driver: fuel_gauge/sy24561: add emulator

Add emulator for fuel gauge SY24561

Signed-off-by: Franck Duriez <[email protected]>

Author: franckduriez

drivers/fuel_gauge/sy24561/CMakeLists.txt

@@ -1 +1,4 @@
 zephyr_library_sources(sy24561.c)
+
+zephyr_include_directories_ifdef(CONFIG_EMUL_SY24561 .)
+zephyr_library_sources_ifdef(CONFIG_EMUL_SY24561 emul_sy24561.c)

drivers/fuel_gauge/sy24561/Kconfig

@@ -10,3 +10,12 @@ config SY24561
 	select I2C
 	help
 	  Enable driver for the silergy sy24561 fuel gauge device.
+
+config EMUL_SY24561
+	bool "Emulate a SY24561 fuel gauge"
+	default y
+	depends on EMUL
+	depends on SY24561
+	help
+	  It provides readings which follow a simple sequence, thus allowing
+	  test code to check that things are working as expected.

drivers/fuel_gauge/sy24561/emul_sy24561.c

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2025 Romain Paupe <[email protected]>, Franck Duriez <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Emulator for sy24561 fuel gauge
+ */
+
+#include <stdint.h>
+
+#include <zephyr/logging/log.h>
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/emul.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/i2c_emul.h>
+#include <zephyr/sys/byteorder.h>
+
+#include "sy24561.h"
+
+#define DT_DRV_COMPAT silergy_sy24561
+
+LOG_MODULE_REGISTER(EMUL_SY24561, CONFIG_FUEL_GAUGE_LOG_LEVEL);
+
+static uint8_t const version = 0x42;
+static uint8_t const soc = 75;
+static uint16_t const vbat_mV = 3200;
+static uint8_t const charging = 1;
+
+/** Static configuration for the emulator */
+struct sy24561_emul_cfg {
+	/** I2C address of emulator */
+	uint16_t addr;
+};
+
+static int emul_sy24561_reg_write(const struct emul *target, uint8_t reg, uint16_t val)
+{
+	return 0;
+}
+
+static int emul_sy24561_reg_read(const struct emul *target, uint8_t reg, uint16_t *val)
+{
+	switch (reg) {
+	case SY24561_REG_VERSION:
+		*val = version;
+		break;
+	case SY24561_REG_SOC:
+		*val = soc * 0xffff / 100;
+		break;
+	case SY24561_REG_STATUS:
+		*val = charging << 8;
+		break;
+	case SY24561_REG_VBAT:
+		*val = (vbat_mV - 2500) * 0x1000 / 2500;
+		break;
+	case SY24561_REG_CONFIG:
+		*val = 0x3C1C;
+		break;
+	case SY24561_REG_RESET:
+		*val = 0x0333;
+		break;
+	case SY24561_REG_POR:
+		*val = 0xffff;
+		break;
+	case SY24561_REG_MODE:
+		LOG_ERR("Attempt to read write only register 0x%x", reg);
+		return -EINVAL;
+	default:
+		LOG_ERR("Unknown register 0x%x read", reg);
+		return -EIO;
+	}
+	LOG_INF("read 0x%x = 0x%x", reg, *val);
+
+	return 0;
+}
+
+static int sy24561_emul_transfer_i2c(const struct emul *target, struct i2c_msg *msgs, int num_msgs,
+				     int addr)
+{
+	int ret;
+
+	__ASSERT_NO_MSG(msgs && num_msgs);
+
+	i2c_dump_msgs_rw(target->dev, msgs, num_msgs, addr, false);
+	switch (num_msgs) {
+	case 1:
+		if (msgs->flags & I2C_MSG_READ) {
+			LOG_ERR("Unexpected read");
+			return -EIO;
+		}
+
+		if (msgs->len != 3) {
+			LOG_ERR("Unexpected msg0 length %d", msgs->len);
+			return -EIO;
+		}
+
+		ret = emul_sy24561_reg_write(target, *msgs->buf, sys_get_be16(msgs->buf + 1));
+		if (ret) {
+			LOG_ERR("emul_sy24561_reg_write returned %d", ret);
+		}
+		break;
+	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;
+		}
+
+		if (msgs[1].flags & I2C_MSG_WRITE) {
+			LOG_ERR("Unexpected write");
+			return -EIO;
+		}
+		if (msgs[1].len != 2) {
+			LOG_ERR("Unexpected msg1 length %d", msgs[1].len);
+			return -EIO;
+		}
+
+		uint16_t val;
+
+		ret = emul_sy24561_reg_read(target, *msgs->buf, &val);
+		if (ret) {
+			LOG_ERR("emul_sy24561_reg_read returned %d", ret);
+			return ret;
+		}
+
+		sys_put_be16(val, msgs->buf);
+		break;
+	default:
+		LOG_ERR("Invalid number of messages: %d", num_msgs);
+		return -EIO;
+	}
+
+	return ret;
+}
+
+static const struct i2c_emul_api sy24561_emul_api_i2c = {
+	.transfer = sy24561_emul_transfer_i2c,
+};
+
+static int emul_sy24561_init(const struct emul *target, const struct device *parent)
+{
+	ARG_UNUSED(target);
+	ARG_UNUSED(parent);
+
+	return 0;
+}
+
+#define SY24561_EMUL(n)                                                                            \
+	static const struct sy24561_emul_cfg sy24561_emul_cfg_##n = {                              \
+		.addr = DT_INST_REG_ADDR(n),                                                       \
+	};                                                                                         \
+	EMUL_DT_INST_DEFINE(n, emul_sy24561_init, NULL, &sy24561_emul_cfg_##n,                     \
+			    &sy24561_emul_api_i2c, NULL)
+
+DT_INST_FOREACH_STATUS_OKAY(SY24561_EMUL)