zephyr: Fix I2C_PASSTHRU host command

ZephyrEC uses different I2C port numbers than CrosEC does, so convert
the received remote port via I2C_PASSTHRU command into a proper one.
The conversion is done based on a new property remote-port, which tells
what port number is used by external components like kernel.

The change fixes an issue with unexpected entering OTG mode by the
charger.

BUG=b:188885798
BRANCH=none
TEST=Flash Lazor and make sure that no "charge problem" prints are
displayed.

Signed-off-by: Dawid Niedzwiecki <dn@semihalf.com>
Change-Id: Id00265a3abf286ca59cbecb38ff7933d75e0d361
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2933296
Reviewed-by: Yuval Peress <peress@chromium.org>

4 files changed, 35 insertions, 0 deletions

diff --git a/zephyr/dts/bindings/i2c/cros-ec-i2c-port-base.yaml b/zephyr/dts/bindings/i2c/cros-ec-i2c-port-base.yaml
index d00e1346b8..7f7350b668 100644
--- a/zephyr/dts/bindings/i2c/cros-ec-i2c-port-base.yaml
+++ b/zephyr/dts/bindings/i2c/cros-ec-i2c-port-base.yaml
@@ -7,6 +7,12 @@ properties:
   i2c-port:
     type: phandle
     required: true
+  remote-port:
+    type: int
+    required: false
+    description:
+      A port number used by remote components like Kernel via the I2C_PASSTHRU
+      Host Command
   enum-name:
     type: string
     required: true
diff --git a/zephyr/projects/trogdor/boards/arm/trogdor/trogdor.dts b/zephyr/projects/trogdor/boards/arm/trogdor/trogdor.dts
index 7e3100a0fe..e2d57af8fc 100644
--- a/zephyr/projects/trogdor/boards/arm/trogdor/trogdor.dts
+++ b/zephyr/projects/trogdor/boards/arm/trogdor/trogdor.dts
@@ -40,6 +40,7 @@
 		};
 		battery {
 			i2c-port = <&i2c0_0>;
+			remote-port = <0>;
 			enum-name = "I2C_PORT_BATTERY";
 			label = "BATTERY";
 		};
diff --git a/zephyr/shim/include/i2c/i2c.h b/zephyr/shim/include/i2c/i2c.h
index 930a6447a1..f227da48b1 100644
--- a/zephyr/shim/include/i2c/i2c.h
+++ b/zephyr/shim/include/i2c/i2c.h
@@ -39,4 +39,16 @@ enum i2c_ports {
  */
 const struct device *i2c_get_device_for_port(const int port);
 
+/**
+ * @brief Get a port number for a received remote port number.
+ *
+ * This function translate a received port number via the I2C_PASSTHRU host
+ * command to a port number used in ZephyrEC based on remote_port property in
+ * dts. The first port which matches the remote port number is returned.
+ *
+ * @param port The received remote port.
+ * @return Port number used in EC. -1 if the remote port is not defined
+ */
+int i2c_get_port_from_remote_port(int remote_port);
+
 #endif /* ZEPHYR_CHROME_I2C_I2C_H */
diff --git a/zephyr/shim/src/i2c.c b/zephyr/shim/src/i2c.c
index b3b2117b98..7c6ffa765b 100644
--- a/zephyr/shim/src/i2c.c
+++ b/zephyr/shim/src/i2c.c
@@ -16,6 +16,9 @@
 	i2c_devices[I2C_PORT(id)] = device_get_binding( \
 		DT_PROP_BY_PHANDLE(id, i2c_port, label));
 
+#define INIT_REMOTE_PORTS(id) \
+	i2c_remote_ports[I2C_PORT(id)] = DT_PROP_OR(id, remote_port, -1);
+
 #define I2C_CONFIG_GPIO(id, type) \
 	DT_ENUM_UPPER_TOKEN(DT_CHILD(DT_CHILD(id, config), type), enum_name)
 
@@ -38,6 +41,7 @@ const struct i2c_port_t i2c_ports[] = {
 #endif
 };
 const unsigned int i2c_ports_used = ARRAY_SIZE(i2c_ports);
+static int i2c_remote_ports[I2C_PORT_COUNT];
 
 int i2c_get_line_levels(int port)
 {
@@ -50,6 +54,7 @@ static int init_device_bindings(const struct device *device)
 {
 	ARG_UNUSED(device);
 	DT_FOREACH_CHILD(DT_PATH(named_i2c_ports), INIT_DEV_BINDING)
+	DT_FOREACH_CHILD(DT_PATH(named_i2c_ports), INIT_REMOTE_PORTS)
 	return 0;
 }
 SYS_INIT(init_device_bindings, POST_KERNEL, 51);
@@ -60,3 +65,14 @@ const struct device *i2c_get_device_for_port(const int port)
 		return NULL;
 	return i2c_devices[port];
 }
+
+int i2c_get_port_from_remote_port(int remote_port)
+{
+	for (int port = 0; port < I2C_PORT_COUNT; port++) {
+		if (i2c_remote_ports[port] == remote_port)
+			return port;
+	}
+
+	/* Remote port is not defined, return -1 to signal the problem */
+	return -1;
+}