivers/sensor/ams_as5600/Kconfig"
 source "drivers/sensor/ams_iAQcore/Kconfig"

drivers/sensor/amd_sb_tsi/CMakeLists.txt

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+zephyr_library_sources(sb_tsi.c)
+zephyr_library_sources_ifdef(CONFIG_EMUL_AMD_SB_TSI sb_tsi_emul.c)

drivers/sensor/amd_sb_tsi/Kconfig

@@ -0,0 +1,21 @@
+# SB-TSI configuration options
+
+# Copyright (c) 2023 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config AMD_SB_TSI
+	bool "AMD SB Temperature Sensor Interface"
+	default y
+	depends on DT_HAS_AMD_SB_TSI_ENABLED
+	select I2C
+	help
+	  Enable the driver for SB Temperature Sensor Interface. This
+	  is an I2C temperature sensor on AMD SoCs.
+
+config EMUL_AMD_SB_TSI
+	bool "Emulator for AMD SB-TSI"
+	default y
+	depends on AMD_SB_TSI
+	depends on EMUL
+	help
+	  Enable the hardware emulator for the AMD SB-TSI.

drivers/sensor/amd_sb_tsi/sb_tsi.c

@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2023 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT amd_sb_tsi
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/pm/device.h>
+#include <zephyr/pm/device_runtime.h>
+#include <zephyr/logging/log.h>
+#include "sb_tsi.h"
+
+LOG_MODULE_REGISTER(AMD_SB_TSI, CONFIG_SENSOR_LOG_LEVEL);
+
+static int sb_tsi_sample_fetch(const struct device *dev,
+			       enum sensor_channel chan)
+{
+	struct sb_tsi_data *data = dev->data;
+	const struct sb_tsi_config *config = dev->config;
+	int res;
+
+	if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_DIE_TEMP) {
+		return -ENOTSUP;
+	}
+
+	res = pm_device_runtime_get(dev);
+	if (res) {
+		return res;
+	}
+
+	/*
+	 * ReadOrder specifies the order for atomically reading the temp.
+	 * The reset value is 0, which means reading Int latches Dec.
+	 */
+	res = i2c_reg_read_byte_dt(&config->i2c, SB_TSI_TEMP_INT, &data->sample_int);
+	if (!res) {
+		res = i2c_reg_read_byte_dt(&config->i2c, SB_TSI_TEMP_DEC, &data->sample_dec);
+	}
+
+	(void)pm_device_runtime_put(dev);
+
+	return res;
+}
+
+static int sb_tsi_channel_get(const struct device *dev,
+			      enum sensor_channel chan,
+			      struct sensor_value *val)
+{
+	struct sb_tsi_data *data = dev->data;
+
+	if (chan != SENSOR_CHAN_DIE_TEMP) {
+		return -ENOTSUP;
+	}
+
+	val->val1 = data->sample_int;
+	val->val2 = (data->sample_dec >> SB_TSI_TEMP_DEC_SHIFT) *
+		    (1000000 / SB_TSI_TEMP_DEC_SCALE);
+
+	return 0;
+}
+
+static const struct sensor_driver_api sb_tsi_driver_api = {
+	.sample_fetch = sb_tsi_sample_fetch,
+	.channel_get = sb_tsi_channel_get,
+};
+
+static int sb_tsi_init(const struct device *dev)
+{
+	const struct sb_tsi_config *config = dev->config;
+	int res = 0;
+
+	if (!i2c_is_ready_dt(&config->i2c)) {
+		LOG_ERR("I2C device not ready");
+		return -ENODEV;
+	}
+
+#ifdef CONFIG_PM_DEVICE_RUNTIME
+	pm_device_init_suspended(dev);
+
+	res = pm_device_runtime_enable(dev);
+	if (res) {
+		LOG_ERR("Failed to enable runtime power management");
+	}
+#endif
+
+	return res;
+}
+
+#ifdef CONFIG_PM_DEVICE
+static int sb_tsi_pm_action(const struct device *dev, enum pm_device_action action)
+{
+	switch (action) {
+	case PM_DEVICE_ACTION_TURN_ON:
+	case PM_DEVICE_ACTION_RESUME:
+	case PM_DEVICE_ACTION_TURN_OFF:
+	case PM_DEVICE_ACTION_SUSPEND:
+		return 0;
+	default:
+		return -ENOTSUP;
+	}
+}
+#endif
+
+#define SB_TSI_INST(inst)								\
+	static struct sb_tsi_data sb_tsi_data_##inst;					\
+	static const struct sb_tsi_config sb_tsi_config_##inst = {			\
+		.i2c = I2C_DT_SPEC_INST_GET(inst),					\
+	};										\
+	PM_DEVICE_DT_INST_DEFINE(inst, sb_tsi_pm_action);				\
+	SENSOR_DEVICE_DT_INST_DEFINE(inst, sb_tsi_init, PM_DEVICE_DT_INST_GET(inst),	\
+			      &sb_tsi_data_##inst, &sb_tsi_config_##inst, POST_KERNEL,	\
+			      CONFIG_SENSOR_INIT_PRIORITY, &sb_tsi_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(SB_TSI_INST)

drivers/sensor/amd_sb_tsi/sb_tsi.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2023 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_DRIVERS_SENSOR_SB_TSI_SB_TSI_H_
+#define ZEPHYR_DRIVERS_SENSOR_SB_TSI_SB_TSI_H_
+
+#include <zephyr/device.h>
+#include <zephyr/sys/util.h>
+
+#define SB_TSI_TEMP_INT 0x01
+#define SB_TSI_TEMP_DEC 0x10
+#define SB_TSI_TEMP_DEC_SHIFT 5
+#define SB_TSI_TEMP_DEC_SCALE 8
+
+struct sb_tsi_data {
+	uint8_t sample_int;
+	uint8_t sample_dec;
+};
+
+struct sb_tsi_config {
+	struct i2c_dt_spec i2c;
+};
+
+#endif

drivers/sensor/amd_sb_tsi/sb_tsi_emul.c

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2023 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT amd_sb_tsi
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/emul.h>
+#include <zephyr/drivers/emul_sensor.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/i2c_emul.h>
+#include <zephyr/logging/log.h>
+#include "sb_tsi.h"
+
+LOG_MODULE_DECLARE(AMD_SB_TSI, CONFIG_SENSOR_LOG_LEVEL);
+
+#define NUM_REGS 128
+
+struct sb_tsi_emul_data {
+	uint8_t reg[NUM_REGS];
+};
+
+struct sb_tsi_emul_cfg {
+};
+
+static void sb_tsi_emul_set_reg(const struct emul *target, uint8_t reg, uint8_t val)
+{
+	struct sb_tsi_emul_data *data = target->data;
+
+	__ASSERT_NO_MSG(reg < NUM_REGS);
+	data->reg[reg] = val;
+}
+
+static uint8_t sb_tsi_emul_get_reg(const struct emul *target, uint8_t reg)
+{
+	struct sb_tsi_emul_data *data = target->data;
+
+	__ASSERT_NO_MSG(reg < NUM_REGS);
+	return data->reg[reg];
+}
+
+static void sb_tsi_emul_reset(const struct emul *target)
+{
+	struct sb_tsi_emul_data *data = target->data;
+
+	memset(data->reg, 0, NUM_REGS);
+}
+
+static int sb_tsi_emul_transfer_i2c(const struct emul *target, struct i2c_msg *msgs,
+				    int num_msgs, int addr)
+{
+	/* Largely copied from emul_bmi160.c */
+	unsigned int val;
+	int reg;
+
+	__ASSERT_NO_MSG(msgs && num_msgs);
+
+	i2c_dump_msgs_rw("emul", msgs, num_msgs, addr, false);
+	switch (num_msgs) {
+	case 2:
+		if (msgs->flags & I2C_MSG_READ) {
+			LOG_ERR("Unexpected read");
+			return -EIO;
+		}
+		if (msgs->len != 1) {
+			LOG_ERR("Unexpected msg0 length %d", msgs->len);
+			return -EIO;
+		}
+		reg = msgs->buf[0];
+
+		/* Now process the 'read' part of the message */
+		msgs++;
+		if (msgs->flags & I2C_MSG_READ) {
+			switch (msgs->len) {
+			case 1:
+				val = sb_tsi_emul_get_reg(target, reg);
+				msgs->buf[0] = val;
+				break;
+			default:
+				LOG_ERR("Unexpected msg1 length %d", msgs->len);
+				return -EIO;
+			}
+		} else {
+			if (msgs->len != 1) {
+				LOG_ERR("Unexpected msg1 length %d", msgs->len);
+			}
+			sb_tsi_emul_set_reg(target, reg, msgs->buf[0]);
+		}
+		break;
+	default:
+		LOG_ERR("Invalid number of messages: %d", num_msgs);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int sb_tsi_emul_init(const struct emul *target, const struct device *parent)
+{
+	sb_tsi_emul_reset(target);
+	return 0;
+}
+
+static int sb_tsi_emul_set_channel(const struct emul *target, enum sensor_channel chan,
+				   q31_t value, int8_t shift)
+{
+	struct sb_tsi_emul_data *data = target->data;
+	int64_t scaled_value;
+	int32_t millicelsius;
+	int32_t reg_value;
+
+	if (chan != SENSOR_CHAN_DIE_TEMP) {
+		return -ENOTSUP;
+	}
+
+	scaled_value = (int64_t)value << shift;
+	millicelsius = scaled_value * 1000 / ((int64_t)INT32_MAX + 1);
+	reg_value = CLAMP(millicelsius / 125, 0, 0x7ff);
+
+	data->reg[SB_TSI_TEMP_INT] = reg_value >> 3;
+	data->reg[SB_TSI_TEMP_DEC] = (reg_value & 0x7) << 5;
+
+	return 0;
+}
+
+static int sb_tsi_emul_get_sample_range(const struct emul *target, enum sensor_channel chan,
+					q31_t *lower, q31_t *upper, q31_t *epsilon, int8_t *shift)
+{
+	if (chan != SENSOR_CHAN_DIE_TEMP) {
+		return -ENOTSUP;
+	}
+
+	*shift = 8;
+	*lower = 0;
+	*upper = (int64_t)(255.875 * ((int64_t)INT32_MAX + 1)) >> *shift;
+	*epsilon = (int64_t)(0.125 * ((int64_t)INT32_MAX + 1)) >> *shift;
+
+	return 0;
+}
+
+static const struct i2c_emul_api sb_tsi_emul_api_i2c = {
+	.transfer = sb_tsi_emul_transfer_i2c,
+};
+
+static const struct emul_sensor_backend_api sb_tsi_emul_api_sensor = {
+	.set_channel = sb_tsi_emul_set_channel,
+	.get_sample_range = sb_tsi_emul_get_sample_range,
+};
+
+#define SB_TSI_EMUL(n)								\
+	const struct sb_tsi_emul_cfg sb_tsi_emul_cfg_##n;			\
+	struct sb_tsi_emul_data sb_tsi_emul_data_##n;				\
+	EMUL_DT_INST_DEFINE(n, sb_tsi_emul_init, &sb_tsi_emul_data_##n,		\
+			    &sb_tsi_emul_cfg_##n, &sb_tsi_emul_api_i2c,		\
+			    &sb_tsi_emul_api_sensor)
+
+DT_INST_FOREACH_STATUS_OKAY(SB_TSI_EMUL)

dts/bindings/sensor/amd,sb-tsi.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2023 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+description: AMD SB Temperature Sensor Interface.
+
+compatible: "amd,sb-tsi"
+
+include: [sensor-device.yaml, i2c-device.yaml]

tests/drivers/build_all/sensor/i2c.dtsi

@@ -744,3 +744,8 @@ test_i2c_ist8310@6f {
 	reg = <0x6f>;
 	status = "okay";
 };
+
+test_i2c_amd_sb_tsi: amd_sb_tsi@70 {
+	compatible = "amd,sb-tsi";
+	reg = <0x70>;
+};