zephyr: Add pi3usb9201 emulator and test

BUG=b:184852906
BRANCH=none
TEST=zmake configure --test zephyr/test/drivers

Change-Id: Ie554b6957269c638357d82d6f5dcc2ceda08caab
Signed-off-by: Edward Hill <ecgh@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2961272
Commit-Queue: Keith Short <keithshort@chromium.org>
Reviewed-by: Keith Short <keithshort@chromium.org>

3 files changed, 209 insertions, 0 deletions

diff --git a/zephyr/emul/CMakeLists.txt b/zephyr/emul/CMakeLists.txt
index 0a97a35df6..f490dc2b03 100644
--- a/zephyr/emul/CMakeLists.txt
+++ b/zephyr/emul/CMakeLists.txt
@@ -4,3 +4,4 @@
 
 zephyr_library_sources_ifdef(CONFIG_EMUL_SMART_BATTERY	emul_smart_battery.c)
 zephyr_library_sources_ifdef(CONFIG_EMUL_BMA255		emul_bma255.c)
+zephyr_library_sources_ifdef(CONFIG_EMUL_BC12_DETECT_PI3USB9201	emul_pi3usb9201.c)
diff --git a/zephyr/emul/Kconfig b/zephyr/emul/Kconfig
index bbf492ea8d..c2850e3e2b 100644
--- a/zephyr/emul/Kconfig
+++ b/zephyr/emul/Kconfig
@@ -13,3 +13,10 @@ config EMUL_BMA255
 	  Enable the BMA255 emulator. This driver use emulated I2C bus.
 	  It is used to test bma2x2 driver. Emulators API is available in
 	  zephyr/include/emul/emul_bma255.h
+
+config EMUL_BC12_DETECT_PI3USB9201
+	bool "PI3USB9201 emulator"
+	help
+	  Enable the PI3USB9201 emulator. PI3USB9201 is a BC1.2 charger
+	  detector/advertiser. The emulator supports reading and writing the
+	  4 I2C registers of the PI3USB9201 using the emulated I2C bus.
diff --git a/zephyr/emul/emul_pi3usb9201.c b/zephyr/emul/emul_pi3usb9201.c
new file mode 100644
index 0000000000..d00ffe24c6
--- /dev/null
+++ b/zephyr/emul/emul_pi3usb9201.c
@@ -0,0 +1,201 @@
+/* Copyright 2021 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#define DT_DRV_COMPAT zephyr_pi3usb9201_emul
+
+#include <device.h>
+#include <emul.h>
+#include <drivers/i2c.h>
+#include <drivers/i2c_emul.h>
+
+#include "emul/emul_pi3usb9201.h"
+
+#include <logging/log.h>
+LOG_MODULE_REGISTER(emul_pi3usb9201, LOG_LEVEL_DBG);
+
+#define EMUL_REG_COUNT (PI3USB9201_REG_HOST_STS + 1)
+#define EMUL_REG_IS_VALID(reg) (reg >= 0 && reg < EMUL_REG_COUNT)
+
+/** Run-time data used by the emulator */
+struct pi3usb9201_emul_data {
+	/** I2C emulator detail */
+	struct i2c_emul emul;
+	/** pi3usb9201 device being emulated */
+	const struct device *i2c;
+	/** Configuration information */
+	const struct pi3usb9201_emul_cfg *cfg;
+	/** Current state of all emulated pi3usb9201 registers */
+	uint8_t reg[EMUL_REG_COUNT];
+};
+
+/** Static configuration for the emulator */
+struct pi3usb9201_emul_cfg {
+	/** Label of the I2C bus this emulator connects to */
+	const char *i2c_label;
+	/** Pointer to run-time data */
+	struct pi3usb9201_emul_data *data;
+	/** Address of pi3usb9201 on i2c bus */
+	uint16_t addr;
+};
+
+int pi3usb9201_emul_set_reg(struct i2c_emul *emul, int reg, uint8_t val)
+{
+	struct pi3usb9201_emul_data *data;
+
+	if (!EMUL_REG_IS_VALID(reg))
+		return -EIO;
+
+	data = CONTAINER_OF(emul, struct pi3usb9201_emul_data, emul);
+	data->reg[reg] = val;
+
+	return 0;
+}
+
+int pi3usb9201_emul_get_reg(struct i2c_emul *emul, int reg, uint8_t *val)
+{
+	struct pi3usb9201_emul_data *data;
+
+	if (!EMUL_REG_IS_VALID(reg))
+		return -EIO;
+
+	data = CONTAINER_OF(emul, struct pi3usb9201_emul_data, emul);
+	*val = data->reg[reg];
+
+	return 0;
+}
+
+static void pi3usb9201_emul_reset(struct i2c_emul *emul)
+{
+	struct pi3usb9201_emul_data *data;
+
+	data = CONTAINER_OF(emul, struct pi3usb9201_emul_data, emul);
+
+	data->reg[PI3USB9201_REG_CTRL_1]     = 0;
+	data->reg[PI3USB9201_REG_CTRL_2]     = 0;
+	data->reg[PI3USB9201_REG_CLIENT_STS] = 0;
+	data->reg[PI3USB9201_REG_HOST_STS]   = 0;
+}
+
+/**
+ * Emulate an I2C transfer to a pi3usb9201
+ *
+ * This handles simple reads and writes
+ *
+ * @param emul I2C emulation information
+ * @param msgs List of messages to process
+ * @param num_msgs Number of messages to process
+ * @param addr Address of the I2C target device
+ *
+ * @retval 0 If successful
+ * @retval -EIO General input / output error
+ */
+static int pi3usb9201_emul_transfer(struct i2c_emul *emul, struct i2c_msg *msgs,
+				    int num_msgs, int addr)
+{
+	const struct pi3usb9201_emul_cfg *cfg;
+	struct pi3usb9201_emul_data *data;
+	unsigned int len;
+	int ret, i, reg;
+	bool read;
+
+	data = CONTAINER_OF(emul, struct pi3usb9201_emul_data, emul);
+	cfg = data->cfg;
+
+	if (cfg->addr != addr) {
+		LOG_ERR("Address mismatch, expected %02x, got %02x", cfg->addr,
+			addr);
+		return -EIO;
+	}
+
+	i2c_dump_msgs("emul", msgs, num_msgs, addr);
+
+	if (num_msgs == 1) {
+		if (!(((msgs[0].flags & I2C_MSG_RW_MASK) == I2C_MSG_WRITE)
+		      && (msgs[0].len == 2))) {
+			LOG_ERR("Unexpected write msgs");
+			return -EIO;
+		}
+		return pi3usb9201_emul_set_reg(emul, msgs[0].buf[0],
+					       msgs[0].buf[1]);
+	} else if (num_msgs == 2) {
+		if (!(((msgs[0].flags & I2C_MSG_RW_MASK) == I2C_MSG_WRITE)
+		      && (msgs[0].len == 1)
+		      && ((msgs[1].flags & I2C_MSG_RW_MASK) == I2C_MSG_READ)
+		      && (msgs[1].len == 1))) {
+			LOG_ERR("Unexpected read msgs");
+			return -EIO;
+		}
+		return pi3usb9201_emul_get_reg(emul, msgs[0].buf[0],
+					       &(msgs[1].buf[0]));
+	} else {
+		LOG_ERR("Unexpected num_msgs");
+		return -EIO;
+	}
+
+}
+
+/* Device instantiation */
+
+static struct i2c_emul_api pi3usb9201_emul_api = {
+	.transfer = pi3usb9201_emul_transfer,
+};
+
+/**
+ * @brief Set up a new pi3usb9201 emulator
+ *
+ * This should be called for each pi3usb9201 device that needs to be
+ * emulated. It registers it with the I2C emulation controller.
+ *
+ * @param emul Emulation information
+ * @param parent Device to emulate
+ *
+ * @return 0 indicating success (always)
+ */
+static int pi3usb9201_emul_init(const struct emul *emul,
+			 const struct device *parent)
+{
+	const struct pi3usb9201_emul_cfg *cfg = emul->cfg;
+	struct pi3usb9201_emul_data *data = cfg->data;
+	int ret;
+
+	data->emul.api = &pi3usb9201_emul_api;
+	data->emul.addr = cfg->addr;
+	data->i2c = parent;
+	data->cfg = cfg;
+
+	ret = i2c_emul_register(parent, emul->dev_label, &data->emul);
+
+	pi3usb9201_emul_reset(&data->emul);
+
+	return ret;
+}
+
+#define PI3USB9201_EMUL(n)					\
+	static struct pi3usb9201_emul_data			\
+		pi3usb9201_emul_data_##n = {};			\
+								\
+	static const struct pi3usb9201_emul_cfg			\
+		pi3usb9201_emul_cfg_##n = {			\
+		.i2c_label = DT_INST_BUS_LABEL(n),		\
+		.data = &pi3usb9201_emul_data_##n,		\
+		.addr = DT_INST_REG_ADDR(n),			\
+	};							\
+	EMUL_DEFINE(pi3usb9201_emul_init, DT_DRV_INST(n),	\
+		    &pi3usb9201_emul_cfg_##n)
+
+DT_INST_FOREACH_STATUS_OKAY(PI3USB9201_EMUL)
+
+#define PI3USB9201_EMUL_CASE(n)					\
+	case DT_INST_DEP_ORD(n): return &pi3usb9201_emul_data_##n.emul;
+
+struct i2c_emul *pi3usb9201_emul_get(int ord)
+{
+	switch (ord) {
+	DT_INST_FOREACH_STATUS_OKAY(PI3USB9201_EMUL_CASE)
+
+	default:
+		return NULL;
+	}
+}