fuel_gauge: Sample sbs gauge driver with tests

Add a sample sbs gauge driver with feature parity and basic tests
comparison to its sensor counter-part. Includes a simple stub test that is
extended upon.

Signed-off-by: Aaron Massey <aaronmassey@google.com>

drivers/CMakeLists.txt

@@ -73,3 +73,4 @@ add_subdirectory_ifdef(CONFIG_BOARD_XENVM xen)
 add_subdirectory_ifdef(CONFIG_MM_DRV           mm)
 add_subdirectory_ifdef(CONFIG_RESET          reset)
 add_subdirectory_ifdef(CONFIG_COREDUMP_DEVICE  coredump)
+add_subdirectory_ifdef(CONFIG_FUEL_GAUGE  fuel_gauge)

drivers/Kconfig

@@ -149,4 +149,6 @@ source "drivers/coredump/Kconfig"
 
 source "drivers/xen/Kconfig"
 
+source "drivers/fuel_gauge/Kconfig"
+
 endmenu

drivers/fuel_gauge/CMakeLists.txt

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: Apache-2.0
+
+add_subdirectory_ifdef(CONFIG_SBS_GAUGE_NEW_API		sbs_gauge)

drivers/fuel_gauge/Kconfig

@@ -0,0 +1,18 @@
+# Copyright 2022 Google LLC
+#
+# SPDX-License-Identifier: Apache-2.0
+
+menuconfig FUEL_GAUGE
+	bool "Battery fuel gauge drivers"
+	help
+	  Enable battery fuel gauge driver configuration.
+
+if FUEL_GAUGE
+
+module = FUEL_GAUGE
+module-str = fuel_gauge
+source "subsys/logging/Kconfig.template.log_config"
+
+source "drivers/fuel_gauge/sbs_gauge/Kconfig"
+
+endif # FUEL_GAUGE

drivers/fuel_gauge/sbs_gauge/CMakeLists.txt

@@ -0,0 +1,3 @@
+zephyr_library()
+
+zephyr_library_sources(sbs_gauge.c)

drivers/fuel_gauge/sbs_gauge/Kconfig

@@ -0,0 +1,10 @@
+# Copyright (c) 2021 Leica Geosystems AG
+# SPDX-License-Identifier: Apache-2.0
+
+config SBS_GAUGE_NEW_API
+	bool "Smart Battery Fuel Gauge"
+	default y
+	depends on DT_HAS_SBS_SBS_GAUGE_NEW_API_ENABLED
+	select I2C
+	help
+	  Enable I2C-based/SMBus-based driver for a Smart Battery Fuel Gauge.

drivers/fuel_gauge/sbs_gauge/sbs_gauge.c

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2022 Leica Geosystems AG
+ *
+ * Copyright 2022 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT sbs_sbs_gauge_new_api
+
+#include "sbs_gauge.h"
+
+#include <zephyr/drivers/fuel_gauge.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/sys/byteorder.h>
+
+LOG_MODULE_REGISTER(sbs_gauge);
+
+static int sbs_cmd_reg_read(const struct device *dev, uint8_t reg_addr, uint16_t *val)
+{
+	const struct sbs_gauge_config *cfg;
+	uint8_t i2c_data[2];
+	int status;
+
+	cfg = dev->config;
+	status = i2c_burst_read_dt(&cfg->i2c, reg_addr, i2c_data, ARRAY_SIZE(i2c_data));
+	if (status < 0) {
+		LOG_ERR("Unable to read register");
+		return status;
+	}
+
+	*val = sys_get_le16(i2c_data);
+
+	return 0;
+}
+
+static int sbs_gauge_get_prop(const struct device *dev, struct fuel_gauge_get_property *prop)
+{
+	int rc = 0;
+	uint16_t val = 0;
+
+	switch (prop->property_type) {
+	case FUEL_GAUGE_AVG_CURRENT:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_AVG_CURRENT, &val);
+		prop->value.avg_current = val * 1000;
+		break;
+	case FUEL_GAUGE_CYCLE_COUNT:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_CYCLE_COUNT, &val);
+		prop->value.cycle_count = val;
+		break;
+	case FUEL_GAUGE_CURRENT:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_CURRENT, &val);
+		prop->value.current = val * 1000;
+		break;
+	case FUEL_GAUGE_FULL_CHARGE_CAPACITY:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_FULL_CAPACITY, &val);
+		prop->value.full_charge_capacity = val * 1000;
+		break;
+	case FUEL_GAUGE_REMAINING_CAPACITY:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_REM_CAPACITY, &val);
+		prop->value.remaining_capacity = val * 1000;
+		break;
+	case FUEL_GAUGE_RUNTIME_TO_EMPTY:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_RUNTIME2EMPTY, &val);
+		prop->value.runtime_to_empty = val;
+		break;
+	case FUEL_GAUGE_RUNTIME_TO_FULL:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_AVG_TIME2FULL, &val);
+		prop->value.runtime_to_empty = val;
+		break;
+	case FUEL_GAUGE_STATE_OF_CHARGE:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_ASOC, &val);
+		prop->value.state_of_charge = val;
+		break;
+	case FUEL_GAUGE_TEMPERATURE:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_TEMP, &val);
+		prop->value.temperature = val;
+		break;
+	case FUEL_GAUGE_VOLTAGE:
+		rc = sbs_cmd_reg_read(dev, SBS_GAUGE_CMD_VOLTAGE, &val);
+		prop->value.voltage = val * 1000;
+		break;
+	default:
+		rc = -ENOTSUP;
+	}
+
+	prop->status = rc;
+
+	return rc;
+}
+
+static int sbs_gauge_get_props(const struct device *dev, struct fuel_gauge_get_property *props,
+			       size_t len)
+{
+	int ret = 0;
+
+	for (int i = 0; i < len; i++) {
+		ret |= sbs_gauge_get_prop(dev, props + i);
+	}
+
+	return ret;
+}
+
+/**
+ * @brief initialize the fuel gauge
+ *
+ * @return 0 for success
+ */
+static int sbs_gauge_init(const struct device *dev)
+{
+	const struct sbs_gauge_config *cfg;
+
+	cfg = dev->config;
+
+	if (!device_is_ready(cfg->i2c.bus)) {
+		LOG_ERR("Bus device is not ready");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static const struct battery_driver_api sbs_gauge_driver_api = {
+	.get_property = &sbs_gauge_get_props,
+};
+
+/* FIXME: fix init priority */
+#define SBS_GAUGE_INIT(index)                                                                      \
+                                                                                                   \
+	static const struct sbs_gauge_config sbs_gauge_config_##index = {                          \
+		.i2c = I2C_DT_SPEC_INST_GET(index),                                                \
+	};                                                                                         \
+                                                                                                   \
+	DEVICE_DT_INST_DEFINE(index, &sbs_gauge_init, NULL, NULL, &sbs_gauge_config_##index,       \
+			      POST_KERNEL, 90, &sbs_gauge_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(SBS_GAUGE_INIT)

drivers/fuel_gauge/sbs_gauge/sbs_gauge.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2021 Leica Geosystems AG
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_DRIVERS_SENSOR_SBS_GAUGE_H_
+#define ZEPHYR_DRIVERS_SENSOR_SBS_GAUGE_H_
+
+#include <stdint.h>
+#include <zephyr/drivers/i2c.h>
+
+/** Standard Commands */
+#define SBS_GAUGE_CMD_MANUFACTURER_ACCESS   0x00 /* ManufacturerAccess */
+#define SBS_GAUGE_CMD_REM_CAPACITY_ALARM    0x01 /* LowCapacityAlarmThreshold */
+#define SBS_GAUGE_CMD_REM_TIME_ALARM        0x02 /* RemainingTimeToEmptyThreshold */
+#define SBS_GAUGE_CMD_BATTERY_MODE          0x03 /* BatteryOperatingMode */
+#define SBS_GAUGE_CMD_AR                    0x04 /* AtRate */
+#define SBS_GAUGE_CMD_ARTTF                 0x05 /* AtRateTimeToFull */
+#define SBS_GAUGE_CMD_ARTTE                 0x06 /* AtRateTimeToEmpty */
+#define SBS_GAUGE_CMD_AROK                  0x07 /* AtRateOK */
+#define SBS_GAUGE_CMD_TEMP                  0x08 /* Temperature */
+#define SBS_GAUGE_CMD_VOLTAGE               0x09 /* Voltage */
+#define SBS_GAUGE_CMD_CURRENT               0x0A /* Current */
+#define SBS_GAUGE_CMD_AVG_CURRENT           0x0B /* AverageCurrent */
+#define SBS_GAUGE_CMD_MAX_ERROR             0x0C /* MaxError */
+#define SBS_GAUGE_CMD_RSOC                  0x0D /* RelativeStateOfCharge */
+#define SBS_GAUGE_CMD_ASOC                  0x0E /* AbsoluteStateOfCharge */
+#define SBS_GAUGE_CMD_REM_CAPACITY          0x0F /* RemainingCapacity */
+#define SBS_GAUGE_CMD_FULL_CAPACITY         0x10 /* FullChargeCapacity */
+#define SBS_GAUGE_CMD_RUNTIME2EMPTY         0x11 /* RunTimeToEmpty */
+#define SBS_GAUGE_CMD_AVG_TIME2EMPTY        0x12 /* AverageTimeToEmpty */
+#define SBS_GAUGE_CMD_AVG_TIME2FULL         0x13 /* AverageTimeToFull */
+#define SBS_GAUGE_CMD_CHG_CURRENT           0x14 /* ChargeCurrent */
+#define SBS_GAUGE_CMD_CHG_VOLTAGE           0x15 /* ChargeVoltage */
+#define SBS_GAUGE_CMD_FLAGS                 0x16 /* BatteryStatus */
+#define SBS_GAUGE_CMD_CYCLE_COUNT           0x17 /* CycleCount */
+#define SBS_GAUGE_CMD_NOM_CAPACITY          0x18 /* DesignCapacity */
+#define SBS_GAUGE_CMD_DESIGN_VOLTAGE        0x19 /* DesignVoltage */
+#define SBS_GAUGE_CMD_SPECS_INFO            0x1A /* SpecificationInfo */
+#define SBS_GAUGE_CMD_MANUFACTURER_DATE     0x1B /* ManufacturerDate */
+#define SBS_GAUGE_CMD_SN                    0x1C /* SerialNumber */
+#define SBS_GAUGE_CMD_MANUFACTURER_NAME     0x20 /* ManufacturerName */
+#define SBS_GAUGE_CMD_DEVICE_NAME           0x21 /* DeviceName */
+#define SBS_GAUGE_CMD_DEVICE_CHEM           0x22 /* DeviceChemistry */
+#define SBS_GAUGE_CMD_MANUFACTURER_DATA     0x23 /* ManufacturerData */
+
+#define SBS_GAUGE_DELAY                     1000
+
+struct sbs_gauge_config {
+	struct i2c_dt_spec i2c;
+};
+
+#endif

dts/bindings/fuel-gauge/sbs,sbs-gauge-new-api.yaml

@@ -0,0 +1,5 @@
+description: SBS 1.1 compliant fuel gauge (http://www.sbs-forum.org/specs)
+
+compatible: "sbs,sbs-gauge-new-api"
+
+include: [i2c-device.yaml, fuel-gauge.yaml]

subsys/emul/i2c/emul_sbs_gauge.c

@@ -6,9 +6,12 @@
  * Emulator for SBS 1.1 compliant smart battery fuel gauge.
  */
 
+#ifdef CONFIG_FUEL_GAUGE
+#define DT_DRV_COMPAT sbs_sbs_gauge_new_api
+#else
 #define DT_DRV_COMPAT sbs_sbs_gauge
+#endif /* CONFIG_FUEL_GAUGE */
 
-#define LOG_LEVEL CONFIG_SENSOR_LOG_LEVEL
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(sbs_sbs_gauge);
 

tests/drivers/fuel_gauge/sbs_gauge/CMakeLists.txt

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(device)
+
+FILE(GLOB app_sources src/test_sbs_gauge.c)
+target_sources(app PRIVATE ${app_sources})

tests/drivers/fuel_gauge/sbs_gauge/boards/native_posix.conf

@@ -0,0 +1,7 @@
+# Copyright (c) 2022 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_EMUL=y
+CONFIG_EMUL_SBS_GAUGE=y
+CONFIG_I2C=y
+CONFIG_I2C_EMUL=y

tests/drivers/fuel_gauge/sbs_gauge/boards/native_posix.overlay

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2022 Leica Geosystems AG
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	clock-frequency = <I2C_BITRATE_STANDARD>;
+	smartbattery: sbs_gauge@b {
+		compatible = "sbs,sbs-gauge-new-api";
+		reg = <0x0B>;
+		status = "okay";
+	};
+};

tests/drivers/fuel_gauge/sbs_gauge/boards/qemu_cortex_a9.conf

@@ -0,0 +1,7 @@
+# Copyright (c) 2022 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_EMUL=y
+CONFIG_EMUL_SBS_GAUGE=y
+CONFIG_I2C=y
+CONFIG_I2C_EMUL=y

tests/drivers/fuel_gauge/sbs_gauge/boards/qemu_cortex_a9.overlay

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2022 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/i2c/i2c.h>
+
+/ {
+	/* qemu_cortex_a9 board isn't configured with an I2C node */
+	fake_i2c_bus: i2c@100 {
+		status = "okay";
+		compatible = "zephyr,i2c-emul-controller";
+		clock-frequency = <I2C_BITRATE_STANDARD>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		reg = <0x100 4>;
+	};
+};
+
+&fake_i2c_bus {
+	clock-frequency = <I2C_BITRATE_STANDARD>;
+	compatible = "zephyr,i2c-emul-controller";
+	smartbattery0: smartbattery@b {
+		compatible = "sbs,sbs-gauge-new-api";
+		reg = <0x0B>;
+		status = "okay";
+	};
+};

tests/drivers/fuel_gauge/sbs_gauge/prj.conf

@@ -0,0 +1,7 @@
+CONFIG_ZTEST=y
+CONFIG_ZTEST_NEW_API=y
+CONFIG_I2C=y
+CONFIG_TEST_USERSPACE=y
+CONFIG_LOG=y
+
+CONFIG_FUEL_GAUGE=y

tests/drivers/fuel_gauge/sbs_gauge/src/test_sbs_gauge.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/fuel_gauge.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/ztest.h>
+#include <zephyr/ztest_assert.h>
+
+struct sbs_gauge_new_api_fixture {
+	const struct device *dev;
+	const struct battery_driver_api *api;
+};
+
+static void *sbs_gauge_new_api_setup(void)
+{
+
+	static struct sbs_gauge_new_api_fixture fixture;
+	const struct device *dev = DEVICE_DT_GET_ANY(sbs_sbs_gauge_new_api);
+	const struct battery_driver_api *api = dev->api;
+
+	fixture.dev = dev;
+	fixture.api = api;
+
+	zassert_true(device_is_ready(fixture.dev), "Fuel Gauge not found");
+	zassert_not_null(api);
+
+	return &fixture;
+}
+
+ZTEST_F(sbs_gauge_new_api, test_implemented_apis)
+{
+	zassert_not_equal(NULL, fixture->api->get_property);
+}
+
+ZTEST_F(sbs_gauge_new_api, test_voltage_read)
+{
+	struct fuel_gauge_get_property prop = {
+		.property_type = FUEL_GAUGE_VOLTAGE,
+	};
+	zassert_ok(fixture->api->get_property(fixture->dev, &prop, 1));
+}
+
+ZTEST_SUITE(sbs_gauge_new_api, NULL, sbs_gauge_new_api_setup, NULL, NULL, NULL);